But the authors also suspect that their forelimbs were especially muscular.
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Like a bird, it had small, light bones and wing-like forelimbs.
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Karl Gegenbaur's sketch of corresponding parts of the human hand to forelimbs (1870).
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That included developing extremely elongated necks and forelimbs, smaller skulls and thick, trunk-like limbs.
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Due to the lack of forelimbs, the researchers believe they disappeared much earlier before hindlimbs.
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Over time, a number of other theropod dinosaurs have been found that also have reduced forelimbs.
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These bent forelimbs were "unlike any of their marsupial kin, living or extinct," the study authors wrote.
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The forelimbs of this dinosaur are more "crouched," while being very thick to support its giant body.
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According to fossil records, snakes had a complete set of forelimbs and hindlimbs about 150 million years ago.
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From the DNA, the scientists found that the Scythians bred for certain characteristics: stockier forelimbs that were thicker.
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But further study showed that it was in fact a tiny therapod dinosaur with unique forelimbs and membranous wings.
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Dr. Wang assumed Ambopteryx was a bird because the animal sported relatively long forelimbs, just as modern birds do.
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Bogart the camel was born with hyper-mobile joints in his forelimbs, which prevent him from standing straight and walking.
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Emtech, a 3-year-old colt, had two broken front forelimbs, track owners the Stronach Group said in a news release.
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Gualicho had feeble forelimbs and only two fingers, just like T. rex, which lived in North America almost 25 million years later.
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The 1-ton meat-eater was armed with sharp teeth and had forelimbs with four fingers, three of which formed powerful claws.
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Thyalacoleo carnifex, a type of marsupial lion, weight more than 220 pounds, had a stiff tail for balancing and powerful forelimbs for climbing.
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The new study suggests that those mysterious proto-snakes probably lost their forelimbs early in snake evolution, at least 170 million years ago.
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Its forelimbs were shaped less like wings and more like flippers, similar to those used by marine reptiles like the plesiosaur to swim.
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Typically, these pectoral and pelvic fins — which correspond to forelimbs and hindlimbs in land vertebrates — are small and largely used for balance and steering.
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"They have a lightly constructed, narrow skull with horns or crests on their skull roof, and relatively robust forelimbs with three fingers," Hattori said.
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The dilophosaurus may have survived the encounter, but the injuries "must have severely compromised the use of the forelimbs in prey capture," wrote the researchers.
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Scientists believe that during their evolution, theropods lifted their forelimbs off the ground and modified them for catching prey, and bird wings evolved from there.
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Inside the iridescent crystal, Berger found the silhouette of an insect frozen in a dramatic pose, with its forelimbs outstretched and its jaws wide open.
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Credit: Colin Donihue Those long forelimbs and toe pads would have allowed these anoles to cling to surfaces during gale-force winds brought by the hurricanes.
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The slab, which dated to the middle Triassic Period, contained the front half of a small, slightly squashed skeleton with a large head and heavy forelimbs.
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They tend to be on the smaller size, about the size of large dogs, and with sprawling forelimbs that come out from the side, similar to lizards.
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They also found a third pile, which contained a lower back vertebra, part of the pelvis, some more bones from the forelimbs and a lot of ribs.
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The research team found that the surviving population had larger toe pads, longer forelimbs and shorter hind limbs on average than the lizards surveyed before the storms.
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The team also discovered evidence that hatchlings had leg bones that were more developed than their forelimbs, suggesting the babies most likely crawled and were unable to fly.
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To investigate, Jing-Shan Zhao of Tsinghua University in Beijing looked into an animal called Caudipteryx, a ground-dwelling animal with "feathered forelimbs that could be considered "proto-wings.
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The saber-toothed cat most likely suffered damage to its lower back while it twisted and turned trying to wrestle large prey to the ground with its massive forelimbs.
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Depending on a dog&aposs body shape, the design of these harnesses can potentially result in chafing under the armpits and stress on muscles and tendons in the forelimbs.
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And then it came to me: They reminded me of those C.G.I. velociraptors in films, except that the scales have turned to feathers and the stunted forelimbs to vibrant wings.
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One clump contained the skull, and about nine feet away there was a pile that had a shoulder blade, some vertebrae, a rib and parts of the forelimbs and hindlimbs.
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The utility of puny arms, the scientific term for which is reduced forelimbs, has been a long-standing mystery in paleontology since they were first discovered on the T. rex.
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Paleontologists studying an unusual fossil have identified a new dinosaur, related to the velociraptor, that had a neck like a swan, a snout like a goose and forelimbs like flippers.
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"The powerful forelimbs equipped with grasping hands and slashing first digit would amply serve to both to restrain a victim or a carcass," Wells and Camens said in the study.
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Found in the sandy deserts of Western Australia, South Australia and the Northern Territory, people often spot the marsupial mole's tracks due to their spade-like forelimbs, used primarily for digging.
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With Microraptor, paleontologists beheld the first dinosaur outfitted with asymmetrical feathers on its hind limbs and forelimbs — that is, feathers designed specifically to aid flight instead of for warmth or display.
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What they found: As the winds increased, the scientists found that the lizards tucked their forelimbs close to their body, but jutted out their hind limbs at a 90-degree angle.
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"[T]he dragons are anatomically correct, with forelimbs becoming the wings (as in bats), rather than having separate wings sprouting from their backs, which has no precedent in Earth's biodiversity," he said.
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Longer than an ocean liner and powered by strong forelimbs for grabbing unsuspecting creatures, the monster also had a graceful, feline-esque shape with shoulder blades above its spine and a long tail.
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With the evolution of bipedality (two-legged stance) in the first human ancestors ~6 million years ago, these primates stopped using their forelimbs for locomotion and had to rely exclusively on the hindlimbs to walk upright.
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This turkey-sized Mongolian dinosaur from about 75 million years ago had an elongated neck, reduced forelimbs that may have helped it swim, a slim and short snout, and a mouth full of small sharp teeth.
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Although Gualicho shinyae comes from a different line of dinosaurs, studying its wimpy arms may provide some insight into the evolutionary pressures that might cause a giant like T-rex to end up with tiny forelimbs.
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"Combining these features suggests Dineobellator would have been a swift, skilled pursuit predator that could run down smaller prey and attack and jump onto larger prey, holding on with stronger forelimbs and a tighter grip," Jasinski said.
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What they're saying: Dionne Benson, chief veterinarian for Santa Anita owner The Stronach Group, said in a statement the racecourse would "open an immediate review into what factors could have contributed to Emtech's injury," described as 2 broken forelimbs.
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As the researchers summarize: These analyses suggest that the impetus of the evolution of powered flight in the theropod lineage that lead to Aves may have been an entirely natural phenomenon produced by bipedal motion in the presence of feathered forelimbs.
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Paleontologist Peter Makovicky, curator of dinosaurs at the Field Museum in Chicago, said Gualicho's short, two-fingered forelimbs strongly resembled those of some members of a theropod group called tyrannosaurs including T. rex, even though Gualicho was only distantly related to them.
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The bottom line: The study, along with other research, puts forward the idea that membranous wings and elongated forelimbs in scansoriopterygids were likely short-lived evolutionary experiments with flight, since feathered wings and the birds we know of today came to predominate later.
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According to this theory, the fangs were only put to use once a saber-toothed cat brought its prey down to the ground with its huge forelimbs, at which point the elongated upper canines were used to pierce through the soft, vulnerable neck.
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Now, researchers from Japan have identified what they believe to be another feature that sets the reptiles apart: Alligators tend to have shorter humerus bones in their forelimbs and shorter femurs in their hind limbs than crocodiles, the team reported last week.
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Muttluks Deluxe, set of 4 boots, $80 to $85 — available fall 2020For outdoor adventures in deep snow, Muttluks has extended the length of its cuff and added a side-zipper opening and top cinching Velcro strap to keep forelimbs dry and warm.
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"Its short, strong forelimbs and large claws would have permitted T-Rex, whether mounted on a victim's back or grasping it with its jaws, to inflict four gashes a metre or more long and several centimetres deep within a few seconds," said Stanley, according to New Scientist.
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They can move the toes on their forelimbs to grasp things. Their hindlimbs tend to be longer than their forelimbs, like rabbits.
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Like Archaeopteryx it had long forelimbs. Its femur was longer than its humerus, 84 mm as against 71 mm, which might indicate that it stood on its hind limbs and could use its forelimbs for flapping. Xiaotingia had feathers on its head, body, forelimbs and hind limbs. The feathers on the femur were quite long, measuring 55 mm.
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Head and forelimbs of V. mobydick. Mermaid skinks have only forelimbs, no hind limbs, hence the common name "mermaid skink". This species's forelimbs are shaped like flippers (Voeltzkowia yamagishii has claws). The scientific name Voeltzkowia mobydick consists of the pre-existing parent genus Voeltzkowia, and the name of the white sperm whale from the 1851 novel Moby-Dick by Herman Melville.
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Some quadrupeds are able to walk bipedally on their forelimbs, thus performing "hand" walking in an anthropomorphic sense. For example, when attacked, the spotted skunk may rear up and move about on its forelimbs so that its anal glands, capable of spraying an offensive oil, are directed towards the attacker. Dogs and sealions can also be trained to walk on their forelimbs.
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The left or underside of the skeleton was preserved in carbonaceous clay, making it difficult to expose the skin. The skeleton was articulated, and only missing about the last of the tail and the forelimbs. Both scapulae and coracoids are preserved in position, but the rest of the forelimbs are gone, except for phalanges and pieces of humeri, ulnae and radii. Apparently the remaining forelimbs were weathered or eroded away.
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For example, putative forelimbs discovered in Adelogyrinus and Palaeomolgophis by Brough & Brough (1967) were re-identified as hyoid bones and ribs, respectively. Carroll (1967) also claimed that forelimbs were present in Adelospondylus, but these later considered to be hyoids as in Adelogyrinus.
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The upper surfaces of forelimbs and posterior hind limbs are purple to brown, while the chest and ventral sides of forelimbs pinkish and the venter and ventral sides of hind limbs are pinkish brown. The iris is orange and has fine, black reticulum.
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This strongly suggested that T. rex had similar forelimbs, but this hypothesis was not confirmed until the first complete T. rex forelimbs were identified in 1989, belonging to MOR 555 (the "Wankel rex"). The remains of Sue also include complete forelimbs. T. rex arms are very small relative to overall body size, measuring only long, and some scholars have labelled them as vestigial. The bones show large areas for muscle attachment, indicating considerable strength.
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This was recognized as early as 1906 by Osborn, who speculated that the forelimbs may have been used to grasp a mate during copulation. It has also been suggested that the forelimbs were used to assist the animal in rising from a prone position. Diagram illustrating arm anatomy Another possibility is that the forelimbs held struggling prey while it was killed by the tyrannosaur's enormous jaws. This hypothesis may be supported by biomechanical analysis.
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The skunk has long claws and well developed forelimbs in order to dig to locate prey.
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Resting on or using the forelimbs for locomotion may have been possible (as indicated by tracks of a resting theropod), but if this was the norm, the forelimbs would probably have showed adaptations for this. Hone and Holtz furthermore suggested that the forelimbs of spinosaurids do not seem optimal for trapping prey, but instead appear similar to the forelimbs of digging animals. They suggested that the ability to dig would have been useful when excavating nests, digging for water, or to reach some kinds of prey. Hone and Holtz also believed that spinosaurids would have waded and dipped in water rather than submerging themselves, due to their sparsity of aquatic adaptations.
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Orthograde clamber is when the majority of the body mass is held up by the forelimbs. However, there are few instances when the hind limbs carry most of the body weight, only using forelimbs for support. This bipedal posture and motion are most often seen during feeding.
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With the forelimbs being approximately 64% of the hindlimbs, Postosuchus had small hands bearing five toes. Only the first toe bore a large claw, which was used as an offensive weapon, and the forelimbs were robust, probably to hold the prey.Peyer et al. (2008), p. 380.
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Historically, there has been debate over whether or not rauisuchids like Postosuchus were mainly bipedal or quadrupedal. Each one of Postosuchus's two forelimbs was slightly over half the size of the hindlimbs.Chatterjee (1985), p. 428. This characteristic of short forelimbs can usually be seen in bipedal reptiles.
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The forelimbs of istiodactylids were large, up to 4.5 times longer than their legs. The long wing-finger may have occupied 50 percent of the wing-skeleton. The hindlimbs were short compared to the forelimbs, and the feet were as long as the small third finger.
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It has been proposed that sauropods possessed a four-chambered double pump heart, with one pump for oxygenated and one pump for deoxygenated blood. As in all Macronaria, the forelimbs of brachiosaurids are long relative to the hindlimbs, but this trait is more pronounced in brachiosaurids. The forelimbs were very slender for a sauropod and the metacarpal bones of the forelimb were elongated. These adaptations overall increased the stride length of the forelimbs, arguably resulting in an uneven gait.
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These frogs have extensive webbing between their forelimbs and hindlimbs, allowing them to glide through the air.
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Model Megantereon was built like a large modern jaguar, but somewhat heavier. It had stocky forelimbs with the lower half of these forelimbs lion-sized. It had large neck muscles designed to deliver a powerful shearing bite. The elongated upper canines were protected by flanges at the mandible.
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The holotype specimen (USNM 13627) was collected in 1909 by Robert Anderson, and consists of pieces of both forelimbs. Known Pliopedia fossils include a humerus, pieces of radius and ulna from both forelimbs, metacarpals, metatarsals, and phalanges. They were discovered in the Paso Robles Formation of San Luis Obispo County, California.
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Like Diictodon, Eosimops likely used its forelimbs for postural support and digging and its hind limbs for impact loading.
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It is one of only two species (the other being Babina holsti) to possess a "pseudothumb" on the forelimbs.
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The male ritualistic display includes repeated partial erections of the frill, head bobbing, tail lashing, and waving of forelimbs.
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By contrast, when a male amphibian clasps behind the forelimbs (axillary region) of the female, this is considered axillary amplexus.
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This connection is more tenuous, however, since Desmatosuchus have a crest over their hind limbs but lack one on their forelimbs, meaning that they likely didn't have the musculature for digging with their forelimbs the way armadillos do. In spite of these parallels, the general consensus is still that Desmatosuchus was most likely herbivorous.
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Chalicotheriines are one of the two subfamilies of the extinct family Chalicotheriidae, a group of herbivorous, odd-toed ungulate (perissodactyl) mammals that lived from the Eocene to the Pleistocene. The other subfamily is the Schizotheriinae. Chalcotheriines evolved unique characteristics for ungulates, with very long forelimbs, short hindlimbs, and a relatively gorilla-like physique, including knuckle-walking on their flexible forelimbs, which bore long curved claws. Members of this subfamily possessed some of the longest forelimbs and shortest hindlimbs in relation to each other out of all extinct animals.
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Therefore, it may have been anatomically impossible for Microraptor to have used its clawed forelimbs in capturing prey or manipulating objects.
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The reduction of digits is one of the defining features of tyrannosaurids, only having two functional digits on very short forelimbs.
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The limbs of S. kasneri are greatly reduced. The forelimbs are entirely lost, and the hind limbs retain only two digits.
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The forelimbs are covered with large transverse scales. Both the forelimbs and the hind limbs are webbed, reflecting their largely aquatic habits. The necks of black marsh turtles are characteristically thick, forming a collar around the head when it is retracted into the shell. All of the limbs, the tail, and the neck are dark gray to black.
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Actual mating involves amplexus, whereby the male grasps the female with his forelimbs posterior to her forelimbs. The female releases her eggs and the male simultaneously releases sperm which swim to the egg mass. Fertilization takes place in the water. A single egg clutch may consist of 1000 to 7000 eggs, which may be attached to submerged vegetation.
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In Mantellisaurus the forelimbs were about half the length of the hindlimbs whereas they were about 70 percent the length of the hindlimbs in I. bernissartensis. Due to the short length of its forelimbs and the shortness of its body, Paul proposed that it was primarily bipedal, only going on all fours when standing still or moving slowly.
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Struthiomimus had longer hands relative to the humerus than other ornithomimids, with particularly long claws. Their forelimbs were more robust than Ornithomimus.
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The body is covered by tiny spinules. The forelimbs are elongate and slender. The hind limbs are slender. The toes are webbed.
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Dunn, 1935, p. 536; Miralles et al., 2009, p. 57 The hindlimbs are longer and stronger than the forelimbs, which are small.
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From one of the forelimbs it appears that Sphenosuchus has a carpus with the radius and ulna elongated and metacarpal like in structure.
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Most restorations of ceratopsians show them with erect hindlimbs but semi-sprawling forelimbs, which suggest that they were not fast movers. But Paul and Christiansen (2000) argued that at least the later ceratopsians had upright forelimbs and the larger species may have been as fast as rhinos, which can run at up to 56 km or 35 miles per hour.
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To make powered flight possible, bats had to evolve several features. Bat flight necessitated the increase of membrane surface area between the digits of the forelimbs, between the forelimbs and hindlimbs, and between the hindlimbs. Bats also had to evolve a thinner cortical bone to reduce torsional stresses produced by propulsive downstroke movements.Swartz, S. M., Bennett, M. B., & Carrier, D. R. (1992).
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The hind limbs of the dog and horse have a slightly greater mass than the forelimbs, whereas the elephant has proportionally longer limbs. The elephant's forelimbs are longer than its hind limbs. In the horse and dog, the hind limbs play an important role in primary propulsion. The legged locomotion of humans generally distributes an equal loading on each lower limb.
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While microbats only have claws on the thumbs of their forelimbs, most megabats have a clawed second digit as well; only Eonycteris, Dobsonia, Notopteris, and Neopteryx lack the second claw. The first digit is the shortest, while the third digit is the longest. The second digit is incapable of flexion. Megabats' thumbs are longer relative to their forelimbs than those of microbats.
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Klicks have strange, wedge-shaped bodies covered with smooth, chitinous plates. They possess six multi-jointed legs ending in thick claws, and an additional pair of forelimbs ending in sharp, manipulating claws. A Klick's sensory organs hang in a pendulous glob below the main part of its body, between the forelimbs. The Klicks employ brutal but effective "hit-and- run" combat tactics.
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Philochortus zolii digs burrows in the sandy soil below the clumps of grasses and uses its forelimbs to push sand out of its burrow.
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The upper incisors were much smaller. The forelimbs of Ronzotherium were tetradactyl with a prominent central metapodal. The hindlimbs however were tridactyl, with three toes.
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Vomerine ridge is absent. Forelimbs are shorter than hand length. Fingers are short and without adhesive discs. Subarticular tubercles are prominent and round in shape.
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Supra-tympanic fold is absent. Forelimbs are long and slender. The finger tips have expanded discs; no webbing is present. The hind limbs are robust.
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The toes are long and have distinct adhesive discs and webbing extending midway to the discs. The forelimbs are short but muscular with webbed fingers.
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The forelimbs have five claws, are long and slightly flattened. They are covered with fine, dark scales and slightly overlapping larger scales on front in the same color as the head. The hind limbs are elephant-like with four claws, and are covered in small scales colored like the forelimbs. The tail varies in length by gender and has a row of colored scales on the sides.
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The forelimbs were generally similar to those of other early reptiles. The humerus (upper arm bone) was slightly longer than the ulna and radius (lower arm bones). The knobs and joints forming the elbow were poorly developed, meaning that Erpetonyx may have had more flexible forelimbs than its contemporaries. The hand was incomplete, and some the carpals (wrist bones) were large while others were unusually small.
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The order Chiroptera, comprising all bats, has evolved the unique mammalian adaptation of flight. Bat wings are modified tetrapod forelimbs. Because bats are mammals, the skeletal structures in their wings are morphologically homologous to the skeletal components found in other tetrapod forelimbs. Through adaptive evolution these structures in bats have undergone many morphological changes, such as webbed digits, elongation of the forelimb, and reduction in bone thickness.
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Another major difference in bat forelimbs is in the density of their skeletal limbs. The bones found in their forelimbs are reduced to achieve a light body weight required for flight. In particular, their ulna is reduced in width and fused to the other zeugopod element, the radius. One of the possible molecular pathways involved in reduction of bat skeletal forelimb thickness is differences in SHH expression.
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The forelimbs of Appalachiosaurus are poorly known. Large tyrannosaurids are characterized by proportionally small forelimbs and hands with two functional digits each; except some reports of a humerus ascribed to Appalachiosaurus, no forelimb material are known. Early reconstructions gave it long arms with three fingers, but they are now thought to have been much shorter, with only two fingers. Museum mounts have been corrected accordingly.
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Although the palms of the mummy face backwards, this is because the carcass lay on its back, which caused the forelimbs to sprawl and the humeri to detach from the shoulder joints. In both forelimbs of the mummy, radius and ulna are parallel to each other and the radius is connected to the outer condyle, confirming that the palm must have faced inwards in life.
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Size of Poekilopleuron compared to a human The most distinctive feature of Poekilopleuron were its forelimbs. Their length, about 60 cm, was a sign of this theropod's more original build. Unlike later Theropoda, whose forelimbs tended toward reduction in length in proportion to the animals' size, Poekilopleuron's were long and, by implication, potent. The length mostly resided in the elongated but powerfully muscled humerus.
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Carpenter (2002) examined the bio-mechanics of theropods forelimbs and attempted to evaluate their usefulness in predation. He concluded that the forelimb of Coelophysis was flexible and had a good range of motion, but its bone structure suggested that it was comparatively weak. The "weak" forelimbs and small teeth in this genus, suggested that Coelophysis preyed upon animals that were substantially smaller than itself. Rinehart et al.
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A bat is a mammal and its forearm bones have been adapted for flight. Strong evidence for evolution comes from the analysis of homologous structures: structures in different species that no longer perform the same task but which share a similar structure. Such is the case of the forelimbs of mammals. The forelimbs of a human, cat, whale, and bat all have strikingly similar bone structures.
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The sternum was also lacking in this animal, and the forelimbs were more paddled-shaped, possibly indicating a greater importance of the forelimbs in movement. The pectoral girdle was formed by the paired clavicles, interclavical, scapulae, and coracoids. Keichousaurus was a primitive quadrupedal tetrapod with limbs laterally placed to the body. Different parts of Keichousaurus grew at different rates, a phenomenon called allometric growth.
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The forelimbs of Lisowicia are very distinctive amongst dicynodonts. Indeed, their construction is unique to not only the group, but to non-mammalian synapsids as a whole and shares features with the limbs of mammals and dinosaurs. The forelimbs of Lisowicia are held completely erect under the body, with an elbow joint that is directed backwards and so only allows the forearm to swing forwards and backwards in a parasagittal gait. This arrangement is found in the hindlimbs of various other large Triassic kannemeyeriiforms, but they all retain sprawling forelimbs with elbows bowed outwards and joints that allow the radius and ulna to rotate during each step in a sprawled posture.
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The skull of VMNH 3649 is comparatively larger than that of VMNH 3650, but the forelimbs are shorter. This may be an example of sexual dimorphism.
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New York: Columbia UP, 2000. Academic Search Premier. Web. 1 October 2013. The forelimbs of the jerboa serve as a pair of hands for feeding, grooming, etc.
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It contains the forelimbs, shoulder girdle and sternum. It is partly articulated. Dunhuangia is a medium-sized enantiornithean. The describing authors established some autapomorphies, unique derived traits.
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Their tails are moderately long while male's tails being longer than females. The bodies are covered with multiple yellow stripes including the forelimbs, not the hind limbs.
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A. busacki may attain a maximum snout-to-vent length (SVL) of . Adult males are reddish on the posterior throat, neck, anterior body and belly, and forelimbs.
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Also the pelvis is very long. The tail is short. The forelimbs are very robust, with a large deltopectoral crest on the humerus, indicating a heavy musculature.
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New York: Columbia UP, 2000. Academic Search Premier. Web. 1 Oct. 2013. The forelimbs of the jerboa serve as a pair of hands for feeding, grooming, etc.
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In this case, large-diameter branches pose a greater challenge since the animal cannot place its forelimbs closer to the center of the branch than its hindlimbs.
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Forelimbs in mammals have varying functions but are all homologous. A forelimb is an anterior limb (front arm, front leg, or similar appendage) on a terrestrial vertebrate's body. With reference to quadrupeds, the term foreleg is often used instead. (A forearm, however, is the part of the human arm or forelimb between the elbow and the wrist.) All vertebrate forelimbs are homologous, meaning that they all evolved from the same structures.
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New York: Columbia UP, 2000. Academic Search Premier. Web. 1 Oct. 2013. The forelimbs of the Euphrates Jerboa serve as a pair of hands for feeding, grooming, etc.
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Comparison between Carnotaurus, Dilophosaurus, and Eoabelisaurus forelimbs demonstrating gradual reduction starting at the distal elements Before the discovery of Eoabelisaurus, abelisaurid anatomy was only known from a handful of Late Cretaceous taxa that were aberrant in their morphology, such as their unusual skull structure and reduction of their forelimbs. Eoabelisaurus shows what was previously an unknown stage in the evolution of abelisaurids, having only some of the cranial modifications and a unique combination of features in its forelimbs. The manus of Eoabelisaurus have a derived morphology, with short and robust metacarpals, non-terminal phalanges, and reduced manual unguals. The humerus is unreduced, and the ulna and radius are shortened but do not differ from more basal ceratosaurs.
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"Function in the stunted forelimbs of Mononykus olecranus (Theropoda), a dinosaurian anteater". Paleobiology Vol. 31, No. 3 pp. 373–381. Mononykus is usually reconstructed with a covering of feathers.
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Longicrusavis is a ground dwelling carnivore known from the holotype specimen PKUP V1069, found from the Lower Cretaceous Yixian Formation in Liaoning Province, China., which consists of shale slab and counter slab. The skeleton is nearly complete and belongs to an adult individual, with carbonized feathers preserved in full plumage with visible colouration around the head and forelimbs. Like the closely related genus Hongshanornis, Longicrusavis has hindlimbs that are very long relative to the forelimbs.
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The fingers themselves were fused and immobile, and may have lacked claws. Carnotaurus differed from all other abelisaurids in having proportionally shorter and more robust forelimbs, and in having the fourth, splint-like metacarpal as the longest bone in the hand. A 2009 study suggests that the arms were vestigial in abelisaurids, because nerve fibers responsible for stimulus transmission were reduced to an extent seen in today's emus and kiwis, which also have vestigial forelimbs.
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CT scans and drawings of the skull Ozimek was a small animal, with a length of about . Its limbs were long, with the hindlimbs being generally longer than the forelimbs, and its feet were large. The limbs likely supported a membrane of skin that was used for gliding between trees, much like the similarly proportioned Sharovipteryx. While the forelimbs of the latter are unknown, they were likewise probably similar to those of Ozimek.
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As its forelimbs were roughly half the length of its hindlimbs, Altirhinus appears to have been primarily bipedal. However, its carpals (wrist bones) were thick and blocky, and the three middle fingers of its hand were wide, hyperextendable, and ended in hoof-like bones. This indicates that the forelimbs were also capable of supporting weight. Like many ornithopods, Altirhinus may have spent a significant amount of time in a quadrupedal position, perhaps while feeding.
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The author did not see any forelimbs or pectoral fins. The tail apparently had two fins, the upper fin double the size of the lower fin, much like a shark.
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Springer Verlag. Its marking consist of two rows of elongated dorsal spots. The spots on shoulder, thigh and flank are smaller and darker. Its forelimbs and hindlimbs are not spotted.
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Underside Creamy-white, sometimes with grey mottling along lower jaw on throat and on hind part of abdomen. Thighs and groin often pale yellow. Skin smooth. Forelimbs Arm comparatively short.
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Pederpes is the earliest-known tetrapod to show the beginnings of terrestrial locomotion and despite the probable presence of a sixth digit on the forelimbs it was at least functionally pentadactyl.
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They have extremely short and stubby limbs and the forelimbs are unwebbed. L. laevis is dark olive green with darker blotches outlined in orange. The males have a dark blue throat.
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The forelimbs are moderately short and thin. The fingers are long and have obtusely pointed discs at their tips. Dermal fringes are present. The hind limbs are relatively long and thin.
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The snout is truncate. The tympanum is oval and conspicuous. The forelimbs are thin and long; the hindlimbs are slender and moderately long. The fingers and the toes have fleshy webbing.
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The forelimbs were much shorter than the hindlimbs, ending in hands with 5 digits. Digits IV and V (the ring finger and little finger in humans) were very reduced in size.
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Hand bones of MOR 747 Biomechanical studies by Ken Carpenter in 2002 confirmed that the most likely function of the forelimbs in predation was grasping, as their great lengths would have permitted longer reach than for most other theropods. The rather large and elongated coracoid, indicating powerful muscles in the forelimbs, further strengthened this interpretation. Carpenter's biomechanical studies using bone casts also showed that Deinonychus could not fold its arms against its body like a bird ("avian folding"), contrary to what was inferred from the earlier 1985 descriptions by Jacques Gauthier and Gregory S. Paul in 1988. Studies by Phil Senter in 2006 indicated that Deinonychus forelimbs could be used not only for grasping, but also for clutching objects towards the chest.
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Photograph of specimen and diagram showing plumage Anchiornis is notable for its proportionally long forelimbs, which measured 80% of the total length of the hindlimbs. This is similar to the condition in early avians such as Archaeopteryx, and the authors pointed out that long forelimbs are necessary for flight. Anchiornis also had a more avian wrist than other non-avialan theropods. The authors initially speculated that it would have been possible for Anchiornis to fly or glide.
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Nonetheless, glyptodonts also had powerful forearms. Because the forelimbs did not need to bear weight, it is possible that they dug much like modern armadillos, but the carapace and spine were much more rigid than those of armadillos. Alternatively, the forelimbs may have been engaged while rotating the body to swing the tail club. Because earlier, smaller glyptodonts do not share similar weight distribution, the adoption of a bipedal stance may be related to increasing body size.
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Early genera had long forelimbs, about 60% the length of the hindlimb in Guanlong, with the typical three digits of coelurosaurs. The long forelimb persisted at least through the Early Cretaceous Eotyrannus, but is unknown in Appalachiosaurus. Derived tyrannosaurids have forelimbs strongly reduced in size, the most extreme example being Tarbosaurus from Mongolia, where the humerus was only one-quarter the length of the femur. The third digit of the forelimb was also reduced over time.
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The forelimbs are comparatively short, being only 53% of the hindlimbs' length. This differs greatly from the known skeletal elements of other dromaeosaurids, most of which have relatively long forelimbs that are more than 70% of the hindlimbs' length. While Tianyuraptor is larger in size than all other known microraptorines, it also has relatively elongated lower hindlimbs, like other microraptorines. In this regard, it is different from most other dromaeosaurids, which have relatively short lower legs.
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Restoration Dinocephalosaurus had relatively large legs terminating in flipper-like feet. The forelimbs and hindlimbs are roughly the same length, unlike Tanystropheus where the forelimbs are much smaller. Whereas most protorosaurs, such as Tanystropheus, Macrocnemus, and Langobardisaurus, had relatively ossified limbs adapted for terrestrial life, the stout limbs of Dinocephalosaurus are poorly ossified and resemble those of nothosaurs. Out of the carpal bones, only six are ossified; similarly, only three of the tarsal bones are ossified.
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For example, putative forelimbs discovered in Adelogyrinus and Palaeomolgophis by Brough & Brough (1967) were respectively re-identified as hyoid bones and ribs. Carroll (1967) also claimed that forelimbs were present in Adelospondylus, but these were found to be hyoids as in Adelogyrinus. A few small, elongated scales have been preserved among the bones of the Acherontiscus skeleton. These scales show some similarities to those of microsaurs, but also towards other tetrapods such as the dvinosaurian temnospondyl Trimerorhachis.
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Retrieved on July 1, 2008. Chonecetus closely resembled a modern Mysticeti, with an elongate, streamlined body supporting a pair of paddle-shaped forelimbs, and a horizontal tail fluke strengthened by fibrous cartilage.
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The forelimbs were very powerful. The head was protected by bulbous armour tiles. It could defend itself against predators like Tarbosaurus with a tail-club. On the torso keeled osteoderms were present.
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The hindlimbs and especially the forelimbs were rather elongated. Dal Sasso & Maganuco considered it likely that a coat of primitive protofeathers was present, as these are also known from some direct relatives.
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The forelimbs are long and the hindlimbs are . The femur is long and the tibia is .Xu, Wang and You, 2000. A primitive ornithopod from the Early Cretaceous Yixian Formation of Liaoning.
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Boxer mantis is a common name given to various species of praying mantis. The name comes from the way these mantises move their oversized grasping forelimbs as they communicate with each other.
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The forelimbs are modified into wings. The wings are more or less developed depending on the species; the only known groups that lost their wings are the extinct moa and elephant birds.
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In large genera (such as Dinodontosaurus) the hindlimbs were held erect, but the forelimbs bent at the elbow. Both the pectoral girdle and the ilium are large and strong. The tail is short.
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The pelvis was large with the pubis forming the majority of the ventral portion. The hind limbs of Drepanosaurus were much larger than the forelimbs with the tibia and fibula being broadly separated.
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Adult males measure , subadult males , and subadult females in snout–vent length. The snout is rounded. The tympanum is not very distinct whereas the supratymapnic fold is prominent. Adult males have enlarged forelimbs.
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S. guentheri is known from only one specimen which was collected in 1886.Branch (2004). It has greatly reduced limbs. The forelimbs are entirely lost, and the hind limbs retain only two digits.
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If the tiny front limbs also supported a membrane, they could have acted as a very efficient means of controlling pitch stability, very much like an aeronautic canard. Without a forewing, the authors find, controlled gliding would have been very difficult. Together with the canards on the forelimbs, these anterior membranes may have formed excellent control surfaces for gliding. The area around the forelimbs was completely prepared away in the only known fossil, destroying any possible trace of a membrane there.
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Anchiornithids share many general features with other Paraves and early avialans. They were small and lightly-built feathered carnivores, similar in biology to Archaeopteryx, early dromaeosaurids like Microraptor, and particularly troodontids. They are almost exclusively known from Late Jurassic Chinese deposits, although Ostromia was discovered in Germany and Yixianosaurus (a putative member of the group only known from forelimbs) is believed to hail from the early Cretaceous. Most had long legs, arms, and hands, although some (Eosinopteryx) had slightly reduced forelimbs.
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Goodfellow's tree-kangaroo is slow and clumsy on the ground, moving at about walking pace and hopping awkwardly, leaning its body far forward to balance the heavy tail. However, in trees it is bold and agile. It climbs by wrapping its forelimbs around the trunk of a tree and hopping with the powerful hind legs, allowing the forelimbs to slide. It has extraordinary jumping ability and has been known to jump to the ground from heights of 30 feet without harm .
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Owing to its supposed affinities with Ornithosuchus, Romer reconstructed Gracilisuchus as a facultative biped in his initial description. Both Walker and Bonaparte noted that the forelimbs of ornithosuchids were considerably reduced relative to the hindlimbs, with likewise reduced fingers that were more suitable for grasping than locomotion. Although the hand is not preserved in Gracilisuchus, Romer noted that its forelimbs were three-fifths the lengths of the hindlimbs, like ornithosuchids; however, this interpretation was based on material which has since been reassigned.
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The pelvis and hindlimbs were specialized to stand upright, and to sit for hours while feeding, like the living gelada monkey. Some early paleontologists thought the claws were used to dig up roots and tubers, but their teeth were designed for soft foods, and studies of tooth wear show they ate fruit and seeds. Their forelimbs were specialized to reach, grasp, and strip or sweep plants to the mouth. They could not retract the huge front claws, and knuckle-walked on their forelimbs.
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Dorsal coloration varies between individuals and environmental conditions between dark green to dark purple or violet. The sides, forelimbs, and the loreal and tympanic regions are yellow. The ventrum is yellow to light yellow.
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The body outlines preserved show that Ascendonanus had a plump neck and muscular thighs (although the femur bone itself is relatively thin) on its short hindlimbs, while the trunk and the forelimbs are relatively slender.
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Brunneria borealis is an elongated green insect with the typical raptorial forelimbs of a mantis. The adults have reduced-size wings and are probably unable to fly. They can grow to a length of about .
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The jaw joints were low. There were about twelve, rather large, maxillary or dentary teeth in each upper or lower jaw. The forelimbs were lightly built. The ilium was short and low, the pubis thin.
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The forelimbs are slender. The fingers have weak dermal fringes. The toes have thick webbing and extensive dermal fringing reaching to their tips. Dorsal coloration consists of a light gray background and dark gray spots.
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The tympanum is distinct and rounded, and the canthus rostralis is rounded. The supratympanic fold is distinct. The forelimbs are relatively short. The fingers have no webbing but have well-developed discs at their tips.
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Restoration based on the holotype specimen, NHMUK R5764. Mantellisaurus was a lightly constructed iguanodont. Compared to Iguanodon bernissartensis, Mantellisaurus was smaller, estimated at in weight. Its forelimbs were proportionally shorter than those of I. bernissartensis.
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Adult males measure and adult females in snout–vent length. The snout is subacuminate. The tympanum is small, recessed, and smooth, whereas the tympanic annulus is granular. The forelimbs are slender; fingers are without webbing.
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Scales around the eye are yellow. Two parallel lines along the dorsum starting from the base of forelimbs and terminating near the tail. White crossbands along the dorsum. Limbs brown, mottled with black and white.
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Occasionally it has been recorded to suddenly "faint" on the surface without waking up for several hours until disturbed. Above the ground it moves in a sinuous fashion, using its powerful forelimbs to haul the body over the surface and its hind limbs to push forward. The forelimbs are extended forward in unison with the opposite hind limb. Moles move about the surface with frantic haste but little speed, as one observer once likened it to a "Volkswagen Beetle heaving its way through the sand".
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Specimen NHMUK R3877 was the first to be collected, and consisted of a skull, neck and trunk vertebrae, a shoulder blade, an ischium, and parts of the forelimbs. Specimen NHMUK R3878, was the second to be collected, and includes parts of the pectoral girdle as well as forelimbs. These specimens found represent the most complete remains of Cretaceous pterosaurs in England, more complete than even Ornithocheirus, and specimen NHMUK R3877 was one of the only known three-dimensionally preserved pterosaur skeletons during the 20th century.
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Tyrannosauroids were bipedal carnivores, as were most theropods, and were characterized by numerous skeletal features, especially of the skull and pelvis. Early in their existence, tyrannosauroids were small predators with long, three-fingered forelimbs. Late Cretaceous genera became much larger, including some of the largest land-based predators ever to exist, but most of these later genera had proportionately small forelimbs with only two digits. Primitive feathers have been identified in fossils of two species and may have been present in other tyrannosauroids as well.
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In describing Scansoriopteryx, Czerkas and Yuan also described evidence for an arboreal lifestyle. They noted that, unlike all modern bird hatchlings, the forelimbs of Scansoriopteryx are longer than the hind limbs. The authors argued that this anomaly indicates the forelimbs played an important role in locomotion even at an extremely early developmental stage. Scansoriopteryx has a better-preserved foot than the type of Epidendrosaurus, and the authors interpreted the hallux as reversed, the condition of a backward-pointing toe being widespread among modern tree-dwelling birds.
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On the other hand, the forelimbs were able to retract towards the body very strongly. Once prey had been seized in the jaws, the heavily muscled forelimbs may have retracted, holding the prey tightly against the body and preventing escape. As the prey animal attempted to pull away, it would only have been further impaled on the permanently flexed claws of the first two digits. The extreme hyperextensibility of the digits may have been an adaptation allowing Acrocanthosaurus to hold struggling prey without fear of dislocation.
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Kentrosaurus was a small stegosaur. It had the typical dinosaurian body bauplan, characterised by a small head, a long neck, short forelimbs and long hindlimbs, and a long, horizontal and muscular tail. Typical stegosaurid traits included the elongation and flatness of the head, the powerful build of the forelimbs, erect and pillar-like hindlimbs and an array of plates and spikes running along both sides of the top mid-line of the animal. Only a single complete tooth was known when Hennig published his monography in 1925.
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It has been suggested that the long, powerful forelimbs of Heterodontosaurus may have been useful for tearing into insect nests, similarly to modern anteaters. These forelimbs may have also functioned as digging tools, perhaps for roots and tubers. Tianyulong restoration The length of the forelimb compared to the hindlimb suggests that Heterodontosaurus might have been partially quadrupedal, and the prominent olecranon process and hyperextendable digits of the forelimb are found in many quadrupeds. However, the manus is clearly designed for grasping, not weight support.
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The stark difference in arm length compared to other dromaeosaurids implies that the function of the arms in Tianyuraptor was different from that of other dromaeosaurs. Members of the subfamily Microraptorinae, such as Microraptor, have been suggested to have been aerodynamic and may have glided. Microraptorines are usually noted for their long and robust forelimbs and large, asymmetrical flight feathers. However, the shortened forelimbs, small furcula, and the transversely wide coracoid in Tianyuraptor suggest that it was not suited for aerodynamic gliding or flight.
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The finger and toe tips are expanded to discs; the toes are almost fully webbed. Coloration is dorsally beige with light green flecking; there is pinkish wash on upper sides, forelimbs, and lips. Black spotting is present on the dorsal surface of snout tip, lips, upper eyelids, forelimbs, dorsolateral folds, and flanks. Black streaks run below edge of canthus from tip of snout to eye, obliquely from eye to commisure of jaws, and from eye along supratympanic fold to posterior rim of tympanum, continuing obliquely to shoulder.
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Paravians generally have long, winged forelimbs, though these have become smaller in many flightless species and some extinct lineages that evolved before flight. The wings usually bore three large, flexible, clawed fingers in early forms. The fingers became fused and stiffened and the claws highly reduced or lost in some advanced lineages. An increasingly asymmetric wrist joint, a trend that can be traced back to primitive coelurosaurs, allowed the forelimbs to elongate and an elaboration of their plumage, traits that made the evolution of flapping flight possible.
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Bannykus, along with Xiyunykus, fills a 70-million year gap in alvarezsaur evolution by exhibiting morphologies intermediate between the typical theropod forelimb of Haplocheirus and the highly reduced forelimbs and minute teeth of Late Cretaceous alvarezsaurids.
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The skeletal structure of G. longirostris has been documented, especially the forelimbs by Ryosuke Motani in 1998 and the skull by Ryosuke Motani in 2000 . These studies involved modern documentation and research of previously discovered specimens.
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The face is only thinly furred with white hairs. Thick brown hair is around the neck and between the ears. Its forelimbs are shorter than its hindlimbs. Its vision, auditory, and olfactory senses are very sharp.
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In this view, bipedality and other avian skeletal alterations were side effects of muscle hyperplasia, with further evolutionary modifications of the forelimbs, including adaptations for flight or swimming, and vestigiality, being secondary consequences of two-leggedness.
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The limbs are proportioned similarly to those of living corytophanids in that the hind limbs are long and the forelimbs are short, adaptations that may have made Geiseltaliellus an effective jumper and sprinter like the living Basiliscus.
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The digit formula for Doleserpeton is 4 digits on the forelimbs and 5 digits on the hindlimb. This digit formula is primitive to all living amphibians with a few exceptions in Caecilian and some outlying amphibious species.
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The limbs were proportionally short, as seen in other titanosaurs. The forelimbs measured in height in the nearly complete specimen, approximately two thirds the length of the hindlimbs, which were reconstructed at height. As in other titanosaurs, the limbs were slightly spread outwards rather than standing vertically under the body, while the forelimbs were more flexible and mobile compared to other sauropods. Limbs of Opisthocoelicaudia, showing the digit-less semicircular hands and the fully developed feet The manus was composed merely of the five metacarpalia, which were orientated vertically and arranged in a semicircle.
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Restoration of D. torosus Daspletosaurus shared the same body form as other tyrannosaurids, with a short, S-shaped neck supporting the massive skull. It walked on its two thick hindlimbs, which ended in four-toed feet, although the first digit (the hallux) did not contact the ground. In contrast, the forelimbs were extremely small and bore only two digits, although Daspletosaurus had the longest forelimbs in proportion to body size of any tyrannosaurid. A long, heavy tail served as a counterweight to the head and torso, with the center of gravity over the hips.
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The first of these, NHMUK R3877, was collected as three blocks and consists of a skull, neck and trunk vertebrae, a shoulder blade, an ischium, and parts of the forelimbs. The second specimen, NHMUK R3878, was collected in one block, and includes parts of the pectoral girdle and forelimbs. These specimens represent the most complete remains of Cretaceous pterosaurs found in England, and NHMUK R3877 was one of the only known three- dimensionally preserved pterosaur skeletons for much of the 20th century (pterosaur bones are often flattened compression fossils).
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In 1901, Seeley named the new species as O. latidens, which means "wide tooth". Reginald Hooley later described two more specimens of O. latidens in 1913, which were collected in 1904 from the sea after a rockfall near Atherfield Point on the Isle of Wight. The first of the specimens was collected, and consisted of a skull, neck and trunk vertebrae, a shoulder blade, an ischium, and parts of the forelimbs. The second specimen was collected in just one block, and it includes parts of the forelimbs and pectoral girdle.
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Dorsal side of the forelimbs covered by 2 or 3 large imbricate series of plates edged with black. 28–36 subdigital scales. 10–15 femoral pores are present. Maximum snout-vent-length (SVL) , average tail/SVL ratio = 2.8.
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Compsognathids share a variety of characteristics. The genera in this family demonstrate traits that are characteristic of theropods, such as smaller forelimbs than hind legs. Size, feathers, and metacarpal size are among the most important classifying common characteristics.
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It is also proposed that facultative bipedalism occurred in Mesenosaurus. This is based on the presence of a rearward shift of center of body mass (slender trunks, elongated hindlimbs, and short forelimbs) that is necessary for facultative bipedalism.
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The stegosaurian forelimb has evidence for a sauropod−like metacarpal configuration This was a different evolutionary strategy than megafaunal mammals such as modern elephants. Therapsids started evolving diverse and specialized forelimbs 270 million years ago, during the Permian.
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Marine mammals have evolved several times. Over the course of their evolution, they develop streamlined hydrodynamic bodies. The forelimb thus develops into a flipper. The forelimbs of cetaceans, pinnipeds, and sirenians presents a classic example of convergent evolution.
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Its hind legs had five toes, and were longer than the forelimbs, which had only four toes. Although Keraterpeton had a long body, it did not have more vertebrae than most other amphibian species (15-26 on average).
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There is a distinct black horizontal band, with a red leading edge, at level with the forelimbs. The vocal sac is deep purplish black when calling. The iris is golden yellow with brown mottling. The pupil is black.
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They have large incisors that curve forward and which are used to loosen soil and gnaw through roots, strong forelimbs for digging and powerful hind limbs for moving soil and kicking it out of the entrance to the burrow.
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Xiyunykus, along with Bannykus, fills a 70-million year gap in alvarezsaur evolution by exhibiting cranial and postcranial morphologies intermediate between the typical theropod forelimb of Haplocheirus and the highly reduced forelimbs and minute teeth of Late Cretaceous alvarezsaurids.
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Mirarce eatoni was a large turkey- sized bird. Skeletal morphology indicates that at the time of death, the individual was adult. All the surviving elements of the bones show complete fusion. The bones of the forelimbs deserve special attention.
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They have a layer of fat, or blubber, under the skin to maintain body heat in cold water. Several species exhibit sexual dimorphism. Two external forelimbs are modified into flippers; two internal hindlimbs are vestigial. Cetaceans have streamlined bodies.
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The most common version of the "from the ground up" hypothesis argues that bird's ancestors were small ground-running predators (rather like roadrunners) that used their forelimbs for balance while pursuing prey and that the forelimbs and feathers later evolved in ways that provided gliding and then powered flight. Another "ground upwards" theory argues the evolution of flight was initially driven by competitive displays and fighting: displays required longer feathers and longer, stronger forelimbs; many modern birds use their wings as weapons, and downward blows have a similar action to that of flapping flight. Many of the Archaeopteryx fossils come from marine sediments and it has been suggested that wings may have helped the birds run over water in the manner of the Jesus Christ lizard (common basilisk). Most recent attacks on the "from the ground up" hypothesis attempt to refute its assumption that birds are modified coelurosaurid dinosaurs.
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Regarded as a solitary species, the ground cuscus fights by adopting a bipedal stance and lashing out with the forelimbs whilst emitting hissing and barking vocalisations. In captivity, compatible pairs can be housed together, but periodic fighting may still occur.
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Contact with struggling prey is also the likely cause of tendon avulsions found in the forelimbs of Allosaurus and Tyrannosaurus. The authors concluded that the presence of stress fractures provide evidence for "very active" predation- based diets rather than obligate scavenging.
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Adult males measure and adult females, based on a single specimen only, in snout–vent length. The body is stout and the head is large. There is no tympanum, but the supratympanic fold is distinct. The forelimbs are comparatively long.
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Around three years of age, Rana temporaria temporaria return to the site where they first developed. Males return first and produce a low pitch growling croak to attract mates. A successful mate will wrap his forelimbs around the female in amplexus.
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Nuptial pads absent. Between forelimbs, there is a large, dark brown square-shaped blotch on mid- dorsum. black and white patches are found on anterior and posterior surfaces of thigh and posterior flank. Dorsum light brown with dark brown patches.
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The parotoid glands are elliptical to triangular and overhanging the lateral edges of body. The forelimbs are long and comparatively more robust than the hind limbs. The fingers have no webbing but are slightly fringed. The toes are long and webbed.
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Besides, Caihong was especially distinguished from closely related genera of the Yanliao Biota, such as Eosinopteryx and Anchiornis, by the presence of prominent lacrimal crests, longer pennaceous feathers on the forelimbs and hindlimbs and tail feathers with large asymmetrical vanes.
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Longer forelimbs would be more advantageous when moving through trees that are spaced further apart, making the changes in structure and purpose of the forelimbs due to vertical climbing and brachiation more dramatic. These changes make quadrupedal walking more difficult and contributing to the shift to bipedal locomotion. Gibbons and sifakas are examples of this: their movement through trees makes quadrupedal walking difficult, resulting in bipedal walking and galloping, respectively. Arboreal adaptations making bipedalism advantageous are supported by research that shows that hip and thigh muscles involved in the bipedal walking often most resemble those used in climbing.
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Some of the defining characteristics of Ceratosauria include an increase in height and ornamentation of the skull, as well as a shortening of the forelimbs. Likewise, ceratosaurs fused their ilium, ischium, and pubis together, as well as the astralagus and calcaneum. For less derived members of the group, such as C. nasicornis, traits such as raising of the skull and shortening of the forelimbs were not as noticeable. The skull of C. nasicornis was rather similar to the basal theropod mold, with a distinguishing nasal crest to go along with lacrimal crests similar to the contemporary Allosaurus.
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Tarbosaurus and Tyrannosaurus, if not synonymous, are considered to be at least closely related genera. Alioramus, also from Mongolia, has previously been thought by some authorities to be the closest relative of Tarbosaurus, though this has since been disproven with the discovery of Qianzhousaurus and the description of the Alioramini. Like most known tyrannosaurids, Tarbosaurus was a large bipedal predator, weighing up to and equipped with about sixty large teeth. It had a unique locking mechanism in its lower jaw and the smallest forelimbs relative to body size of all tyrannosaurids, renowned for their disproportionately tiny, two-fingered forelimbs.
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This results in decreased strength in the forelimbs relative to body size for humans compared to apes. Having long hindlimbs and short forelimbs allows humans to walk upright, while orangutans and gibbons had the adaptation of longer arms to swing on branches. Apes can stand on their hindlimbs, but they cannot do so for long periods of time without getting tired. This is because their femurs are not adapted for bipedalism. Apes have vertical femurs, while humans have femurs that are slightly angled medially from the hip to the knee, thus making human knees closer together and under the body’s center of gravity.
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Suspensory locomotion aids with reducing path lengths and covering longer distances by moving faster through branches and trees above. The movements of involved in suspensory behavior can be described as being seen most often among monkeys. The swinging motion of grabbing branch after branch with alternating hands or launching the body from one support to another losing contact with the support is very common and the most popular form of locomotion among suspensory animals. Some animals such as the platyrrhines, use their tails for traveling and usually never use their forelimbs for transportation, while some species use both their tails and forelimbs.
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Two "morphs" of Coelophysis have been identified: a more gracile form, as in specimen AMNH 7223, and a slightly more robust form, as in specimens AMNH 7224 and NMMNH P-42200. Skeletal proportions were different between these two forms; the gracile form has a longer skull, a longer neck, shorter forelimbs, and has sacral neural spines that are fused; and the robust form has a shorter skull, a shorter neck, longer forelimbs, and unfused sacral neural spines. Historically, many arguments have been made that this represents some sort of dimorphism in the population of Coelophysis, probably sexual dimorphism.Gay, R. (2005).
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R. ondatrae’s mechanism of causing malformations is still unknown, but there seems to be evidence in which areas of the body it infects more. Studies show that when frogs or toads are affected with R. ondatrae it seems that the most common spot for any deformity is on the hind limbs. But the amount of exposure to R. ondatrae cercariae appears to determine where a deformity will occur. For instance, a moderate amount of R. ondatrae can affect the forelimbs of amphibians, but a heavy parasite load does not affect the forelimbs and only causes deformities in hind limbs.
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The ability to fly or glide has been suggested for at least five dromaeosaurid species. The first, Rahonavis ostromi (originally classified as avian bird, but found to be a dromaeosaurid in later studies) may have been capable of powered flight, as indicated by its long forelimbs with evidence of quill knob attachments for long sturdy flight feathers. The forelimbs of Rahonavis were more powerfully built than Archaeopteryx, and show evidence that they bore strong ligament attachments necessary for flapping flight. Luis Chiappe concluded that, given these adaptations, Rahonavis could probably fly but would have been more clumsy in the air than modern birds.
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Display of two "fingers" on forelimbs and three toes on hindlimbs The name "two-toed sloth" was intended to describe an anatomical difference between the genera Choloepus and Bradypus, but does so in a potentially misleading way. Members of Choloepus have two digits on their forelimbs (the thoracic limbs) and three digits on their hindlimbs (the pelvic limbs), while members of Bradypus have three digits on all limbs. Although the term "two-fingered" sloth is arguably less misleading, the shorter "two-toed" is much more widely used. Members of Choloepus are larger than three-toed sloths, having a body length of , and weighing .
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The specific name is derived from the Latin bulla, a gold capsule worn by Roman youth around the neck, in reference to the bulbous capsule on the parasphenoid at the base of the dinosaur's skull. Such a feature had not been described from other reptiles at the time, and was considered unusual. The holotype consists of an almost complete skeleton with a distorted snout, incomplete lower jaw, vertebral series, pelvis, as well as some missing hand and foot bones. The other partially complete skeletons were juveniles; ZPAL MgD-I/1 (from Tsaagan Khushuu) has a crushed skull with a missing tip, damaged vertebrae, fragmented ribs, pectoral girdle and forelimbs, and an incomplete left hind limb, ZPAL MgD-I/94 (from the Nemegt locality) lacks the skull, atlas, tip of the tail, pectoral girdle and forelimbs, while the smallest specimen, IGM 100/10 (from Bugeen Tsav), lacks a pectoral girdle, forelimbs and several vertebrae and ribs.
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A buttress above each acetabulum (hip socket) is thought to have prevented dislocation of the femur (thigh bone) while Lystrosaurus was walking with a semi-sprawling gait. The forelimbs of Lystrosaurus were massive, and Lystrosaurus is thought to have been a powerful burrower.
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It has gray underfur. The feet pads are reddish brown, and the forelimbs and hindlimbs are a dull reddish brown. The dense fur is thick and rougher than other rock hares. The flesh is reported to have an odor comparable to urine.
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A large, stoutly build gecko. The size from snout to vent is , plus the tail length of . It has a brown color with five dark brown saddle patches between forelimbs and base of tail. Ventral side light brown with a yellow hue.
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The dorsum has tubercles and a few longitudinal folds. A prominent skin fold overhangs the vent. The forelimbs are slender and moderate in length. The fingers are free of webbing and have rounded tips that are slightly swollen but not disc-like.
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When underwater, its body is long and streamlined, with the short forelimbs pressed closely against the chest.Kenyon, p. 62 When at the surface, it usually floats on its back and moves by sculling its feet and tail from side to side.Love, p.
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It had a short neck and laterally-directed shoulder joint. Its forelimbs were short and powerfully built, and its manus were broad, with fused phalanges. Its hind limbs were flexible and probably could be used to move dirt out of the way.
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Males measure and females in snout–vent length. Head is slightly narrower than body. Forelimbs are moderaterely robust; hind limbs are long and have webbed toes. Ground colour of dorsum is light brown or greenish brown, profusely spotted with minute, black spots.
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Could Sauropods Rear? The weight distribution of Jobaria indicates that it was supported by the rear limbs rather than the forelimbs (as in elephants) and is speculated that as elephants can rear up, then Jobaria would have been able to more easily.
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Tick paralysis is included in avian spirochetosis and appears in the same fashion. The flaccid paralysis ascends throughout the body. Incoordination first occurs followed by paralysis of the hind limbs, forelimbs, and then leads to respiratory distress and failure. Death then follows.
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"Phuwiang spinosaurid B" was calculated as approximately long by Samathi in 2019. As a spinosaurid, Siamosaurus would have had low, narrow, and elongated jaws; well-built forelimbs; relatively short hindlimbs; and elongated neural spines on the vertebrae forming a sail on its back.
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Therizinosaurs probably used their long forelimbs, long necks, and beaks when browsing, and large guts for processing food. Segnosaurus is known from the Bayan Shireh Formation, where it lived alongside the fellow therizinosaurs Erlikosaurus and Enigmosaurus; these related genera were probably niche partitioned.
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The flanks are light brown with dark brown spots. The forelimbs are banded. The venter is light yellow or earthly-yellow; the throat and chest have grayish-brown tiny spinules. The ventral surface of the thigh has deep olive to gray-brown spots.
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Northern bat Nathusius' pipistrelle Bats are members of the order Chiroptera. The most distinguishing feature of bats is that their forelimbs are developed as wings, making them the only mammals capable of flight. Bat species account for about 20% of all mammals.
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The forelimbs are slender with long fingers that have narrow lateral fringes and bear horizontally expanded discs; toes II–IV hase basal webbing. The hind limbs are long. The toe discs are more rounded than the finger discs. The toes are moderately webbed.
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They are hopping rodents of the rocky deserts in Asia. They have been found in Afghanistan, Armenia, Azerbaijan, China, Georgia, Iran, Kazakhstan, Pakistan, Russia, Tajikistan, Turkey, and Turkmenistan. They have long hind feet, short forelimbs, and walk upright.Lagassé, Paul (2000) "Jerboa." in The Columbia Encyclopedia.
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The white-spotted supple skink is found in South Asia. Its body is elongated with weak limbs. The distance between the end of its snout and forelimbs is 2 to 2.5 times the distance between the axilla and groin. The snout is short and obtuse.
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Another notable behavior of the species is occasional bipedal locomotion. It can run relatively quickly on its hind feet for a limited distance. It carries its body in an oblique position, lifting its hindlimbs high. It swings its forelimbs in phase with its hindlimbs, i.e.
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The forelimbs are long whereas the hindlimbs are moderately short. The finger and the toe tips are rounded; the toes have rudimentary webbing. Skin is dorsally very rough and largely covered with tubercles, many of them bearing black spines. Ventral skin is mostly smooth.
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The forelimbs are paddle-like flippers which aid in turning and slowing. Manatees generally glide at speeds of , but can reach speeds of in short bursts. The body is fusiform to reduce drag in the water. Like cetaceans, the hind limbs are internal and vestigial.
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Chatterjee suggested that Postosuchus could walk in an erect stance, since the short forelimbs were probably used only during slow locomotion. In 1995 Robert Long and Phillip A. Murry argued that Postosuchus was heavily built and quadrupedal.Long and Murry (1995), p. 139. Peyer et al.
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Changes in the hind limbs did not affect the location of the forelimbs, which in birds remained laterally spaced, and in dinosaurs they switched to a parasagittal orientation.Kurochkin E. N. Synopsis of Mesozoic Birds and Early evolution of Class Aves // Archaeopteryx. — 1995 b. — 13\.
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According to the arboreal hypothesis, the ancestors of birds climbed trees with the help of their forelimbs, and from there they planned, after which they proceeded to flight.Bogdanovich I. A. Once more about origin of birds and fl ight: “cursorial” or “arboreal”? // Vestnik zoologii. — 2007.
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Cetiosaurus oxoniensis was a "primitive", quadrupedal, long-necked, small-headed herbivore. It had a shorter tail and neck than most sauropods. The forelimbs on the other hand, were relatively long. C. oxoniensis is estimated to have been about long and to have weighed roughly .
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Its forelimbs were remarkably short, and would probably have been held close to the body when swimming to improve the animal's streamlining. Unlike modern crocodilians, it lived in the open ocean, and it probably caught fish and squid with its sharp, needle-like teeth.
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However, the glenohumeral articulation suggests a more conservative forelimb and girdle morphology than that of the pelvic girdle. Evidence points toward a sprawling position of the forelimbs, with an emphasis on long-axis rotation. This likely allowed for manoeuvrability, while the hindlimbs powered the animal.
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In 1877, Zacharias came across a strange monstrosity at a marketplace, a pig with thumbs developed on both forelimbs. Intrigued about the possibility of atavism, he purchased the pig and sent one of the feet to Darwin to ask for his opinion.Burkhardt, Frederick. (2017).
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It possessed long hindlimbs and small forelimbs. Pachycephalosaurus is the largest-known pachycephalosaur. The thick skull domes of Pachycephalosaurus and related genera gave rise to the hypothesis that pachycephalosaurs used their skulls in intra-species combat. This hypothesis has been disputed in recent years.
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The forelimbs are moderately long and slender. The fingers bear large discs and are about one-fourth webbed. The hind limbs are moderately short and slender. The toes are about two-thirds webbed and bear discs that are slightly smaller than those on the fingers.
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II. A dragon with an enormous head and two forelimbs, was claimed to have been encountered by 70-year-old Johannes Egerter of Lienz on Mt. Kamor; when it exhaled its breath, the man said, he was overcome with headache and dizziness., fig. VIII.
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Because of this, the scientists who first studied Tianyuraptor described it as a "transitional species", bridging the gap between northern and southern types of dromaeosaurid. Tianyuraptor also differs from previously known dromaeosaurids in that it possesses a relatively small furcula ("wishbone"), and unusually short forelimbs.
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Deinonychosaurs generally had long, winged forelimbs, though these were smaller in some troodontids. The wings usually bore three large, flexible claws. Most deinonychosaurs seem to have been predatory, though some smaller species especially among the troodontids are known to have been at least omnivorous.
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Adapting to high- browsing could possibly explain the convergence between Azendohsaurus and sauropodomorphs, acquiring similar traits of the neck, forelimbs and spine to perform in similar niches. However, the more sprawling posture of Azendohsaurus probably inhibited high-browsing like that of the fully erect sauropodomorphs.
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Its forelimbs were much more similar to later sauropods than basal sauropodomorphs because they are straight, much more gracile, and the proximal end of the ulna is v-shaped. Unfortunately, no skull or neck of Vulcanodon is known, although it is otherwise very well known.
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He concluded that Therizinosauridae, Deinocheiridae, and Segnosauridae, which all had enlarged forelimbs, represented the same taxonomic group. Segnosaurus and Therizinosaurus were particularly similar, leading Perle to suggest they belonged in a family to the exclusion of Deinocheiridae (today, Deinocheirus is recognized as an ornithomimosaur).
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Medical- dictionary.thefreedictionary.com. Retrieved on 2011-03-17. which affects horses causing hemorrhagic subcutaneous nodules in the head and upper forelimbs, in North Africa, Southern and Eastern Europe, Asia and South America, leading to bleeding from the skin. It is commonly referred to as "Summer bleeding".
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The proportion of left forelimbs of hooved animals suggest a very particular sacrificial practice of animals within the burials. Researchers found that the manner of the burials and the goods contained within were closest in relation to the Óc Eo culture of the Mekong Delta.
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However, research has shown that bipedal locomotion does not increase speed but can increase acceleration. It is also possible that facultative bipedalism is a physical property of the lizard's movement rather than a developed behavior. In this scenario, it would be more energetically favorable to allow the forelimbs to rise with the rotation caused by the lizard's acceleration rather than work to keep the forelimbs on the ground. Recent research has shown that the actual acceleration at which lizards begin to run bipedally is lower than the previous model predicted, suggesting that lizards actively attempt to locomote bipedally rather than passively allow the behavior to occur.
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The locomotion of the elephant (which is the largest terrestrial vertebrate) displays a similar loading distribution on its hind limbs and forelimbs. The walking and running gaits of quadrupeds and bipeds show differences in the relative phase of the movements of their forelimbs and hind limbs, as well as of their right-side limbs versus their left-side limbs. Many of the aforementioned variables are connected with differences in the scaling of body and limb dimension as well as in patterns of limb coordination and movement. However, little is understood concerning the functional contribution of the foot and its structures during the weight-bearing phase.
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The limbs of Eohupehsuchus are similar to those of other hupehsuchians in the large size ratio of the distal elements (including the phalanges, the metacarpals and carpals in the forelimbs, and the metatarsals and tarsals in the hindlimbs) to the proximal elements (the radius and ulna in the forelimbs, and the tibia and fibula in the hindlimbs). This is a common feature of secondarily aquatic tetrapods in general, in which the limbs are adapted for steering and/or propulsion through water rather than walking and supporting the body against unidirectional gravity in a terrestrial environment.Motani R (2009) The evolution of marine reptiles. Evolution: Education and Outreach 2: 224–235.
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These hopping rodents can reach a speed up to 48 km/hr. The forelimbs of the jerboa serve as a pair of hands for feeding, grooming, etc.Kirmiz, John P. (1962) Adaptation to Desert Environment; A Study on the Jerboa, Rat and Man. London: Butterworths. p. 29.
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Cats have retractile claws, slender muscular bodies and strong flexible forelimbs. Their teeth and facial muscles allow for a powerful bite. They are all obligate carnivores, and most are solitary predators ambushing or stalking their prey. Wild cats occur in Africa, Europe, Asia and the Americas.
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Dalinghosaurus longidigitus fossil displayed in Hong Kong Science Museum Dalinghosaurus had extremely long tails and hindlimbs relative to its forelimbs. The claws are relatively slender. Eleven specimens of Dalinghosaurus are held by the IVPP in Beijing. One fossil skeleton contains the skeletons of ten or more juveniles.
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Contrary to its elongated forelimbs, Nyctosaurus had proportionally short hindlimbs compared to the overall body size. Analyses show that Nyctosaurus had the shortest hindlimbs of any pterosaur genera, in terms of hindlimb-to-body ratio, which was only about 16 percent the size of its wing.
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The belly is creamish and laterally bordered with blackish spots and a line of white glandular tubercles. A pair of reddish warts are located below and above the vent. The forelimbs have cross-bands and hind limbs black bands. The iris has fine dark network or reticulation.
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Modern scientists, by comparing Megalosaurus with its direct relatives in the Megalosauridae, were able to obtain a more accurate picture. Megalosaurus was about , weighing about . It was bipedal, walking on stout hindlimbs, its horizontal torso balanced by a horizontal tail. Its forelimbs were short, though very robust.
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Anserimimus ( ; "goose mimic") is a genus of ornithomimid theropod dinosaur, from the Late Cretaceous Period of what is now Mongolia. It was a lanky, fast- running animal, possibly an omnivore. From what fossils are known, it probably closely resembled other ornithomimids, except for its more powerful forelimbs.
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The center of mass lies near the pelvic bone, meaning the creature was bipedal. The forelimbs were shorter than the hindlimbs. The hands had three movable digits while the fourth digit was embedded. It had well-developed claws. The juvenile fossils’ estimated height is from about long.
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The caudal vertebrae are lightened by spongeous bone. The forelimbs are rather long because of an elongated slender manus. The humerus is bowed outwards to an exceptionally large extent and has a very rounded head. The first metacarpal is very short and carries a strongly diverging thumb.
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The fossil record shows that the Langobardisaurus featured short forelimbs dwarfed by much longer, hollow hind limbs. The tibia and fibula elements were slightly shorter than the femur. Moving distally, the tarsi were small and compact. These facts suggest that the Langobardisaurus was capable of bipedal locomotion.
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In the Yixian Formation, Zhenyuanopterus lived with other pterosaurs such as Boreopterus, Feilongus, Haopterus, Yixianopterus, and Gegepterus. Teng and colleagues suggested in 2014 that Zhenyuanopterus spent less time on land and more time in the air or on cliffs, owing to the robust forelimbs and weak hindlimbs.
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If the case is extreme enough, such as capture, it is capable of caudal autotomy, or tail separation. Its speed and agility are major contributors to its predatory success as well as its ability to evade predators. When running at rapid speeds it runs with forelimbs raised.
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Long-finned pilot whale Harbour porpoise The order Cetacea includes whales, dolphins and porpoises. They are the mammals most fully adapted to aquatic life with a spindle-shaped nearly hairless body, protected by a thick layer of blubber, and forelimbs and tail modified to provide propulsion underwater.
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Canadian Journal of Earth Sciences, 47(9), 1159-1181. dating to ~68.5 million years ago. Albertonykus is interpreted as having fed on wood-nesting termites because the forelimbs appear specialized for digging, but are too short for burrowing. Albertonykus is the earliest-known North American alvarezsaurid.
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The hindlimbs were much larger than the forelimbs, and in the pelvis the ilium lacked a bony connection to the vertebral column (a classic feature of aquatic tetrapods). The tail, only known from a few vertebrae fragments, is assumed to have been long and laterally compressed.
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However, individuals seem to forage alone, showing none of the day-range group associations. The boodie is nocturnal, sheltering during the day in burrows and foraging widely at night for food. Locomotion is mainly with the hind legs. The forelimbs are used for support when the boodie is stationary.
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The upper portion of the stay apparatus in the forelimbs includes the major attachment, extensor and flexor muscles and tendons. The same portion in the hind limbs consists of the major muscles, ligaments and tendons, as well as the reciprocal joints of the hock and stifle.Harris, p. 253.
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Hadrosaurids had slim hands with short fingers, making their forelimbs ineffective for propulsion, and the tail was also not useful for propulsion because of the ossified tendons that increased its rigidity, and the poorly developed attachment points for muscles that would have moved the tail from side to side.
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Some salamanders have fewer digits and the amphiumas are eel-like in appearance with tiny, stubby legs. The sirens are aquatic salamanders with stumpy forelimbs and no hind limbs. The caecilians are limbless. They burrow in the manner of earthworms with zones of muscle contractions moving along the body.
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The digits have toepads which overlap the first phalange. Both sexes have a large dewlap which extends to behind the forelimbs. The dewlap has two to five (usually three or four) longitudinal rows of minute granular scales separated by bare skin. The colouring of this lizard is variable.
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Overall colouration is light yellowish- brown, with noticeably darker head. Lateral surfaces are more strongly yellow- tinged than dorsum. Exposed surfaces of forelimbs are yellowish-brown proximally and becoming medium brown distally. Exposed surfaces of hindlimbs are relatively uniform yellowish brown, but digits are lighter, tending towards off-white.
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Some small maniraptorans such as scansoriopterygids are believed to have used their forelimbs to climb in trees. The wings of modern birds are used primarily for flight, though they are adapted for other purposes in certain groups. For example, aquatic birds such as penguins use their wings as flippers.
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In four-legged animals, the radius is the main load-bearing bone of the lower forelimb. Its structure is similar in most terrestrial tetrapods, but it may be fused with the ulna in some mammals (such as horses) and reduced or modified in animals with flippers or vestigial forelimbs.
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This posture is also seen in ankylosaurs, ceratopsians, and the early cynodont Procynosuchus. Several aspects of the forelimbs have been interpreted as adaptations to digging. Like many digging tetrapods, the radius is significantly shorter than the humerus. Like other aetosaurs, there is a prominent deltopectoral crest on the humerus.
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The use of the robust forelimbs and giant claws of spinosaurs remains a debated topic. Charig and Milner speculated in 1986 that Baryonyx may have crouched by the riverbank and used its claws to gaff fish out of the water, similarly to grizzly bears. In 1987, British biologist Andrew Kitchener hypothesized a use in scavenging carcasses, though this has been critiqued by other researchers who pointed out that in most cases, a carcass would have already been largely emptied out by its initial predators. A 2005 study by Canadian paleontologist the François Therrien and colleagues posited that spinosaur forelimbs were probably used for hunting larger prey items, given that their snouts could not resist the bending stress.
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The principle of homology: The biological relationships (shown by colours) of the bones in the forelimbs of vertebrates were used by Charles Darwin as an argument in favor of evolution. In biology, homology is similarity due to shared ancestry between a pair of structures or genes in different taxa. A common example of homologous structures is the forelimbs of vertebrates, where the wings of bats and birds, the arms of primates, the front flippers of whales and the forelegs of four-legged vertebrates like dogs and crocodiles are all derived from the same ancestral tetrapod structure. Evolutionary biology explains homologous structures adapted to different purposes as the result of descent with modification from a common ancestor.
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In 1988, paleontologist Gregory S. Paul suggested that the neck of Brachiosaurus was shorter than that of Giraffatitan, but in 2009, paleontologist Mike P. Taylor pointed out that two cervical vertebrae likely belonging to Brachiosaurus had identical proportions. Unlike Giraffatitan and other sauropods, which had vertically oriented forelimbs, the arms of Brachiosaurus appear to have been slightly sprawled at the shoulder joints, as indicated by the sideward orientation of the joint surfaces of the coracoids. The humerus was less slender than that of Giraffatitan, while the femur had similar proportions. This might indicate that the forelimbs of Brachiosaurus supported a greater fraction of the body weight than is the case for Giraffatitan.
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In their 1997 article, Charig and Milner rejected this hypothesis, pointing out that in most cases, a carcass would have already been largely emptied out by its initial predators. Later research has also ruled out this sort of specialized scavenging. In 1986, Charig and Milner suggested that the robust forelimbs and giant thumb claws would have been Baryonyx's primary method of capturing, killing, and tearing apart large prey; whereas its long snout would have been used mostly for fishing. A 2005 study by Canadian paleontologist the François Therrien and colleagues agreed that spinosaur forelimbs were probably used for hunting larger prey items, given that their snouts could not resist the bending stress.
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Mesopropithecus is an extinct genius of small to medium-sized lemur, or strepsirrhine primate, from Madagascar that includes three species, M. dolichobrachion, M. globiceps, and M. pithecoides. Together with Palaeopropithecus, Archaeoindris, and Babakotia, it is part of the sloth lemur family (Palaeopropithecidae). Once thought to be an indriid because its skull is similar to that of living sifakas, a recently discovered postcranial skeleton shows Mesopropithecus had longer forelimbs than hindlimbs—a distinctive trait shared by sloth lemurs but not by indriids. However, as it had the shortest forelimbs of all sloth lemurs, it is thought that Mesopropithecus was more quadrupedal and did not use suspension as much as the other sloth lemurs.
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Monotreme eggs are retained for some time within the mother and receive nutrients directly from her, and they generally hatch within 10 days after laying, much shorter than the incubation period of sauropsid eggs. Newborn monotremes, called "puggles", are larval and fetus- like, much like newborn marsupials (and perhaps all non-placental mammals), and like them have relatively well-developed forelimbs that enable them to crawl around. In fact, because monotremes lack nipples, their puggles crawl about more frequently than marsupial joeys in search of milk; this difference raises questions about the supposed developmental restrictions on marsupial forelimbs. Monotremes lactate from their mammary glands via openings in their skin, rather than through nipples.
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Enaliarctos has been heralded as the ancestor of all known pinnipeds, including the families Otariidae (fur seals and sea lions), Desmatophocidae (extinct seal convergent pinnipeds), Phocidae (true seals), and Odobenidae (walruses). Investigations of the biomechanics of Enaliarctos indicate that it used both its forelimbs and hindlimbs during swimming. Modern fur seals and sea lions only use their forelimbs, while true seals primarily use their hindlimbs for aquatic propulsion; lastly, the extant walrus uses both fore- and hindlimbs for swimming. It has been postulated that the condition in Enaliarctos is ancestral for all pinnipeds, and that forelimb swimming was lost in true seals, while hindlimb swimming was lost in fur seals and sea lions.
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Upper/front limbs of (top) salamander, sea turtle, crocodile, bird, (bottom) bat, whale, mole, and human The skeletons of all mammals are based on a common pentadactyl ("five- fingered") template but optimised for different functions. While many mammals can perform other tasks using their forelimbs, their primary use in most terrestrial mammals is one of three main modes of locomotion: unguligrade (hoof walkers), digitigrade (toe walkers), and plantigrade (sole walkers). Generally, the forelimbs are optimised for speed and stamina, but in some mammals some of the locomotion optimisation have been sacrificed for other functions, such as digging and grasping. In primates, the upper limbs provide a wide range of movement which increases manual dexterity.
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These evolved into the sauropods which became gigantic quadrupedal herbivores, some of which reached lengths of at least 26 m (85 ft). Features defining this clade include a ratio of forelimb length to hindlimb length greater than 0.6. Most sauropods still had hindlimbs larger than forelimbs; one notable exception is Brachiosaurus whose long forelimbs suggest that it had evolved to feed from tall trees like a modern-day giraffe. Sauropod fossils are found from the times of the earliest dinosaurs right up to the Cretaceous–Paleogene extinction event, from 227 to Ma. Most sauropods are known from the Jurassic, to be more precise between 227 and 121 Ma. The Cretaceous sauropods form two groups.
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The species name is appropriate because whales have no hind limbs, only forelimbs shaped like flippers, and so does this species of skink. It also lacks pigmentation as Moby Dick did. The type series consists of two specimens that measured in snout–vent length. The body is about wide at midbody.
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However, researchers have measured this marsupial traveling 2.2 km searching for food. One individual tracked on Barrow Island traveled 5 km. B. lesueur uses scent to locate food, which it digs up with the claws on its strong forelimbs. The boodie will even climb into low shrubs to find food.
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The hands were proportionally the shortest of any ornithomimosaur and each had three digits with curved claws. The forelimbs were weak while the hindlimbs were proportionally long. The family Ornithomimidae is part of the group Ornithomimosauria. Anserimimus, also from Mongolia, is thought to have been the closest relative of Gallimimus.
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The holotype of Aeolosaurus rionegrinus consists of a series of seven tail vertebrae, as well as parts of both forelimbs and the right hindlimb. It was discovered in the Angostura Colorada Formation in Argentina, which dates from the Campanian stage of the Late Cretaceous, about 83 to 74 million years ago.
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The forelimbs were very short, but remained fully functional; the hand had four fingers. The tail was deep from top to bottom. A row of small osteoderms (skin bones) was present down the middle of the neck, back, and tail. Additional osteoderms were present at unknown positions on the animal's body.
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ROM 788 is a tail club. ROM 813 is a skeleton lacking the skull but containing the entire rump, forelimbs and hindlimbs. Apart from a large number of osteoderms, it preserves skin impressions. It has been secured on three blocks that have not been fully prepared to conserve the impressions.
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It can be distinguished from Drepanosaurus, Megalancosaurus and possibly Dolabrosaurus in the lack of a terminal spine at the end of the tail. In addition, Vallesaurus also differs from Hypuronector, a related drepanosaur, in having anteroposteriorly extended neural spines of the anterior dorsal vertebrae and forelimbs much shorter than the hindlimbs.
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Epipedobates machalilla has a snout–vent length of for males and for females. Their heads are longer than they are wide, and the tympanum is small. The forelimbs have a moderate length and the fingers are unwebbed. The toes do not have lateral fringes and the terminal discs are expanded.
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When boxer mantises encounter one another, they rapidly tremble their forelimbs, displaying the patterned interior faces to each other and waving them in slow arcs. This is believed to be a way of preventing member of the same species from eating each other.Alien Insect: Praying Mantis, 2004, by Discovery Channel.
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Alvarezsauridae is a family of small, long-legged dinosaurs. Although originally thought to represent the earliest known flightless birds, a consensus of recent work suggests that they evolved from an early branch of maniraptoran theropods. Alvarezsaurids were highly specialized. They had tiny but stout forelimbs, with compact, bird-like hands.
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The tympanum is visible. Skin of head, dorsum, flanks, and hind limbs strongly and uniformly tuberculate, while skin of forelimbs and ventral surfaces is smooth. The fingers and toes have small discs but no webbing or lateral fringes. The head, dorsum, and flanks are dark pinkish brown, without any markings.
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The forelimbs were proportionally longer than the hindlimbs. Elongated but robust tarsal and carpal bones indicate a cursorial locomotion for the genus. The cervical vertebra are also elongate, and particularly so in P. magnum, giving Palaeotherium a relatively long neck. Palaeotherium exhibits a selenolophodont dentition, with high crowned cheek teeth.
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Birds are generally digitigrade animals (toe-walkers), which affects the structure of their leg skeleton. They use only their hindlimbs to walk (bipedalism). Their forelimbs evolved to become wings. Most bones of the avian foot (excluding toes) are fused together or with other bones, having changed their function over time.
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A gap divided the tusks from the chisel-like cheek-teeth. The body was short with a long tail. The five-fingered forelimbs were long and relatively robust, whereas the hind-limbs were long, slender, and had four toes. Heterodontosaurus is the eponymous and best-known member of the family Heterodontosauridae.
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During the reproductive period, adult males have black, horny nuptial spines on their chest and forelimbs. The fingers are not webbed. The toes are long and webbed to their tips, although the webbing is strongly incurved between the toes. Preserved individuals are greyish above and have warts with blackish spots.
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Behind the protruding eyes and above the tympanum, there is short, small gland. It does not have parotid glands. The underside is white, and around the pelvis yellowy orange. In the mating season, males develop dark swellings on the insides of their digits and forelimbs, as well as on the chest.
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The carpals, metacarpals, and digits of Doleserpeton were allowed for full mobility of its forelimbs and joints to travel on land while providing adequate support for its body mass and size.Sigurdsen, Trond, and John R. Bolt. "The Lissamphibian Humerus and Elbow Joint, and the Origins of Modern Amphibians." Journal of Morphology.
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The species has a broad, flat, snout and head, and vestigial eyes beneath that are covered by skin. Like other neotenous salamanders, it has external gills for absorbing oxygen from the water. The salamander's mature length is around . The forelimbs carry four digits and the hind limbs possess five digits.
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Benton, 2005. Vertebrate Palaeontology 3rd edition. Blackwell Publishing Its peculiar stunted forelimbs were tiny and the humerus was only 35 mm long (the whole animal was about 1.5 m long). Various foramina on the humeral surfaces are very similar to those seen in Ichthyostega, Acanthostega, and lobe-finned fishes like Eusthenopteron.
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These turtles reach sexual maturity sometime between 4 and 6 years of age. They mate at the surface or under water. A male will hold the female's carapace with its forelimbs and may bite at her head, neck, and limbs. Females may retain sperm for almost a year after copulation.
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Bunch grass lizards are typically grey in color, often with orange and yellow coloration around the neck and behind the forelimbs. Males will have more of this vibrant coloration on their underside while female undersides tend to be white. Adults range from 52–62 mm snout-to- vent length (Ortega and Barbault, 1986).
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The forelimbs of Herrerasaurus were less than half the length of its hind limbs. The upper arm and forearm were rather short, while the manus (hand) was elongated. The first two fingers and the thumb ended in curved, sharp claws for grasping prey. The fourth and fifth digits were small stubs without claws.
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Reconstructed skeleton Like other early neornithischians, Kulindadromeus was a bipedal runner, approximately 1.5 meters in length. It had a short head, short forelimbs, long hindlimbs and a long tail. The describers of Kulindadromeus established some distinguishing traits. The front ascending branch of the maxilla is much lower than the rear ascending branch.
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As with all marsupials, the young are born while at the embryonic stage, weighing only . However, they have relatively well- developed lips, forelimbs, and shoulders, as well as functioning respiratory, digestive, and urinary systems. The joey crawls into its mother's pouch to continue the rest of its development.Martin and Handasyde, pp. 60–61.
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It is lightly built and toothless, with a short mouth and robust premaxillae presumably possessing a horny beak. These characteristics are similar to those of Confuciusornis. The forelimbs, though incomplete, are generally similar to those of Archaeopteryx. The sternum is large and unkeeled, but possesses an expanded middle posterior portion and gastralia.
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Skull of the juvenile specimen ELDM V1001 The knowledge of specimens representing various different ages has allowed paleontologists to determine the ontogeny, or change during growth, of this species. During growth the lower legs, feet, ilia and forelimbs became relatively smaller. The skull, on the other hand, grew more robust and deeper.
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Additional specimens, which include vertebrae, forelimbs, hips, hindlimbs, were later described in 2017 from the Belly River Group of Alberta, Canada. They were referred to Qiupalong sp., given that they occurred up to 10 million years before the type material of Qiupalong. These finds suggest that Qiupalong radiated to Asia from Canada.
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The forelimbs are smaller and more gracile than the hindlimbs, suggesting that the center of mass for Tanystropheus was closer towards the pelvic girdle. Attachment sites for the m. caudofemoralis muscle complex, coupled with soft- tissue preservation of relative muscle size, further support the proposition that Tanystropheus was a fairly bottom-heavy animal.
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Pantydraco was of moderate build. The creature had a long tail that tapered towards the end and was broad at the hip joint. It had a pointed head with a strong jaw. The forelimbs of the dinosaur were developed for grasping while the hindlimbs were adapted for supporting the creature's body weight.
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Bennett's tree-kangaroo mother and baby Like other tree-kangaroos it has longer forelimbs and shorter hindlimbs than terrestrial kangaroos and a long bushy tail. It is mostly dark brown above and lighter fawn on chin, throat and lower abdomen. The forehead and muzzle are greyish. The feet and hands are black.
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D. spurensis compared to a human Desmatosuchus was a large quadruped upwards of 4.5 meters in length. Its vertebral column had amphicoelus centra and 3 sacral vertebrae. The scapulae had large acromion processes. The forelimbs were much shorter than the hindlimbs, with humeri less than two-thirds the length of the femurs.
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Ledumahadi was likely a quadruped, as determined by analysis of the circumference of its humerus and femur compared to those of other dinosaurs. It would have had very large, robust forelimbs, consistent with those of its relatives. Unlike those of later sauropods, these limbs were naturally flexed, as opposed to being purely columnar.
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However, the femora are straight in Kentrosaurus, as opposed to typical bipeds, indicating a straight and vertical limb position. Thus, the hindlimbs, though powered by massive thigh muscles attached to a long ilium, did not support the animal alone, and the very robust forelimbs took up 10 to 15% of the bodyweight.
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The female fly cements individual eggs onto hairs of the forelimbs and shoulders of horses, mules and donkeys. Each female lays up to 1000 eggs. In order the hatch, the eggs must be licked by the host animal. If taken into the host's mouth during grooming, the egg will hatch in the mouth.
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The forelimbs were short (hence the specific name), and the hindlimbs were long in comparison. The scutes were extensive. Most of the scutes were keeled, but did not have spikes. Erickson regarded Wannaganosuchus as a generalized early alligatorid closer to the line leading to modern alligatorids than other more specialized early alligatorids.
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The forelimbs were robustly builtSereno, P.C. (2012). pp. 114–132. and proportionally long, measuring 70% of the length of the hind limbs. The radius of the forearm measured 70% of the length of the humerus (forearm bone). The hand was large, approaching the humerus in length, and possessed five fingers equipped for grasping.
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These changes in structure have produced forelimbs adapted for different tasks. bird and the bat wing are examples of convergent evolution. However, anatomical comparisons can be misleading, as not all anatomical similarities indicate a close relationship. Organisms that share similar environments will often develop similar physical features, a process known as convergent evolution.
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All stegosaurians are quadrupedal, with hoof- like toes on all four limbs. All stegosaurians after Huayangosaurus have forelimbs much shorter than their hindlimbs. Their hindlimbs are long and straight, designed to carry the weight of the animal while stepping. The condyles of the lower thighbone are short from the front to the rear.
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The light brown stripes makes the snout region appear like a light grey triangle. The iris is golden above and light golden below and is separated by brown, horizontal band. Dark grey cross bands on the dorsal side of forelimbs and hind limbs. Tip of the snout has a triangular white spot.
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Sharovipterygidae is a family of strange gliding protorosaurians from the mid- Triassic of Eurasia, notable for their short forelimbs and long, wing-like hindlimbs, which supported membranes for gliding. They are represented by Sharovipteryx and Ozimek volans. A 2019 phylogenetic analysis suggested that Ozimek, and by extension Sharovipteryx, may belong to the Tanystropheidae.
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Chimpanzees have lower limbs that are specialized for manipulation, and (arguably) have fingers on their lower limbs as well. The term 'finger' is not applied to the digits of most other animals, such as canines, felines, or ungulates, none of which can engage in fine manipulation with their forelimbs as a primate can.
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Mounted P. mongoliensis skeleton casts in upright and crouching poses Studies by Phil Senter in 2007 conducted on P. neimongoliensis and P. mongoliensis concluded that the forelimbs of these taxa (and likely those of other Psittacosaurus species) were too short (only about 58% as long as the hindlimbs) to reach the ground, and their range of motion indicates they could neither be pronated nor generate propulsive force for locomotion, suggesting that Psittacosaurus was entirely bipedal. The forelimbs were also too short to be used in digging or bringing food to the mouth, and Senter suggested that if Psittacosaurus needed to dig depressions in the ground it may have used its hindlimbs instead. The forelimbs could be used for two-handed grasping of objects or scratching the body, but due to their extremely limited flexibility and reach, they could have only been used to grasp objects very close to the belly or sides of the animal and could have scratched only the belly, flank and knees. Even though the hands could not reach the mouth, Psittacosaurus could have still used them to carry nesting material or food to a desired location.
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Natural History Museum, London, showing an outdated quadrupedal pose Although long assumed to have been quadrupedal, a 2007 anatomical study of the forelimbs has questioned this, arguing that their limited range of motion precluded effective habitual quadrupedal gait. Neither could the forelimbs swing fore and behind in a fashion similar to the hindlimbs, nor could the hand be rotated with the palmar surfaces facing downwards. This inability to pronate the hand is also supported by in-situ finds of articulated (still-connected) arms that always show unrotated hands with palmar faces facing each other. The study also ruled out the possibility of "knuckle-walking" and other forms of locomotion that would make an effective locomotion possible without the need to pronate the hand.
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So, using river otters as a model, Ambulocetus was possibly a pelvic paddler—swimming with alternating beats of the hindlimbs (without engaging the forelimbs)—and also undulated (move up and down) its tail while swimming. Like otters, its spine, particular the thoracolumbar series, was probably also undulating while swimming, so swimming was powered by both the tail and the torso. The pelvis and robust forelimbs have been used to argue that Ambulocetus was capable of weight transfer (walking) on land, and was more efficient at doing this than remingtonocetids and protocetids (it is unclear if the two latter taxa were capable of bearing weight on the limbs). Ambulocetus possibly used a sprawling gait on land, similar to modern sea lions.
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If Deinonychus had feathered fingers and wings, the feathers would have limited the range of motion of the forelimbs to some degree. For example, when Deinonychus extended its arm forward, the 'palm' of the hand automatically rotated to an upward-facing position. This would have caused one wing to block the other if both forelimbs were extended at the same time, leading Senter to conclude that clutching objects to the chest would have only been accomplished with one arm at a time. The function of the fingers would also have been limited by feathers; for example, only the third digit of the hand could have been employed in activities such as probing crevices for small prey items, and only in a position perpendicular to the main wing.
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The modern version of the "from the ground up" hypothesis argues that birds' ancestors were small, feathered, ground-running predatory dinosaurs (rather like roadrunners in their hunting styleCretaceous tracks of a bird with a similar lifestyle have been found - ) that used their forelimbs for balance while pursuing prey, and that the forelimbs and feathers later evolved in ways that provided gliding and then powered flight. The most widely suggested original functions of feathers include thermal insulation and competitive displays, as in modern birds. All of the Archaeopteryx fossils come from marine sediments, and it has been suggested that wings may have helped the birds run over water in the manner of the Jesus Christ Lizard (common basilisk).Videler, J.J. 2005: Avian Flight.
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They have curved claws on their forelimbs and soft pads on their hind limbs that aid in their climbing ability, and they have some independent movement of their digits as well as good dexterity due to their forelimbs being able to bend a great deal. The 4th and 5th digit of their feet are enlarged, the 1st digit is absent, and the 2nd and 3rd digits are syndactylous (two digits that look like one fused together). Scientists have discovered that the Matschie's are able to walk bipedally and there's a lot of rotation in their limbs for climbing. Out of all of the Dendrolagus species, the Matschie's tree-kangaroo is the best vertical climber and has more strength in its muscles than any others.
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Like all gibbons, the silvery gibbon lacks an external tail, has dorsally placed scapulae, and reduced flexibility in its lumbar region. It has long, curved fingers and very long forelimbs relative to its hind limbs. On average, it reaches in weight. It is diurnal and arboreal, climbing trees skilfully and brachiating through the forests.
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Pademelons are small marsupials of the genus Thylogale. Pademelons are some of the smallest of the family Macropodidae. The word ‘macropod’ means ’big foot’ which is a common trait found in marsupials. Most Macropods share the characteristics of hind legs larger than their forelimbs, large hind feet, and long muscular tails used for balance.
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It has gray or grayish white, dense underfur. It has a medium-sized tail which is completely white for that occurring in the Shoa Province, and white with a mid-dorsal black stripe for that occurring in the Bale Mountains. The feet are densely padded with brown hairs. The forelimbs are long, pale cinnamon colored.
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As a dromaeosaurid, Pyroraptor likely had well-developed forelimbs with curved claws, and probably balanced the body with a long, thin tail. Pyroraptor was also likely covered in feathers, as many of its relatives, like Microraptor and Sinornithosaurus, also had plumage.Scott Sampson in Discovery Channel's 2003 documentary series Dinosaur Planet, ep. 2: "Pod's Travels".
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The holotype skeleton includes a crushed skull preserved in dorsal or top view, and a straight length of vertebrae and associated ribs that are poorly preserved. The forelimbs and parts of the pectoral girdle are also preserved. The hind limbs and tail are missing. Altenglanerpeton has a robust skull with small, widely spaced eye sockets.
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These flukes are raised up and down in long strokes to move the animal forward, and can be twisted to turn. The forelimbs are paddle-like flippers which aid in turning and slowing. The dugong lacks nails on its flippers, which are only 15% of a dugong's body length. The tail has deep notches.
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It is the largest species in the genus Pelusios, with a carapace length of up to 55 cm. Females are larger than males. Males can also be distinguished by their slightly longer tails. For defence, the hinged plastron closes to protect the head and forelimbs, and the terrapin also secretes a foul odour when threatened.
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The chest is large and flat rather than barrel-shaped. The belly is strong and drawn in. The back is short and slightly sloped; the tail is high set, and when freely lowered reaches the tarsi. The forelimbs are straight and narrow- set, with the paws slightly turned out, with a long radius and metacarpus.
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Brain, Behavior and Evolution 73(2): 138-149. The two techniques they use for digging are scratch- digging and skull-tooth digging. A combination of the two methods are often used. Their claws and forelimbs are used primarily for scratch-digging, and their skull and incisor teeth are used secondarily for skull-tooth digging.
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The canthus rostralis is distinct, as is the tympanum. The forelimbs are comparatively long and very stout; the fingers have rounded tips and slight basal webbing. The hind limbs are moderately long; the toes have rounded tips and poorly developed webbing. The dorsal ground color varies from light orange brown to dark chocolate brown.
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When swimming on the surface, otters row with the forelimbs and paddle with the hind limbs. When diving under water, they undulate their bodies and tails. Captive otters swim at speeds of . Observations of wild Asian small- clawed otters revealed that they smear their spraint at latrine sites, using their hind feet and tails.
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Adult males measure and adult females in snout–vent length. The snout is rounded in dorsal view and truncate in profile. The supratympanic fold is thin but covers the upper edge of the tympanum. The forelimbs are moderately robust; the fingers are moderately long, have large discs, and are less than one-fourth webbed.
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The mantis turns to face the aggressor, rears up by arching its back, curls its abdomen upwards (dorsiflexion), raises and waves its forelimbs, raises its wings to displays the large brightly coloured eyespots on the hindwings, and stridulates by scraping the edge of its hindwings against its tegmina, the leathery front wings.Prete, 1999. p 185.
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When you extend their hind legs you can see that only on their thighs they do not have the pattern continued but rather just a pale yellow color.Cope 1874 The hourglass tree frog has relatively large forelimbs in comparison to the proportion of its body. It has well developed toe discs for tree climbing.
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The forelimbs were longer than the hindlimbs, in contrast to the more derived sauropods. It has been calculated around 9-10 m long.Redelstorff, R. A. G. N. A., Sander, P. M., & Galtom, P. M. (2013). Unique bone histology in partial large bone shafts from Aust Cliff (England, Upper Triassic): an early independent experiment in gigantism.
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Thyreophora includes various subgroups, including the suborders Ankylosauria and Stegosauria. In both the suborders, the forelimbs were much shorter than the hindlimbs, particularly in stegosaurs. The clade has been defined as the group consisting of all species more closely related to Ankylosaurus than to Triceratops. Thyreophora is the sister group of Cerapoda within Genasauria.
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No bones of either the front or hind limbs were preserved in the holotype of Acherontiscus. In addition, bones of the endochondral shoulder girdle (i.e. the scapulae and coracoids) are also missing. However, a well-developed dermal shoulder girdle (consisting of clavicles and an interclavicle) is preserved, indicating that the ancestors of Acherontiscus possessed forelimbs.
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The lower surface of the neck is dark blackish-brown or brown, while the chest and forelegs are black or blackish- brown. The abdomen is light, yellowish-straw in colour. The groin is the same colour of the forelimbs. The base of the tail is light in colour, while the tip is dark brown.
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With a total length of ca. 30 cm (12 in), it is a relatively large species of spiny rat. It is white with a strongly contrasting glossy-black cap, back and band down towards its forelimbs. Its long fur is dense and coarse, but not spiny, as in some other members of its family.
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The plates on the neck are small and triangular. The head must have been relatively large with thirty teeth in each lower jaw. The hips are very broad and the low neural spines of the four sacral vertebrae and the first tail vertebra have been fused into a single plate. It also had robust forelimbs.
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A juvenile keeps its forelimbs pressed to the side of its carapace, and propels itself by kicking with its hind limbs. As the juvenile matures, its swimming method is progressively replaced with the adult's alternating-limb method. They depend entirely on this method of swimming by one year old. Water temperature affects the sea turtle's metabolic rate.
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Loggerheads crush prey with their large and powerful jaws. Projecting scale points on the anterior margin of the forelimbs allow manipulation of the food. These points can be used as "pseudo-claws" to tear large pieces of food in the loggerhead's mouth. The loggerhead will turn its neck sideways to consume the torn food on the scale points.
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Have a prominent shield on dorsal surface of the head extending posterior toward but not touching the tympanum. Forelimbs each have five claws and the hind limbs have four claws. Gray tail which is shorter than half the carapace length. Hatchling have a (mean carapace length 26.7 ± 0.3 mm; mean carapace width 26.8 ± 0.6 mm, n = 16).
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Some orange vermiculations may occur on the head, and the lower jaw may be red. Other skin is gray to olive, and there is a fringe of large scales on the outer border of the forelimbs. Males have slightly longer, thicker tails with the vent nearer the tip, and a deep plastral notch. Females have a shallow plastral notch.
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The boodie is a small, rat-like marsupial with short, rounded ears and a lightly haired, thick tail. This animal has a pointed rostrum and beady black eyes, hind limbs longer than the forelimbs, and large hind feet. This bettong is yellow-gray above and light gray below. Its short, dense fur feels soft and woolly.
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Restoration The skeleton is preserved in dorsal view and largely complete, with the bones still articulated and impressions of some of the integument. But part of the pectoral girdle is missing and part is still encased in stone. In 1987, Gans et al. published a revised description: they found that the patagium did not extend to the forelimbs.
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The rest of the long bones of the limb have been lost. Allegedly, the radius was similar to but smaller and straighter than the tibia, and there was a hole present between the tibia and fibula. The 14 preserved phalanges, which likely include elements from both the forelimbs and the hindlimbs, are long and hourglass- shaped.
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An adult greater Egyptian jerboa has a head-and-body length of about and a tail of . The upper parts are yellowish-brown or sandy- brown and the underparts are white. The hind legs are very large and are about four times longer than the forelimbs. The feet have hairy pads which improves locomotion on sand.
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Unlike most members of the family Canidae, foxes have partially retractable claws. Fox vibrissae, or whiskers, are black. The whiskers on the muzzle, mystaciae vibrissae, average long, while the whiskers everywhere else on the head average to be shorter in length. Whiskers (carpal vibrissae) are also on the forelimbs and average long, pointing downward and backward.
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Photographs of a male museum specimen. The anomalures, including Z. insignis, are unique among rodents in having a set of scales on the ventral surface of the base of the tail. These scales reportedly provide traction when climbing trees. Z. insignis is the only anomalure that lacks patagia (membranes that span between the forelimbs and hindlimbs).
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African pygmy squirrels are the smallest squirrel species in the world. These pygmy squirrels have longer hind limbs than forelimbs, an arched profile skull, rooted cheek teeth, and ever growing incisors. The African pygmy squirrel's tiny body is more mouse-like than squirrel-like. The borders of the eyes and ears are rounded with white edges at the tip.
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The tail of C. goodwini shrew is short and it accounts for approximately 35% of their body length. The forelimbs of the shrew with its long claws distinguish this from other shrews. Relative to other shrews, their face is long and thin. Of all the species in the genus Crptotis, they show the greatest reduction in teeth.
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Chimaerasuchus is known from one specimen, a partial skeleton. It was not a particularly large animal, estimated to be around 1 metre long and not very heavily built. The skull would have been short but quite large compared to much of the rest of the body. Its forelimbs were short but had sharp and highly curved claws.
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The forelimbs of Acerosodontosaurus are among the most diagnostic parts of the body. The only preserved portion of the pectoral girdle is a thin, slightly curved bone with tapered tips. This is likely a cleithrum, a bone which is absent in practically all diapsids. The only other neodiapsid known with certainty to retain a cleithrum is Hovasaurus.
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Mount with Wonambi The animal was extremely robust with powerfully built jaws and very strong forelimbs. It possessed retractable claws, a unique trait among marsupials. This would have allowed the claws to remain sharp by protecting them from being worn down on hard surfaces. The claws were well-suited to securing prey and for climbing trees.
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The generic name, Nothronychus, is derived from Greek νωθρός (nothros, meaning slothful) and ὄνυξ (onyx, meaning claw). The specific name, mckinleyi, honours rancher Bobby McKinley on whose land the fossil findings were made. The holotype, specimen MSM P2106, consists of very sparse skull fragments, a braincase, some vertebrae and parts of the shoulder girdle, forelimbs, pelvis and hindlimbs.
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Comparing Didymictis to Vulpavus, a much smaller and more agile viverravid, noted that Didymictis' limbs, especially the hindlimb, are similar to those in extant carnivornas adapted for speed, and the forelimbs to some extent are specialized to digging. The authors concluded that Didymictis was a relatively specialized terrestrial carnivore capable of hunting with speed or pursuing by digging.
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The trunk is elongate, with thin ribs extending from each vertebra. The presence of a large scapulocoracoid in Hyloplesion distinguishes it from Microbrachis. The limb bones are small and robust, with the hindlimbs being quite larger than the forelimbs . Like other microbrachomorphs such as Microbrachis, Hyloplesion has only three digits in the manus, a condition known as tridactyly.
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Girdle bones and caudals were relatively tiny. The forelimbs were of equal length to the hindlimbs, indicating that newly hatched Massospondylus were quadrupedal, unlike the bipedal adults. The discovery of hatching footprints with manus impressions confirmed their quadrupedality. These impressions show that the hand was not pronated, with palm faces facing each other and the thumb facing forwards.
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Marine mammals have evolved several times, developing similar flippers. The forelimbs of cetaceans, pinnipeds, and sirenians presents a classic example of convergent evolution. There is widespread convergence at the gene level. Distinct substitutions in common genes created various aquatic adaptations, most of which constitute parallel evolution because the substitutions in question are not unique to those animals.
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Metriorhynchids are fully aquatic crocodyliforms. Their forelimbs were small and paddle-like, and unlike living crocodilians, they lost their osteoderms ("armour scutes"). Their body shape maximised hydrodynamy (swimming efficiency), as they did have a shark-like tail fluke. Metriorhynchids were the only group of archosaurs to become fully adapted to the marine realm, becoming pelagic in lifestyle.
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In mice, however, both hindlimbs and forelimbs can develop in the presence of either Tbx4 or Tbx5. In fact, it is the Pitx1 and Pitx2 genes that appears to be necessary for specification of the developing hindlimb, whereas their absence results in forelimb development.Tbx4 and Tbx5 appear to be important specifically for limb outgrowth in mice.
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Other remains attributed to Batrachotomus have been collected in Vellberg-Eschenau, about 10 km east of Schwäbisch Hall, and in Crailsheim. The most notable are from Vellberg-Eschenau, which are represented by well preserved ribs and vertebrae (MHI 1895), and evidence of forelimbs and hindlimbs (SMNS 90018). Batrachotomus today is displayed in the Muschelkalk Museum, Ingelfingen, Stuttgart.
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Today, the mummy is considered one of the most important fossils of the AMNH. The mummy was discovered lying on its back, its neck twisted backwards and its forelimbs outstretched. The skeleton is complete save the tail, hind feet, and the hind portion of the pelvis. All bones are preserved unflattened and still connected to each other.
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Adult males in the type series measure and adult females in snout–vent length. The snout is rounded in dorsal view and truncate in profile. The supratympanic fold is well developed and covers the upper edge of the tympanum. The forelimbs are moderately robust; the fingers are moderately long, have large discs, and are about one-third webbed.
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Its carapace is studded with long, sharp spikes. Anguirus' tail is covered with spikes (it also had a tail club in Godzilla: Final Wars). Its tail makes up most of its body length. Its hind limbs are longer than its forelimbs, and it can stand up on them to its full height, though it generally walks upon all fours.
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The hind limbs are short and the toes have basal webbing. All dorsal surfaces have small tubercles, and there are large tubercles on head and body. The dorsum is brown and may have an orange- brown middorsal stripe posteriorly. The limbs are orange-brown; forelimbs have dark brown markings and hind limbs have dark brown to black bars.
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Despite its name, the finless porpoise has two fins, and several species of legless lizards have tiny useless legs, such as pygopodids which retain rudimentary flaps. Contrarily, the worm lizard Bipes as its scientific name suggests has two stubby forelimbs which actually assist in digging similar to a mole. All other amphisbaenians have reduced or absent forelimb girdles.
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Unlike most theropods, the front teeth of M. knopfleri projected forward instead of straight down. This unique dentition suggests that they had a specialized diet, perhaps including fish and other small prey. Other bones of the skeleton indicate that Masiakasaurus were bipedal, with much shorter forelimbs than hindlimbs. M. knopfleri reached an estimated adult body length of around .
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Journal of Systematic Palaeontology, 6, pp 1-40 doi:10.1017/S1477201907002271 Heterodontosaurids are very small (body length < 1 m) and lived from the Late Triassic to Early Cretaceous. Apart from Abrictosaurus all have a short upper canine and longer lower canine. The forelimbs in known fossils are relatively long. The major clades were already established by the early Jurassic.
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These frogs, though much smaller than their Western counterparts, are used by Chinese to cook frog legs and by Filipinos who cook them using the adobo method. The frog's forelimbs and hind legs are fried in oil, while in the adobo method (in which the entire frog is utilized), they are cooked in soy sauce and vinegar.
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49, 69 Hand of the holotype, with the first finger restored on the right The forelimbs of Ornitholestes were relatively long, slightly under two-thirds the length of the hind legs.Ostrom (1969), p. 146; Paul (2002), p. 236 The humerus (upper arm bone) was heavily built, and somewhat longer than the radius and ulna (forearm bones).
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The animal's broad sternal bones also demonstrate a wide pectoral girdle, giving it a broad-shouldered, broad-chested appearance. Paleontologist Kenneth Lacovara compared the animal's gait to an Imperial Walker. Although the forelimbs of D. schrani are longer than in any other previously known titanosaur, they are not significantly longer than the hind limbs. Therefore, Lacovara et al.
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The northern mole vole is a small mammal about long with a short tail, weighing up to 70 g. The females are slightly larger than the males. The body is wedge-shaped, the head flat, the neck short and the musculature of the forelimbs strongly developed. It has short, dense, brownish fur somewhat paler on the underparts.
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The plastron is orange-red, and may also have large dark blotches. The limbs and head are olive dorsally with the forelimbs lighter and the hind-limbs orange-red ventrally. There are dark flecks on the head and dark lines that radiate from the eyes. The throat is mottled and there may be small, dark bars on the lips.
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Carnufex possesses a myriad of features characteristic of both crocodylomorphs and their more distant ancestors, reptiles like Postosuchus. However, it is also highly autapomorphic, meaning that it possessed many other features which are completely unique to it, distinguishing it from its close relatives. The skull was large, elongated, and heavily textured in some areas, while the forelimbs were small.
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There are a few theories for the reasons feathers evolved in the first place, if not for flight. The first is that they served a purpose as insulation. Theropods have been found covering their nests with their forelimbs, thought to be sheltering their young. Feathers known to be found on theropods would have played an important role for insulation.
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The genus was proposed by William Ogilby in a presentation to the Linnean Society of London of a new species tentatively assigned to a genus of bandicoots, the long-nosed Perameles, and being forwarded to John Gould, then at Sydney, for a more detailed examination. Ogilby submitted a drawing by the collector Major Mitchell, who also supplied extensive remarks on the form and habits of the animal, and identified the unusual pig-like toes of the forelimbs as the basis for a new genus. The collection of the specimen was made at the interior of New South Wales by Mitchell, on the banks of the Murray River. The genus name Chaeropus combines terms derived from Ancient Greek for pig and foot, a reference to the unique characteristic of the forelimbs noted by the describing author.
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Diagram of Deinonychus (left) and Archaeopteryx (right) forelimbs illustrating wing-like posture Contrary to the way theropods have often been reconstructed in art and the popular media, the range of motion of theropod forelimbs was severely limited, especially compared with the forelimb dexterity of humans and other primates. Most notably, theropods and other bipedal saurischian dinosaurs (including the bipedal prosauropods) could not pronate their hands—that is, they could not rotate the forearm so that the palms faced the ground or backwards towards the legs. In humans, pronation is achieved by motion of the radius relative to the ulna (the two bones of the forearm). In saurischian dinosaurs, however, the end of the radius near the elbow was actually locked into a groove of the ulna, preventing any movement.
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Its cervical ribs - which are long, like that of the adult - face the same direction as the dorsal vertebrae of the adult, which is in contradiction to the typical head-first method of swallowing prey among amniotes. It is also preserved with its neck curling towards its forelimbs, a posture which is seen among vertebrate embryos but not adult Dinocephalosaurus specimens, which generally have the neck bent upwards. The absence of hands associated with the forelimbs in the embryo may be an artifact of preservation, but it may also be due to the sequence in which the limb bones of tetrapods ossify. Although the presence of an embryo per se would be equivocal regarding this issue, the conditions in which the embryo were preserved provide strong evidence that Dinocephalosaurus was viviparous.
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Victoriapithecus macinnesi had a dental formula of 2:1:2:3 on both the upper and lower jaws. Its lower molars are bilophodont with low cusps. The canines show sexual dimorphism and the mandible is relatively deep compared to other Old World monkeys. On the forelimbs, the distal end of the humerus shows a narrow articulation and a deep ulnar notch.
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A resting loggerhead sea turtle Loggerhead sea turtles observed in captivity and in the wild are most active during the day. In captivity, the loggerheads' daily activities are divided between swimming and resting on the bottom. While resting, they spread their forelimbs to about midstroke swimming position. They remain motionless with eyes open or half-shut and are easily alerted during this state.
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Lourinhasaurus alenquerensis is a herbivorous dinosaur measuring an estimated seventeen meters (56 feet) in length. It is characterized by the morphology of its first seven dorsal vertebrae with relatively high, bifurcated neural apophyses; also, the posterior cervical vertebrae have prominent ventral longitudinal keels on their centra. It is thought that it may have resembled Camarasaurus, albeit with proportionately longer forelimbs.
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Although the limb bones of terrestrial animals strengthen during development, semiaquatic animals have less need for such strengthening, and as a lineage becomes more inclined to an aquatic lifestyle, the limbs become less inclined to fully ossify as they develop. Vadasaurus's not-fully- fused forelimbs are an intermediate form between the strong limbs of terrestrial rhynchocephalians and the weaker limbs of pleurosaurids.
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420 pp. New Haven: Yale University Press both adherents of the "thecodont" hypothesis about the origins of birds. These "proaves" were supposed to be arboreal, with short necks, long trunks, sprawling legs, non-elongated hindlimbs, small hands and feet, small general size, and gliding on membranes. Feduccia's "protoavis" had membranes on the forelimbs only and was fashioned on the model of Megalancosaurus.
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The feed intakes of adult chinchillas are about 5-6% of their weights. The posture of the chinchilla when eating food is like that of the squirrel. They use hind limbs to sit and use forelimbs to grab the food and put them in their mouth. Chinchillas require a dust bath at least twice a week in fine volcanic ash.
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Therefore, the modification of the forelimbs in the evolution of abelisaurids seems to have occurred in a modular fashion, starting with the distal elements such as the fingers, and only later affecting the more proximal elements. It is with this evidence that Eoabelisaurus confirms a recently proposed evolutionary scenario of abelisaurid limbs based on the incomplete evidence of Cretaceous abelisauroids.
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The species has also been found in the formations in and around Badlands National Park. The ancient tortoises had primitive jaw muscles, unlike today's tortoises, which also display the os transiliens bone, and would have been herbivorous. While Stylemys species did exhibit the same neck structure as modern tortoises, the forelimbs were unsuitable for burrowing, setting them apart from modern genera.
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A. skrbinensis was a small marine squamate with 30 dorsal vertebrae. Unlike A. suessi, A. skrbinesis had forelimbs which were much more reduced than the hindlimbs. It had a humerus/femur ratio of 0.40, compared to 0.61 in A. suessi and 0.62 in A. microbrachis. In its gastric contents, there was phosphatic matter which was probably the remains of small fishes.
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The pubic bones of birds and some bipedal dinosaurs are turned backward. Scientists associate this with a shift in the center of gravity of the body backward. The reason for this shift is called the transition to bipedality or the development of powerful forelimbs, as in Archeopteryx.Kurochkin E. N. Synopsis of Mesozoic Birds and Early evolution of Class Aves // Archaeopteryx.
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Larvae hatch after two to five weeks, depending on temperature. As in all salamanders and newts, forelimbs develop first, followed later by the back legs. Unlike smaller newts, crested newt larvae are mostly nektonic, swimming freely in the water column. Just before the transition to land, the larvae resorb their external gills; they can at this stage reach a size of .
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Biostratigraphy of the Beaufort Group (Karoo Supergroup). South African Committee for Stratigraphy Biostratigraphic Series, 1: 1–46. ed. Gondwana and Laurasia during the Triassic Angonisaurus was named by its discoverers Cox and Li in 1983. In the name Angonisaurus, "an" means without, and "gon" means angle(d) or knee, which refers to the erect hind limbs with forelimbs that bend at the elbow.
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It possesses vomerine teeth with two slightly oblique oval groups just behind the level of the rear edge of the choanae. The males of the species lack vocal sacs. The first fingers of the forelimbs extend slightly beyond the second. At the ventral surface of each joint are well-developed tubercles and there is a single oval tubercle along the inner metatarsals.
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The immobilised prey is transported in the mandibles held against the underside of the body with the forelimbs. As many as 30 beetle larvae have been recorded in a single cell. The egg is laid before the prey is collected and is suspended from the side of the cell by a fine filament. The egg hatches a few days after it is laid.
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The elbow is a hinge joint without rotary movements and the forelimbs are relatively short. The humeri of Zygorhiza and Chrysocetus are more gracile than those of Dorudon. The vertebral formula is 7 cervicals, 15 thoracics, probably 13 lumbars, 2 sacrals, and at least 21 caudals. The centra of the posterior thoracic, lumbar, sacral, and anterior caudal are slightly elongated.
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Its skull was large and equipped with dozens of sharp, serrated teeth. It averaged in length, though fragmentary remains suggest it could have reached over . Relative to the large and powerful hindlimbs, its three-fingered forelimbs were small, and the body was balanced by a long and heavily muscled tail. It is classified as an allosaurid, a type of carnosaurian theropod dinosaur.
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Comparison of A. ajax (orange) and A.louisae (red) with a human (blue) and Brontosaurus parvus (green) Apatosaurus was a large, long-necked, quadrupedal animal with a long, whip-like tail. Its forelimbs were slightly shorter than its hindlimbs. Most size estimates are based on specimen CM3018, the type specimen of A.louisae. In 1936 this was measured to be , by measuring the vertebral column.
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Qianosuchus' scapulae were thin and short, but had an extremely broad dorsal blade. Its coracoid bones were oval-shaped and quite thin, while its clavicles articulated almost at right angles with the interclavicle to form an L-shaped outline from the side. The humeri were slender and lightly built, and almost totally straight. Neither partial skeleton has preserved the forelimbs below the elbows.
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The snout-to-vent length of the polkadot poison frog is . The hind limbs are short and the forelimbs relatively long with large hands. The fingers are unwebbed, the second one being longer than the first, and all but the first finger have flat discs of thickened skin. This frog has brown eyes and no teeth in its upper jaw.
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The fingers are flattened and have expanded discs at their tips. There is no webbing between the digits of either hands or feet. The head and back of this frog is orange-red, sometimes with black spots or mottling, especially towards the rear. The hind limbs are largely black and the forelimbs and underparts vary in colour, sometimes being black and sometimes orange.
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Journal of Evolutionary Biology, 14, 6, 987-991 This compression is represented in the aspect ratio of Muraenosaur limbs. The aspect ratio of the hind limbs is much greater than that of the fore limbs, representing a longer and more slender form. The high aspect ratio in the forelimbs may have been used for increasing maneuverability at some cost to the animal's endurance.
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Female Male, the holotype Anolis podocarpus is a medium-sized lizard with a snout-to-vent length of up to and a slender tail more than twice as long. Females are usually slightly smaller than males. The forelimbs are short and the hind limbs about twice as long. There are five digits on the forefeet and four long digits on the hind feet.
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Forelimbs are reddish brown in color with black cross bands. The lateral aspect of the body is greyish black with the color fading towards the groin. Anterior portion of the thigh has a black band terminating just short of the groin. In life, the frog is primarily brown in color with contrasting black markings on dorsum, hands, feet and flanks.
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Symptoms in cats include lesions on the face, neck, forelimbs, and paws, and, less commonly, upper respiratory tract infections. Symptoms of infection with cowpox virus in humans are localized, pustular lesions generally found on the hands and limited to the site of introduction. The incubation period is 9 to 10 days. The virus is most prevalent in late summer and autumn.
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Symptoms in cats include lesions on the face, neck, forelimbs, and paws, and less commonly upper respiratory tract infections. Symptoms of infection with cowpox virus in humans are localized, pustular lesions generally found on the hands and limited to the site of introduction. The incubation period is 9 to 10 days. The virus is prevalent in late summer and autumn.
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Berman et al. (2000) supported this hypothesis, as the Tambach Formation preserved Seymouria fossils while also completely lacking aquatic animals. They also pointed out the well-developed wrist and ankle bones of the "Tambach lovers" as supportive of terrestrial affinities. Despite the strong musculature of the forelimbs, Romer (1928) and White (1939) found little evidence for burrowing adaptations in Seymouria.
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In contrast, dorudontines had a shorter but powerful vertebral column. They too had a fluke and, unlike basilosaurids, they probably swam similarly to modern cetaceans, by using caudal oscillations. The forelimbs of basilosaurids were probably flipper-shaped, and the external hind limbs were tiny and were certainly not involved in locomotion. Their fingers, however, retained the mobile joints of their ambulocetid relatives.
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Aside from elongate hind limbs, Tianyuraptor is different from other members of Microraptorinae in regards to the relative lengths of the forelimb elements. The forelimbs of Tianyuraptor are proportionally much shorter than those of larger dromaeosaurids. For example, a similar-sized Velociraptor specimen shows an arm/leg length ratio of approximately 0.75., while Tianyuraptor has an arm/leg ratio of 0.53.
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Shuvuuia is a genus of bird-like theropod dinosaur from the late Cretaceous period of Mongolia. It is a member of the family Alvarezsauridae, small coelurosaurian dinosaurs which are characterized by short but powerful forelimbs specialized for digging. The type (and only known) species is Shuvuuia deserti, or "desert bird".Chiappe, L.M., Norell, M. A., and Clark, J. M. (1998).
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This has led researchers to suggest that it may have been the earliest known relative to the evolutionary line leading to Theria. The genus name, Fruitafossor, comes from Fruita, Colorado, where it was discovered. The "fossor" indicates the fossorial, or digging, specialization of the forelimbs. The specific epithet, windscheffeli, is in honor of Wally Windscheffel, who discovered the specimen along with C. Safris.
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Overall, Smilodon was more robustly built than any extant cat, with particularly well- developed forelimbs and exceptionally long upper canine teeth. Its jaw had a bigger gape than that of modern cats, and its upper canines were slender and fragile, being adapted for precision killing. S. gracilis was the smallest species at in weight. S. fatalis had a weight of and height of .
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Raorchestes beddomii from Günther, 1876 Raorchestes beddomii are small frogs: males grow to a snout-vent length of and females to . Their colouration is nearly uniformly green on dorsum, dorsal side of forelimbs, hindlimbs, and loreal and tympanic regions. Their iris is reddish brown. Size and colouration varies between the populations; frogs from Munnar were the larger and had lighter colour.
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Like many other lepospondyls, Utaherpeton is salamander-like in appearance. It has an elongated body made up of 26 presacral (neck and back) vertebrae. The total body length excluding the tail is about . The forelimbs are markedly smaller than the hind limbs and the hind feet are unusual in that they are larger than the rest of the hind limbs.
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The forelimbs of later forms are very robust, with a massive humerus and ulna. The wrist bones were reinforced by a fusion into two blocks, an ulnar and a radial. The front feet of stegosaurians are commonly depicted in art and in museum displays with fingers splayed out and slanted downward. However, in this position, most bones in the hand would be disarticulated.
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Anisodon grande, formerly Chalicotherium grande. Unlike modern perissodactyls, chalicotheres had clawed feet. They had longer forelimbs and shorter hind limbs, lower incisors that cropped food against a toothless pad in the upper jaw, low-crowned molar teeth, and were browsers on trees and shrubs throughout their history. They evolved in two different directions, which became separate subfamilies, the Schizotheriinae and the Chalicotheriinae.
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Studies of tooth wear suggest they ate leaves, twigs, fruit, and bark. Chalicotheriines, such as Anisodon, lived only in moist, closed-canopy forests, never reached the Americas, and developed very unusual anatomy for an ungulate. Their shorter necks and horse- like heads did not show adaptations to reach high. Instead, they developed very long forelimbs with mobile shoulder joints and hooklike claws.
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Adult hooded scaly- foots range from 45 to 55 cm long, with an average snout to vent length of 22.7 cm. Females are generally larger than males. Hooded scaly-foots show no trace of forelimbs, whilst the hind limbs are reduced to scaly flaps. These hind limbs are small and paddle-shaped, with modified scales which do not aid in movement.
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Twenty pairs of bony scutes ran down the midline of the back. The vertebrae lacked the procoelous articulation (concave anterior and convex posterior faces) of more derived crocodyliforms. Dakotasuchus had short broad shoulder blades, suggesting it had stout powerful forelimbs and perhaps terrestrial habits. M. G. Mehl, who described the genus, estimated the length of the type individual when complete to have been .
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Hziulquoigmnzhah (also Ziulquaz- Manzah) is the son of Cxaxukluth. He is also the brother to Ghisguth and the uncle of Tsathoggua. His appearance is much like his nephew, but he has an elongated neck, very long forelimbs, and very short, multiple legs. He has had many homes including Xoth (possibly Sirius B), Yaksh (Neptune), and Cykranosh (Saturn), where he resides to this day.
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Shoulder stability would decrease with the evolution of bipedalism. Shoulder mobility would increase because the need for a stable shoulder is only present in arboreal habitats. Shoulder mobility would support suspensory locomotion behaviors which are present in human bipedalism. The forelimbs are freed from weight-bearing requirements, which makes the shoulder a place of evidence for the evolution of bipedalism.
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Their examination of the specimen found the "Talkeetna Mountains Hadrosaur" to be a juvenile animal about 3 m (10 feet) long. It preserves the bones of the forelimbs, part of the front feet, ribs, and tail vertebrae. Other remains probably include the back vertebrae and pelvis. The researchers could not tell if the Talkeetna Mountains Hadrosaur was a hadrosaurid or lambeosaurid.
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Sexual dimorphism Keichousaurus hui was found in 1958 in Guizhou, China by palaeontologist Hu Chengzhi. This fossil is distinguished by its broad ulna which makes it unlike other European genera. The broad ulna increased the surface area of the forelimbs, making it more effective in locomotion. Keichousaurus shows many characteristics of its family Pachypleurosauridae such as its short snout and elongated temporal openings.
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In genera where both neck and forelimb elements are preserved, however, the necks were equal in length or longer than the forelimbs, so pulling vegetation would only be likely if lower parts of long branches were pulled down to access out-of-reach vegetation. Lautenschlager also found that therizinosaurid claws would not have been used for digging, which would have been done with the foot claws because, since as in other maniraptorans, feathers on the forelimbs would have interfered with this function. Additionally, this action leads to a higher stress tension on the dorsal area of the claw−this is more evident in Therizinosaurus. However, he could neither confirm nor disregard that the hand claws could have been fully used for sexual display, self-defense, intraspecific competition, mate- gripping during mating or grasping stabilization when foraging.
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A Vizla wearing a pet harness A pet harness is equipment consisting of straps of webbing that loop nearly around—that fasten together using side release buckles—the torso of an animal. These harnesses generally are made to have both a strap on the chest in front of the forelimbs, and a strap around the torso behind the forelimbs, with straps in between connecting these two. Having a D-ring suitable for (pet tags and) a leash to clip to, they are most often used to restrain an animal, but dogs also particularly wear them to assist a person with a disability or haul people and items. There is also the lifting harness for dogs with disabilities, covered in this article. Some come in different sizes, although many are size-adjustable with tri-glide slides to loosen or shorten the straps’ length.
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The hind limbs of Euparkeria are somewhat longer than its forelimbs, which has led many researchers to conclude that it could have occasionally walked on its hind legs as a facultative biped. Other possible adaptations to bipedalism in Euparkeria include rows of osteoderms that could have stabilized the back and a long tail that could act as a counterbalance to the rest of the body. Paleontologist Rosalie Ewer suggested in 1965 that Euparkeria may have spent most of its time on four legs but moved on its hind legs while running. However, adaptations to bipedalism in Euparkeria are not as obvious as they are in some other Triassic archosauriforms such as dinosaurs and poposauroids; the forelimbs are still relatively long and the head is so large that the tail may not have effectively counterbalanced its weight.
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Courtship is similar to other iguanids, with males approaching and tongue flicking the female's back, forelimbs and nuchal regions after a series of rapid head bobs. The breeding season occurs during the month of November. The Fiji banded iguana is oviparous and has a long incubation period of 160-170 days. Females guard the nest of three to six eggs, which is unusual for iguanids.
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This bettong exhibits a slow gait and fast gait. The fast gait (or bipedal hop) is characteristic of the macropodiforms and uses only the hind limbs, with the forelimbs held close to the body and tail acting as a counterbalance. The slow gait (or quadrupedal crawl) is used during foraging and other unstressed times. Nighttime movement is usually fairly limited, averaging less than 200 m.
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German zoologist and botanist Peter Simon Pallas originally described the alpine pika in 1773, in his work Reise durch verschiedene Provinzen des Russischen Reichs. It is a large species in the pika family, Ochotonidae, which consists of small mammals that have short ears, forelimbs very slightly longer than hindlimbs, and no external tail. There are four recognised subspecies: O. a. alpina (Pallas, 1773), O. a.
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The forelimbs are moderately robust; the P. mephistocephalus holotype has a quite robust humerus and ulna, however. The hand is completely known, which is exceptional for ankylosaurids. It has five digits, and the phalangeal formula is 2-3-3-3-2, meaning that the innermost finger of the forelimb has two bones, the next has three, etc. The metatarsals are closely appressed and held vertical.
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Their bodies are chestnut brown. The fronts of their faces and their tail tufts are black; the forelimbs and thigh are greyish or bluish-black. Their hindlimbs are brownish- yellow to yellow and their bellies are white. In the wild, tsessebe usually live a maximum of 15 years, but in some areas, their average lifespan is drastically decreased due to overhunting and the destruction of habitat.
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An illustration of the Confuciusornithid wing, showing the enlarged first digit and avian shape. Much of its anatomy resembles that of archaeopteryx, especially the pectoral girdle and forelimbs. It is better adapted for flight than archaeopteryx, due to the elimination of two thoracic vertebrae. The development of a pygostyle also shows better adaptation for flight, as this replaces the long tails present in earlier birds.
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A. suessi was a small marine squamate with an elongate neck and body. It had 10 cervical, 29 dorsal, and at least 65 caudal vertebrae. It had a unique feature called pachyostosis, an anatomical feature that thickened the periosteal bone by increasing the osteogenic activity of periosteum. Both its forelimbs and hindlimbs were reduced in size, which suggests that it lived in a marine environment.
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Serial homology is a special type of homology, defined by Owen as "representative or repetitive relation in the segments of the same organism."R:Webster 1913 in Webster’s Revised Unabridged Dictionary, G. & C. Merriam, 1913 Ernst Haeckel preferred the term "homotypy" for the same phenomenon. Classical examples of serial homologies are the development of forelimbs and hind limbs of tetrapods and the iterative structure of the vertebrae.
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The right humerus is very fragmented, only preserving the proximal end and although the distal expansion is missing, it has a notable reduced distal end. Anteriorly, it preserves a developed depression for muscular attachment. The preserved right femur is more gracile compared to other elements, indicating that the animal had stronger forelimbs. This is seen as a possible and potential autapomorphy for this species.
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The only problem was that Tyrannosaur arms were far too reduced. The Jijaki modified the genetic code of a sample of Nanotyrannus to bring back the five ancestral digits buried in their junk DNA. With more capable forelimbs and enough time, Nanotyrannus eventually evolved into the Quintaglios. Meanwhile, on the Jijaki homeworld, nuclear war broke out, wiping out all Jijaki except for those on the Space Arks.
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The males clasp the female from behind the forelimbs and shake, a behavior called amplexus. Males sometimes clasp other amphibian species during breeding and shake them as well. The male only grabs with the front limbs and never uses his hind limbs during the courtship dance as he rubs his chin side to side pressing down on the female's head. The female struggles but later becomes subdued.
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Sizes of Diplodocus carnegii (orange) and D. hallorum (green) compared with a human. Among the best-known sauropods, Diplodocus were very large, long-necked, quadrupedal animals, with long, whip-like tails. Their forelimbs were slightly shorter than their hind limbs, resulting in a largely horizontal posture. The skeletal structure of these long-necked, long- tailed animals supported by four sturdy legs have been compared with suspension bridges.
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Bloomington, IN: Indiana University Press. A bipedal stance might have been adopted by Brachiosaurus in exceptional situations, like male dominance fights. The downward mobility of the neck of Brachiosaurus would have allowed it to reach open water at the level of its feet, while standing upright. Modern giraffes spread their forelimbs to lower the mouth in a relatively horizontal position, to more easily gulp down the water.
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This pattern of retractor muscles points to an elephantine locomotion, consistent with columnar posture. Restoration of Euoplocephalus forelimbs demonstrate similarities to crocodilian forelimb musculature. The most well developed muscles in the pectoral region had more of a weight- bearing function than a rotational one. It has also been postulated that the carpals and metacarpals bear resemblance to those of tetrapods with fossorial (burrowing) habits.
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Bonnan, Matthew F. and Adam M. Yates, "A new description of the forelimbs of the basal sauropodomorph Melanorosaurus: implications for the evolution of pronation, manus shape and quadrupedalism in sauropod dinosaurs". In Barrett & Batten (eds.), Evolution and Palaeobiology (2007), pp. 157–168. Yates (2007) placed Antetonitrus, Melanorosaurus, and Blikanasaurus as basal sauropods and declined to use the term Prosauropoda, as he considered it synonymous with Plateosauridae.
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The limbs are unusually long for tree squirrels. In the forelimbs, the humerus and radius are of equal length, an adaptation thought to increase the squirrel's ability to climb large trees, compensating for a lack of shoulder mobility. The longer hindlimbs allow for stronger muscles, so that the squirrel can leap over larger gaps, relative to its size, than more typically sized squirrels can.
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Measuring up to in length when full grown, the White Cay iguana is the smallest species of Cyclura. The back of adults is usually a gray-brown to orange-brown color. The dorsal scales, forelimbs, and portions of the head and face are highlighted in bright orange. Immature iguanas lack these bright colors, being either solid brown or grey with faint slightly darker stripes.
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Its upward-facing position indicates that the animal probably fell into mud and sank. Next year in 2008, a nearly complete skeleton came from the Chukochya River. That same year, locals near the Amga discovered mummified rhinoceros remains, and over the next two years, pelvic bones, tail vertebrae and ribs were excavated along with forelimbs and hind limbs with toes intact.Lazarev, P.A., Grigoriev, S.E., Plotnikov, V.V., 2010.
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The ischia were enlarged and contacted each other extensively, and the rear expansion of the blade of the ilium was long. Both Eichstaettisaurus species had stout hindlimbs similar in length to the forelimbs. The femur had a straight shaft, unlike most other lizards where it is sigmoidal. In the foot, the first metatarsal bone was slightly shorter than the second to fourth metatarsal bones.
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This is more similar to carcharodontosaurids than to Allosaurus. Life restoration Aside from its vertebrae, Acrocanthosaurus had a typical allosauroid skeleton. Acrocanthosaurus was bipedal, with a long, heavy tail counterbalancing the head and body, maintaining its center of gravity over its hips. Its forelimbs were relatively shorter and more robust than those of Allosaurus but were otherwise similar: each hand bore three clawed digits.
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Furthermore, thighbone specimen OUM J13561 has a length of about eighty-six centimetres.Hip, femur and sacrum In general, Megalosaurus had the typical build of a large theropod. It was bipedal, the horizontal torso being balanced by a long horizontal tail. The hindlimbs were long and strong with three forward-facing weight-bearing toes, the forelimbs relatively short but exceptionally robust and probably carrying three digits.
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Its forelimbs are only half the length of its hindlimbs, suggesting that it was bipedal. All of its long bones have hollow shafts. Eoraptor had five digits on each 'hand', the three longest of which ended in large claws and were presumably used to handle prey. Scientists have surmised that the fourth and fifth digits were too tiny to be of any use in hunting.
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A new pseudosuchian from the Orange Free State. Annals of the Transvaal Museum 5(1):83-87 [M. Carrano/M. Carrano/M. Carrano] on the basis of a mold of a mostly complete skeleton found in a quarry near Rosendal, Free State. The mold preserves most of the right half of the skeleton including the skull, ribs, dorsal vertebrae, forelimbs and hindlimbs, but not the tail.
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The sternum is represented by what is probably the left sternal plate. Five left sternal ribs are preserved, more than are seen in the related genera Microraptor and Sinornithosaurus. The furcula is preserved as well, as are the scapulae and coracoids, which are fused. The forelimbs of Zhongjianosaurus are represented by both humeri, the left ulna, the left radius, and a partial left manus.
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Sloths in this genus had a long, robust body with more than 19 thoracic vertebrae, a short skull, and long limbs with large, curved claws. They were small sloths, measuring about in length. On the ground, they probably walked on the knuckles of the forelimbs, like a gorilla. Hapalops had very few teeth with no incisors; the mandible included only four pairs of teeth.
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The throat has a large black blotch, extending to the base of the forelimbs. Males have a crest of spined scales running down the length of the body, which are longer than those of females. Males also have proportionally longer hind legs. Females are largely unmarked or have light speckles, and lack the dark crossbars of males, although may have dark banding on tail, especially young females.
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Cheloniidae is a family of typically large marine turtles that are characterised by their common traits such as, having a flat streamlined wide and rounded shell and almost paddle-like flippers for their forelimbs. The six species that make up this family are: the green sea turtle, loggerhead sea turtle, olive ridley sea turtle, hawksbill sea turtle, flatback sea turtle and the Kemp's ridley sea turtle.
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On the origin of the tetrapod limb. Acta Zoologica 14, 185–295. (2) Antecedents were present in the fins of early sarcopterygian fish. However, 2008 research which created a three-dimensional reconstruction of a Panderichthys, a coastal fish from the Devonian period 385 million years ago, shows that these animals already had many of the homologous bones present in the forelimbs of limbed vertebrates.
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The fossils of both groups are found in environments that had trees and shrubs. While chalicotheriines developed very derived body forms, schizotheriines remained basically similar in shape to other perissodactyls such as horses and tapirs. Like most forest-dwelling ungulates, they had long necks and forelimbs longer than their hindlimbs. Schizotheriines had longer, higher-crowned cheek teeth than chalicotheriines, which indicates they typically fed on tougher vegetation.
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Spinal cord segment The central pattern generators responsible for locomotion in vertebrates reside as half-center modules in the cervical and lumbar region of the spinal cord. Each CPG generates a basic motor output pattern that is responsible for the rhythmic contractions of flexor-extensor muscles that correspond to the forelimbs and hindlimbs.Marder E, Calabrese RL. Principles of rhythmic motor pattern generation. Physiol Rev. 1996;76:687–717.
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The forelimbs were smaller than the hindlimbs. The hand bore two large, clawed digits and a third, smaller digit that may have been non-functional. Their delicate skulls were narrow and long, with tapered snouts. The skull had five pairs of fenestrae (skull openings), the largest of which was for the orbit (eye socket), with the eyes being larger in proportion to the rest of the skull.
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The skull is lightly built with long and slender jaws and minute teeth. Shuvuuia is unique among non-avian theropods in the skull's ability to perform prokinesis, that is, it could flex its upper jaw independently of its braincase. The hindlimbs of Shuvuuia were long, slender, and short-toed, which may indicate significant running capabilities. The forelimbs, however, were unusually short and powerfully constructed.
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Throughout the rest of the century, paleontologists would be occupied with several controversies regarding ceratopsian paleobiology. One concerned the stance of the ceratopsid forelimbs. When Marsh first reconstructed the ceratopsid forelimb, he portrayed it in an erect posture. However, when later researchers like Sternberg and Osborn tried to mount the skeletons, they found that the forelimb bones apparently sprawled despite the hindlimbs standing straight up and down.
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It includes the forelimbs, hind limbs, hips, ribs, dorsal vertebrae, and much of the tail. Another specimen of Poposaurus from Arizona, PEFO 34865, includes not only postcranial remains but also cranial remains, confirming that Poposaurus was a hyper-carnivorous predator.Parker WG and Nesbitt 2013. Cranial remains of Poposaurus gracilis (Pseudosuchia: Poposauroidea) from the Upper Triassic, the distribution of the taxon, and its implications for poposauroid evolution.
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Amphisbaenia (called amphisbaenians or worm lizards) is a group of usually legless squamates, comprising over 180 extant species. Amphisbaenians are characterized by their long bodies, the reduction or loss of the limbs, and rudimentary eyes. As many species have a pink body and scales arranged in rings, they have a superficial resemblance to earthworms. While the genus Bipes retains forelimbs, all other genera are limbless.
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Roosting is a vertical upside down behaviour seen in bats which involves the use of the feet to grasp a surface. The hind limbs are very important as they provide most of the strength to support the bat. The forelimbs can be used as well, having all four limbs supporting the animal. The head and neck are usually kept at a 90o or 180o angle.
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Though giant mouse lemurs are relatively small cheirogaleids, they are more than three times larger than the smallest members of the family, the mouse lemurs. Their body weight averages . At around , their bushy and long tail is longer than their head-body length, which averages . Their forelimbs are shorter than the hind limbs (with an intermembral index of 70), a trait shared with mouse lemurs.
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Ateles hybridus from Venezuela Brown spider monkeys have long and thin limbs with their forelimbs being longer than their hind limbs. They also have a distinctive long flexible, thin and prehensile tail which at times acts like a fifth limb. The tail has a highly flexible, hairless tip with skin grooves which improves grip. Their hands look slightly curvy and they have small thumbs.
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The Bazna, also known as the Basner, Porcul de Banat, or Romanian Saddleback, is a breed of domestic pig native to Romania. The breed was first created in 1872 from crosses between the Mangalitsa and Berkshire pig breeds. The Bazna is primarily black with a white ring circling its trunk, starting at the shoulders and including the forelimbs. The breed was officially recognized in 1958.
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Another symptom of this syndrome is bone abnormalities in the fingers, wrists, or arms. An additional defect that Holt- Oram syndrome can cause is a conduction disease leading to abnormal heart rates and arrhythmias. Amelia syndrome is a condition where forelimb malformation occurs because FGF-10 is not triggered due to Tbx5 mutations. This condition can lead to the absence of one or both forelimbs.
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The forelimbs had only two clawed fingers, along with an additional splint-like small third metacarpal representing the remnant of a third digit. The pelvis was a large structure. Its upper bone, the ilium, was both very long and high, providing an extensive attachment area for hindlimb muscles. The front pubic bone ended in an enormous pubic boot, longer than the entire shaft of the element.
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Only much later Janensch realised that two skeletons had been present. Skelett SI was represented by a skull, six neck vertebrae and some back vertebrae. Skelett SII was larger but despite its size still a subadult individual. It included skull bones, a series of eleven neck and eleven back vertebrae, ribs, the left scapula, both coracoids, both forelimbs, the pubic bones and the right hindlimb.
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Nanchangosaurus resembled a cross between an ichthyosaur and a crocodilian. It had a fusiform body, similar to a dolphin or an ichthyosaur, paddle-like limbs, with forelimbs being larger than hindlimbs, and a crocodilian-like tail for swimming through the water. It had bony scutes on its back, like an alligator, but had a long snout filled with teeth, like an ichthyosaur or a river dolphin.
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Black-handed tamarins are among the smallest primates, weighing approximately 500 grams. As with other tamarins, the hind limbs are longer than the forelimbs and the thumbs are not opposable. With the exception of the big toe, there are claws on all fingers and toes, as well as two molars on each side of the jaw. The face of the black tamarin is generally hairless.
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All this coloration, while helping to attract females, also has a downside: predators such as kestrels easily spot them. Females, on the other hand, have much more subdued coloration and are less likely to be eaten. The Augrabies flat lizard is very similar to Platysaurus capensis, or the Cape flat lizard, in scalation, but differs in having finer scalation on top of the forelimbs.
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All of the nesting specimens are situated on top of egg clutches, with their limbs spread symmetrically on each side of the nest, front limbs covering the nest perimeter. This brooding posture is found today only in birds and supports a behavioral link between birds and theropod dinosaurs. The nesting position of Citipati also supports the hypothesis that it and other oviraptorids had feathered forelimbs.
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Preaxial polydactyly occurs in SSTM 5025, where extra digits only develop anteriorly to digit I. This condition is seen in earlier stem tetrapods from the Devonian period, such as Ichthyostega and Acanthostega. SSTM 5025 possessed seven digits on the forelimbs and six on the hindlimbs. The wide manus and pes of the specimen resemble the limb-like fins of extant frogfishes.Clack, J. A. (2002).
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The eyes of zebras are at the sides and far up the head, which allows them to see above the tall grass while grazing. Their moderately long, erect ears are movable and can locate the source of a sound. Unlike horses, zebras and asses have chestnut callosities only on their front limbs. In contrast to other living equines, zebra forelimbs are longer than their back limbs.
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Many types of amplexus are identified in the literature. However, two types of amplexus are more common than others, known as inguinal and axillary amplexus. These two types of amplexus have been classified based on the position of the male amphibian relative to the female. When a male amphibian clasps a female around her waist (inguinal region) using his forelimbs, this is considered inguinal amplexus.
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The strong forelimbs are used to catch prey, to excavate dens, to dig out burrowing animals, to turn over rocks and logs to locate prey, and to club large creatures. Despite being quadrupeds, bears can stand and sit as humans do. Unlike most other land carnivorans, bears are plantigrade. They distribute their weight toward the hind feet, which makes them look lumbering when they walk.
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In contrast, the same two joints in Deinonychus allow up to 88 and 130 degrees of motion, respectively, while a human arm can rotate 360 degrees at the shoulder and move through 165 degrees at the elbow. The heavy build of the arm bones, strength of the muscles, and limited range of motion may indicate a system evolved to hold fast despite the stresses of a struggling prey animal. In the first detailed scientific description of Tyrannosaurus forelimbs, paleontologists Kenneth Carpenter and Matt Smith dismissed notions that the forelimbs were useless or that T. rex was an obligate scavenger. According to paleontologist Steven M. Stanley, the arms of T. rex were used for slashing prey, especially by using its claws to rapidly inflict long, deep gashes to its prey, although this concept is disputed by others believing the arms were used for grasping a sexual partner.
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Marley's golden mole has a compact, streamlined body, a wedge-shaped head, pointed muzzle and sleek, moisture repellent fur. The upper parts are a dark reddish-brown and the underparts range from dull brown to orange-brown. It has muscular shoulders with short powerful forelimbs and strong digging claws. The third claw is enlarged and there is no fifth digit and only a vestigial first and fourth digit.
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The tail probably ended in a long whiplash, much like Apatosaurus, Diplodocus and other diplodocids, some of which had up to 80 tail vertebrae. The limb bones of Barosaurus were virtually indistinguishable from those of Diplodocus. Both were quadrupedal, with columnar limbs adapted to support the enormous bulk of the animals. Barosaurus had proportionately longer forelimbs than other diplodocids, although they were still shorter than most other groups of sauropods.
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Barosaurus is a member of the sauropod family Diplodocidae, and sometimes placed with Diplodocus in the subfamily Diplodocinae. Diplodocids are characterized by long tails with over 70 vertebrae, shorter forelimbs than other sauropods, and numerous features of the skull. Diplodocines like Barosaurus and Diplodocus have slenderer builds and longer necks and tails than apatosaurines, the other subfamily of diplodocids. Below is a cladogram of Diplodocinae after Tschopp, Mateus, and Benson (2015).
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The tympanic region is light in colour, and has a dark supratympanic fold at the border. There are no distinct, dark crossbands on the forelimbs, however, on the hindlegs these bands are present. The cloacal region has a blackish colour, while the chest, ventral parts of the limbs, and throat are a dirty yellowish colour. The belly of this species has a similar colour, however it is more grayish.
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Gould,Stephen Jay (1993) "Bent Out of Shape" in Eight Little Piggies: Reflections in Natural History. Norton, 179–94. . Fins or flippers of varying forms and at varying locations (limbs, body, tail) have also evolved in a number of other tetrapod groups, including diving birds such as penguins (modified from wings), sea turtles (forelimbs modified into flippers), mosasaurs (limbs modified into flippers), and sea snakes (vertically expanded, flattened tail fin).
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Note below however, the observations on the malleus in the middle ear. The species range in size from about 8 to about 20 cm. They have muscular shoulders and the forelimbs are radically adapted for digging; all the toes on the forefeet have been reduced, except for a large, pick-like third claw on the third toe. The fifth digit is absent and the first and fourth digits are vestigial.
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It also provided details of the premaxilla, inner ear, and lower forelimbs, which were not preserved in any previous remains. The individual bones of CRILAR-Pv 552 were basically identical to their counterparts in Lewisuchus and Pseudolagosuchus specimens, providing irrefutable evidence that Pseudolagosuchus referred to the same species of reptile as Lewisuchus, and establishing Lewisuchus admixtus as the valid name for all fossils previously referenced with either name.
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Bats are mammals of the order Chiroptera. With their forelimbs adapted as wings, they are the only mammals capable of true and sustained flight. Bats are more manoeuvrable than birds, flying with their very long spread-out digits covered with a thin membrane or patagium. The smallest bat, and arguably the smallest extant mammal, is Kitti's hog-nosed bat, which is in length, across the wings and in mass.
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The loss of forelimbs and reduction of hind limbs in Eupodophis was likely an adaptation for swimming. While living snakes usually employ undulatory movement for moving over land, sinuous movements are also an effective means of moving through water. Large, well-developed limbs increase drag on swimming animals, so the limbs of Eupodophis and other early snakes may have become vestigial to save energy and make movement more efficient.
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Fossils now attributed to Tawa were first discovered in 2004. The holotype, a juvenile individual, cataloged GR 241, consists of a mostly complete but disarticulated skull, forelimbs, a partial vertebral column, hindlimbs, ribs, and gastralia. The determination was made that this specimen is a juvenile based on the presence of an open braincase and unfused neurocentral sutures. Fossils of at least seven other individuals were also discovered at the site.
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Tree-kangaroos have developed long tails for balancing in the trees, and strong forelimbs for climbing. Their teeth are developed for tearing leaves rather than cutting grass. The Buergers' tree- kangaroo, along with nine other species of tree-kangaroo, are endangered and on the brink of extinction. The key threats to their survival include dwindling habitat due to logging; mining; road kill by humans and predation by domestic and wild dogs.
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However, this model does not account for the fact that lizards may adjust their movements using their forelimbs and tail to increase the range of acceleration in which bipedal locomotion is possible.A dragon lizard that is capable of facultative bipedalism. Debate exists over whether bipedalism in lizards confers any advantage. Advantages could include faster speeds to evade predators, or less energy consumption, and could explain why this behavior has evolved.
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This feature is also found in some Lycaenidae (and also the Monotrysia), but in these the legs are always much longer. The sensory hairs on the tarsi of the female forelimbs are arranged in a group. These groups which are arranged in pairs can be found in the other taxa of the Papilionoidea. The third problematic apomorphy is the absence of the rear projections (apophyses) of the female genitalia.
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Restoration Puijila darwini was a semi-aquatic carnivore which represents a morphological link in early pinniped evolution. Its fossil remains demonstrate the presence of enlarged, probably webbed feet, robust forelimbs and an unspecialized tail. This suggests that Puijila swam quadrupedally using its webbed fore and hind feet for propulsion. Phylogenetic studies including molecular evidence suggest a sister relationship between pinnipeds (seals) and ursoids (bears) as well as musteloids (weasels and otters).
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The forelimbs, on the other hand, were used for movement due to the rotation of; the humerus, however, the femur was not able to rotate. Another unique feature of Hyperodapedon was the large eyes with sclerotic plates, which allowed for good sense of vision. They had large nasal capsules to sense smell. Since Hyperodapedon lacked a tympanum, it was believed that they could sense sound by the skin near the quadrate.
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Males may also develop a color of salmon to bright rusty-red over the entire undersides of the body and limbs. This new coloring may continue indefinitely in males. Male and female blunt-nosed leopard lizards exhibit several different physical behaviors. The simple headbob is a single, vertical motion of only the head whereas the pushup involves an up and down movement of the forelimbs and a headbob.
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Carnotaurus was a highly specialized theropod, as seen especially in characteristics of the skull, the vertebrae and the forelimbs. The pelvis and hindlimbs, on the other hand, remained relatively conservative, resembling those of the more basal Ceratosaurus. Both the pelvis and hindlimb bones were long and slender. The left thigh bone of the individual measures 103 cm in length, but shows an average diameter of only 11 cm.
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Foot of E. gouldi, with enlargements showing breakage of claws Eichstaettisaurus had a well-developed acromion process, or the attachment for the clavicle, on the scapula (shoulder blade). The clavicles of E. schroederi did not curve forward, unlike most members of the Autarchoglossa, and also lacked rearward projections. As in Ardeosaurus, both species of Eichstaettisaurus had relatively stout forelimbs. In E. schroederi, the olecranon process of the ulna was well-developed.
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A fossil of a pregnant Dakosaurus female recovered from the Late Jurassic Plattenkalk, Bavaria, preserves the complete skeleton of a neonate with small, paddle-like forelimbs unsuited for walking on land, similar to those of adults, further supporting live birth in metriorhynchids.Spindler, Frederik. Live Birth in a Jurassic Marine Crocodile [abstract]. In: Abstracts of the 90th Annual Meeting of the Paläontologische Gesellschaft, Munich 2019; 2019 Sept 15–18; Munich.
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Rukwatita is a genus of titanosaur sauropod dinosaur from the Galula Formation in Tanzania. It lived around 100 million years ago, during the middle Cretaceous. The species, which shared features with another southern African species, Malawisaurus dixeyi, measured from the head to the tip of the tail, and had forelimbs that were estimated around long. Fossils were found embedded in a cliff face near Lake Rukwa in the Rukwa Valley.
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The claws make it easy to see how many toes are fused into each part of the foot. On the forelimbs, there are two toes on the outer (distal) side of each foot and three on the inside (medial). On the hind legs, the arrangement is reversed: two toes are fused medially and three distally. Their eyes are the most distinctive among the reptiles and function like a gun turret.
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Like other tree-kangaroos, Goodfellow's tree-kangaroo is quite different in appearance from terrestrial kangaroos. Unlike its land dwelling cousins, its legs are not disproportionately large compared to its forelimbs which are strong and end in hooked claws for grasping tree limbs, and it has a long tail for balance. All of these features help it with a predominantly arboreal existence. Goodfellow's tree-kangaroo has short, woolly fur,Melbourne Zoo (2006).
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Triodia hummocks in the Pilbara region of Western Australia. Pebble-mound mice are the only mammals to create mounds of small stones around their burrows. The mice carry the pebbles in their mouths in a radius of around the nest and move them into location with their forelimbs. Mounds may cover areas of up to and include up to of pebbles, concentrated near burrow entrances, above burrows, and against trees.
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Typically for a theropod, Albertosaurus was bipedal and balanced the heavy head and torso with a long tail. However, tyrannosaurid forelimbs were extremely small for their body size and retained only two digits. The hind limbs were long and ended in a four-toed foot. The first digit, called the hallux, was short and only the other three contacted the ground, with the third (middle) digit longer than the rest.
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The fossils discovered in 2007 represent an almost complete skeleton. There are four skulls, two are complete and the others are nearly complete. The holotype consists of lower jaw, partial right hyoid, cervical vertebrae (3–8), right and left forelimbs (missing most phalanges), nearly complete carapace, left scapula and coracoid, partial hyoplastron and hypoplastron. The two partial shells are badly preserved but are distinct from those of other marine turtles.
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Lutrine opossums are quadrupedal and extremely agile. Although they are primarily terrestrial they are also adept climbers and swimmers. Their long body, proportionally short limbs, and no undulation of the vertebral column disqualifies them from being categorized as a specialized semi-aquatic mammal. Although they cannot be classified as truly specialized mammals, they are still considered strong swimmers drawing power from the hind limbs as the forelimbs paddle.
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The well-preserved forelimbs are the most distinctive parts of A. simonsi. A broad scapula and a ball-and-socket shoulder joint is characteristic of cetaceans, but Ancalecetus lacks both. The interior surface of the narrow scapula is not broadly curved as in most cetaceans, but tightly curved. The roughened vertebral border suggests the presence of a cartilaginous extension that extends the surface of the scapula like in modern cetaceans.
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The largest family in this group is Plethodontidae, the lungless salamanders, which includes 60% of all salamander species. The family Salamandridae includes the true salamanders and the name "newt" is given to members of its subfamily Pleurodelinae. The third suborder, Sirenoidea, contains the four species of sirens, which are in a single family, Sirenidae. Members of this order are eel-like aquatic salamanders with much reduced forelimbs and no hind limbs.
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Albertosaurus shared a similar body appearance with all other tyrannosaurids. Typically for a theropod, Albertosaurus was bipedal and balanced the heavy head and torso with a long tail. However, tyrannosaurid forelimbs were extremely small for their body size and retained only two digits. The hind limbs were long and ended in a four-toed foot on which the first digit, called the hallux, was short and did not reach the ground.
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The golden bandicoot is quite rat-like in appearance due to its small body, hunched-over posture, and relatively long tail. The hind limbs are large and muscular compared to the short forelimbs. Each forefoot has three toes with flat claws, used for digging holes when hunting for prey. And, unlike most marsupials, the golden bandicoot has fused toes on its hind feet, forming a comb they use for grooming.
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For example, the flipper of a turtle or of a dolphin, the arm of a human, the foreleg of a horse, and the wings of both bats and birds are ultimately homologous, despite the large differences between them. Specific uses of the forelimbs may be analogous if they evolved from different sub-structures of the forelimb, such as the flippers of turtles and dolphins, and the wings of birds and bats.
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Ristella is a genus of skinks endemic to the Western Ghats of southwestern India. They are commonly known as cat skinks because of their retractile claws. This genus can be instantly identified by the presence of only four fingers in forelimbs in all the species (instead of the usual five). All the members look more or less similar and are drab dark brown to blackish in complexion with paler undersides.
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The upper parts are a dark golden-brown tinged with a slight iridescence and the underparts are a lighter brown with a golden sheen. It has a compact, streamlined body and a wedge- shaped head and pointed muzzle. It has muscular shoulders, short powerful forelimbs and strong digging claws. The third claw is enlarged and there is no fifth digit and only a vestigial first and fourth digit.
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Duty factors over 50% are considered a "walk", while those less than 50% are considered a run. Forelimb-hindlimb phase is the temporal relationship between the limb pairs. If the same-side forelimbs and hindlimbs initiate stance phase at the same time, the phase is 0 (or 100%). If the same-side forelimb contacts the ground half of the cycle later than the hindlimb, the phase is 50%.
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Cape Tortoises: Their identification and care. Cape Nature Conservation. It looks superficially similar to the larger greater padloper (Homopus femoralis) of the grasslands in the east. However, the Karoo Padloper can be distinguished by its uniform colouration, its having five toes on its front feet versus four toes on its back feet, the smaller scales on its forelimbs, and its nostrils which are level with or above its eyes.
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The lengthening of the glenoid corresponds with a flattening of the proximal end of the humerus, a feature common in the forelimbs of more advanced stem tetrapods. Although the pectoral limb bones and girdle were not strong enough to support the weight of Tinirau out of water, glenoid lengthening and other changes to the proximal forelimb were among the first steps in the transformation from pectoral fin to forelimb.
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Dolphin anatomy Cetacean bodies are generally similar to that of fish, which can be attributed to their lifestyle and the habitat conditions. Their body is well-adapted to their habitat, although they share essential characteristics with other higher mammals (Eutheria). They have a streamlined shape, and their forelimbs are flippers. Almost all have a dorsal fin on their backs that can take on many forms depending on the species.
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The gliding posture of the greater glider is unique among marsupials. The forelimbs are folded so that the wrists are tucked under the chin, giving the patagium a triangular outline when outstretched. The animal regularly glides between high trees, and is able to use its tail to assist in steering. They avoid travelling along the ground whenever possible, and are slow and clumsy if forced to do so.
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The scapula (shoulder blade) was long, the humerus ranged from , and the ulna from . The bones associated with the forelimbs were generally small in proportion to the bird. The pelvis was large and strongly built in proportion to the size of the bird, was long, wide at the front, and wide at the back. The femur ranged from in length, the tibia from , and the metatarsus was long.
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"A Chinese archaeopterygian, Protarchaeopteryx gen. nov." Geological Science and Technology (Di Zhi Ke Ji), 238: 38–41. Translated By Will Downs Bilby Research Center Northern Arizona University January, 2001 It has been suggested that it could have had an arboreal lifestyle, jumping from tree limbs and using its forelimbs for a form of parachuting.Currie, P.J. (2004), Feathered dragons: studies on the transition from dinosaurs to birds, Indiana University Press, p.
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Titanosaur necks were of average length for sauropods, and their tails were whip-like though not as long as in the diplodocids. While the pelvis was slimmer than some sauropods, the pectoral (chest) area was much wider, giving them a uniquely "wide-legged" stance. As a result, the fossilized trackways of titanosaurians are distinctly broader than other sauropods. Their forelimbs were also stocky, and often longer than their hind limbs.
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Azendohsaurus was a stocky mid-sized reptile estimated to be roughly long. It had a small, box-shaped head with a short snout on a long neck that was raised above the shoulders. The body was broad, with a barrel-shaped chest and shoulders much taller than the hips, together with an unusually short tail. Its posture was semi-sprawled, with sprawling hind limbs and slightly elevated forelimbs.
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The overall patterns of the forelimbs and hindlimbs are so similar ancestrally, and branch out in similar ways; that they are given shared names. Limbs are attached to the pectoral girdle or pelvic girdle. The one bony element of the upper limb is the stylopodium, the two bones of the lower limb are the zeugopodium. The distal portion of the limbs, that is, the hands or feet, are known as autopodia.
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The upper jaw is hooked and the skin on the sides of the neck and the chin are lighter in color. The lower jaw may also sometimes possess a pair of small yellow spots on the sides. The legs possess irregular enlarged transverse scales and are darker in color at the front. Four transverse scales are present on the forelimbs and more at the hind limbs (though absent at the heels).
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With its weight rested on the pelvis, it may have been free to move the hindlimbs. Getting back up again might have involved some stabilization from the diminutive forelimbs. The latter known as Newman's pushup theory has been debated. Nonetheless, Tyrannosaurus was probably able to get up if it fell, which only would have required placing the limbs below the center of gravity, with the tail as an effective counterbalance.
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Even for an anteater, the neck is especially thick compared to the back of the head, and a small hump is found at the back of the neck. The coat is mostly greyish, brown or black and salted with white. The forelimbs are white, with black bands around the wrists, while the hindlimbs are dark. Thick black bands with white outlines stretch from throat to shoulder, ending in triangular points.
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217 Scelidosaurus was quadrupedal, with the hindlimbs longer than the forelimbs. It may have reared up on its hind legs to browse on foliage from trees, but its arms were relatively long, indicating a mostly quadrupedal posture. A trackway from the Holy Cross Mountains of Poland shows a scelidosaur like animal walking in a bipedal manner, hinting that Scelidosaurus may have been more proficient at bipedalism than previously thought.
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Adult males have a bluish head and a greenish back. A darker area in the middle and the vestiges of the juvenile stripes and spots are also present. The forelimbs are yellow to orange, the throat is dark blue, and the belly is black in the front but becomes orange near the tail. Above the tail, it is a tan color, while below and on the sides, it is orange.
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Like chrysochlorids and epoicotheres, notoryctids use their forelimbs and enlarged central claws to dig in a parasagittal (i.e., up and down) plane, as opposed to the "lateral scratch" style of digging that characterizes talpid moles. Marsupial moles spend most of their time underground, coming to the surface only occasionally, probably mostly after rains. They are blind, their eyes having become reduced to vestigial lenses under the skin which lack a pupil.
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Pachyophis Cladogram Pachyophis is considered a hind-limbed snake despite presence of any indication of forelimbs or shoulder girdle due to its other shared general morphology. All Simoliophiidae display evident pachyostosis (increase in bone massiveness) and osteosclerosis (increase in inner bone compactness). Pachyophis evidently displays such in their vertebrae specifically. Other shared characteristics include a smaller head and distally straight ribs for a lateral compression of the trunk.
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Its dental formula is , for a total of 18 teeth. While most other bats have almost completely lost the ability to maneuver on land, vampire bats are an exception.video They can run using a unique, bounding gait in which the forelimbs are used instead of the hindlimbs to propel forward, as the wings are much more powerful than the legs. This ability likely evolved independently within the bat lineage.
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Petter's big-footed mouse (Macrotarsomys petteri), is a Madagascan rodent in the genus Macrotarsomys. With a head and body length of 150 mm (5.9 in) and body mass of 105 g (3.7 oz), It is the largest species of its genus. The upperparts are brown, darkest in the middle of the back, and the underparts are white to yellowish. The animal has long whiskers, short forelimbs, and long hindfeet.
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Life reconstruction of Cynognathus crateronotus Cynognathus was a heavily built animal, and measured around in snout-to-vent body length. It had a particularly large head, up to in length, with wide jaws and sharp teeth. Its hindlimbs were placed directly beneath the body, but the forelimbs sprawled outwards in a more reptilian fashion. This form of double (erect/sprawling) gait is also found in some primitive mammals alive today.
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Life restoration Albertonectes is known solely from the holotype TMP 2007.011.0001, a complete well preserved postcranial skeleton housed at the Royal Tyrrell Museum of Palaeontology in Drumheller, Alberta. Elements include all 132 vertebrae from the atlas-axis complex to fused tip of the tail vertebrae, complete pectoral and incomplete pelvic girdles, almost complete forelimbs and hindlimbs, disarticulated ribs, a gastralium, and at least 97 associated gastroliths. TMP 2007.011.
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Front paws Brown bears have very large and curved claws, those present on the forelimbs being longer than those on the hind limbs. They may reach and may measure along the curve.Heptner, "Sirenia and carnivora (Sea cows; Wolves and Bears)" They are generally dark with a light tip, with some forms having completely light claws. Brown bear claws are longer and straighter than those of American black bears (Ursus americanus).
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In 1982, she was criticised by Samuel Tarsitano, Eberhard Frey and Jürgen Riess, who claimed that, while the muscles at the underside of the shoulder and pelvic plates were clearly powerful enough to pull the limbs downwards, comparable muscle groups on the top of these plates to elevate the limbs were simply lacking, and, had they been present, could not have been forcefully employed, their bulging carrying the danger of hurting the internal organs. They proposed a more limited flying model in which a powerful downstroke was combined with a largely unpowered recovery, the flipper returning to its original position by the momentum of the forward moving and temporarily sinking body. This modified flying model became a popular interpretation. Less attention was given to an alternative hypothesis by Stephen Godfrey in 1984, which proposed that both the forelimbs and hindlimbs performed a deep paddling motion to the rear combined with a powered recovery stroke to the front, resembling the movement made by the forelimbs of sea-lions.
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The symphyseal shelf at the front of the dentary may have given some ability for crushing, but as this was a relatively small area, it was probably not the main function of the jaws. The fact that most oviraptorids have been found in sediments that are interpreted as having been xeric and arid or semi-arid environments also argues against them having been specialised eaters of shellfish and eggs, as it is unlikely there would have been enough of these items under such conditions to support them. Longrich and colleagues pointed out that the robust forelimbs and enlargement of a single finger in heyuannine oviraptorids is similar to that seen in modern animals that eat ants and termites, such as anteaters and pangolins, but the morpholology of heyuannine jaws does not support them being insectivorous. The researchers found that the function of heyuannine forelimbs was unclear, but suggested that they could have been used for scratching, tearing, or digging, though not prey capture.
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Life restoration Fossils that are now known under the name Wintonotitan were first found in 1974 by Keith Watts. At the time, the specimens were assigned to an Austrosaurus sp., Austrosaurus then being the only named Australian Cretaceous sauropod genus. These fossils, catalogued as QMF 7292, consisted of a left shoulder blade, much of the forelimbs, a number of back, hip, and tail vertebrae, part of the right hip, ribs, chevrons, and unidentifiable fragments.
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Suchomimus's narrow skull was perched on a short neck, and its forelimbs were powerfully built, bearing a giant claw on each thumb. Along the midline of the animal's back ran a low dorsal sail, built from the long neural spines of its vertebrae. Like other spinosaurids, it likely had a diet of fish and small prey animals. Some palaeontologists consider the animal to be an African species of the European spinosaurid Baryonyx, B. tenerensis.
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The small-toothed sportive lemur has a dark stripe in the center of its forehead that lightens as it runs down the back. Its pelage (fur) is thick and reddish-brown, while its underside and neck are pale gray-brown, and sometimes have a yellowish or yellowish-gray hue. The shoulders and forelimbs have a bright chestnut color. The color darkens to russet between the shoulders, down to the hind-limbs and tail.
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The gestation period is about forty days and the litter size ranges from two to five. There is a single litter in the year and a long developmental period before the young are weaned. When first born, the young have hind legs the same length as their forelegs and as they begin to move around, do so by dragging themselves with their forelimbs. The hind legs gradually lengthen and by four weeks, quadrupedal locomotion starts.
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Western jumping mice resemble typical mice in appearance, but with long hind-feet and reduced forelimbs. They range from in total length, including a tail long, and weigh from . The mouse has coarse, dark-greyish-brown fur over the upper body, with a broad yellow to red band along the flanks, and pale yellowish-white underparts. Some individuals have white spots on the upper body, or on the tip of the tail.
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There was developed attachment for all the scapulohumeral muscles, particularly the deltoids. When extending the forelimbs, the deltoids may have raised the front side (anterior margin) of the humerus, and coracobrachialis muscle lowered the back side (posterior margin). When retracting the forelimb, the pectoralis muscle may have pushed the anterior margin down, and the subscapularis muscle pulled the posterior margin up. The pelvis joint has the usual ball-and-socket joint configuration.
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Beaver primarily develop canals to increase accessibility of river resources, facilitate transport of acquired resources, and to decrease the risk of predation. Beaver canals can be over 0.5 km in length. Beavers build canals by pushing through soil and vegetation using their forelimbs. It has been hypothesized that beavers' canals are not only transportation routes to extend foraging, but also an extension of their "central place" around the lodge and/or food cache.
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What had become walking limbs in cetaceans and seals evolved independently into new forms of swimming fins. The forelimbs became flippers, while the hindlimbs were either lost (cetaceans) or also modified into flipper (pinnipeds). In cetaceans, the tail gained two fins at the end, called a fluke.Felts WJL "Some functional and structural characteristics of cetacean flippers and flukes" Pages 255–275 in: Norris KS (ed.) Whales, Dolphins, and Porpoises, University of California Press.
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But this time, for his own "Pro-Avis" restoration, Nopcsa suggested a cursorial origin, not arboreal. The "Pro-Avis" would thus have been a running animal, accelerating and prolonging its jumps by flapping with feathered forelimbs. There is a model of Nopcsa's restoration, still preserved, and recently restored, in the Grant Museum of Zoology,Proavis wax model, as mentioned and described in the Tales of Things website. the only remaining university zoological museum in London.
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Most species have a dorsal fin to prevent themselves from turning upside-down in the water. The flukes of sirenians are raised up and down in long strokes to move the animal forward, and can be twisted to turn. The forelimbs are paddle-like flippers which aid in turning and slowing. Semi-aquatic mammals, like pinnipeds, have two pairs of flippers on the front and back, the fore-flippers and hind-flippers.
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Life restoration depicting swimming pose As a spinosaurid, Spinosaurus would have had a long, muscular neck, curved in a sigmoid, or S-shape. Its shoulders were prominent, and the forelimbs large and stocky, bearing three clawed digits on each hand. The first finger (or "thumb") would have been the largest. Spinosaurus had long phalanges (finger bones), and only somewhat recurved claws, suggesting that its hands were longer compared to those of other spinosaurids.
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Drawing of an African civet Skeleton of an African civet The African civet has a coarse and wiry fur that varies in colour from white to creamy yellow to reddish on the back. The stripes, spots, and blotches are deep brown to black. Horizontal lines are prominent on the hind limbs, spots are normally present on its midsection and fade into vertical stripes above the forelimbs. Its muzzle is pointed, ears small and rounded.
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Youngosuchus is known from a well-preserved skeleton recovered from the Kelamayi Formation in the Junggur Basin of Xinjiang, China. The skeleton, referred to as IVPP V 3239, includes a complete skull, cervical vertebrae, ribs, the pectoral girdle, and forelimbs. Youngosuchus has a large, deep skull with sharp recurved teeth. Osteoderms are not present on the skeleton, a possible indication that Youngosuchus did not have the body armor present in other early archosauriforms.
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While the shoulder and pelvic girdles are missing with the exception of one ilium, the limbs are better known, including the humerus, ulna, radius, thigh bone, tibia, fibula, astragalus, and a claw from the hind foot. The forelimbs were proportionally longer than in the shortnecked Shunosaurus, but shorter than in Omeisaurus: the length ratio between humerus and thigh bone was 0.72 in Yuanmousaurus, while it was 0.56 in Shunosaurus and 0.80 in Omeisaurus.
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This is unlike modern kangaroos, which use pentapedal motion, or 'punting', pushing off their tail and forelimbs and swinging their hindlimbs forward when moving slowly. It is thought that, by rearing up on their hind limbs and using their long arms and fingers, they could reach overhead to grasp high leaves and branches and pull them down to their mouth. They then would use their powerful jaws and striated teeth to grind the tough leaves.
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Comparative anatomy has long served as evidence for evolution, now joined in that role by comparative genomics; it indicates that organisms share a common ancestor. It also assists scientists in classifying organisms based on similar characteristics of their anatomical structures. A common example of comparative anatomy is the similar bone structures in forelimbs of cats, whales, bats, and humans. All of these appendages consist of the same basic parts; yet, they serve completely different functions.
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National Wildlife 39 (1) (December/January), 54–59 The skeleton of the killer whale is of the typical delphinid structure, but more robust. Its integument, unlike that of most other dolphin species, is characterized by a well-developed dermal layer with a dense network of fascicles of collagen fibres. Killer whale pectoral fins, analogous to forelimbs, are large and rounded, resembling paddles, with those of males significantly larger than those of females.
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At slow speeds, it employs pentapedal locomotion, using its tail to form a tripod with its two forelimbs while bringing its hind feet forward. Both pentapedal walking and fast hopping are energetically costly. Hopping at moderate speeds is the most energy efficient, and a kangaroo moving above maintains energy consistency more than similarly- sized animal running at the same speed. Kangaroos are adept swimmers, and often flee into waterways if threatened by a predator.
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In comparison with extant Leptoptilos, L. patagonicus is larger than L. javanicus and similar in size to the largest members of L. dubius and L. crumeniferus. In comparison with extant Leptoptilos, the hindlimbs are larger than the forelimbs, resulting in shorter wings relative to extant Leptotilos, a characteristic shared by the extinct Leptoptilos falconeri. L. patagonicus is smaller than L. falconeri. The humerus and ulna are shorter than those of L. dubius and L. crumeniferus.
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Fabrosaurids were relatively small ornithischian dinosaurs, averaging about 1–2 meters in body length, with a triangular skull that had large circular orbits on the sides. This suggests that fabrosaurids had relatively huge eyes that faced laterally. The forelimbs of fabrosaurids are considerably shorter than their hindlimbs. A small forelimb such as those present in Fabrosauridae would not have been useful for locomotion, and it is evident that fabrosaurids were bipedal dinosaurs.
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Size compared to a human Nanosaurus is known from material from all parts of the body, including two good skeletons, although the skull is still poorly known. It was a small animal, 2 meters (6.6 ft) or less in length and 10 kilograms (22 lb) or less in weight. It was a bipedal dinosaur with short forelimbs and long hindlimbs with large processes for muscle attachments. The hands were short and broad with short fingers.
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T. edmontoni also came from the Horseshoe Canyon Formation. It was based on NMC 8399, another nearly complete skeleton lacking most of the tail. NMC 8399 was discovered on the Red Deer River in 1912 by a Sternberg party. Its forelimbs, ossified tendons, and skin impressions were briefly described in 1913 and 1914 by Lambe, who at first thought it was an example of a species he'd named Trachodon marginatus, but then changed his mind.
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C. nasicornis had larger teeth than Allosaurus, and some paleontologists postulate that it would have had a difficult time attacking larger prey. Abelisaurids, however, carried many of these defining traits to their extremes. Most abelisaurids had largely shortened forelimbs, with Carnotaurus having shrunk them further than any large theropod. After analyzing the features of the newly discovered Rugops primus, Paul Sereno has postulated that many of these abelisaurid features may lend themselves to scavenging.
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Sun bears get their name from the characteristic orange to cream coloured chest patch. Its unique morphology—inward-turned front feet, flattened chest, powerful forelimbs with large claws—suggests adaptations for climbing. The most arboreal (tree-living) of all bears, the sun bear is an excellent climber and sunbathes or sleeps in trees above the ground. It is mainly active during the day, though nocturnality might be more common in areas frequented by humans.
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For instance, multiple ichnites of a single species, close together, suggest 'herd' or 'pack' behaviour of that species. Combinations of footprints of different species provide clues about the interactions of those species. Even a set of footprints of a single animal gives important clues, as to whether it was bipedal or quadrupedal. In this way, it has been suggested that some pterosaurs, when on the ground, used their forelimbs in an unexpected quadrupedal action.
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Rabbits and hares move by jumping, pushing off with their strong hind legs and using their forelimbs to soften the impact on landing. Pikas lack certain skeletal modifications present in leporids, such as a highly arched skull, an upright posture of the head, strong hind limbs and pelvic girdle, and long limbs. Also, pikas have a short nasal region and entirely lack a supraorbital foramen, while leporids have prominent supraorbital foramina and nasal regions.
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Both knees are drawn forwards, while the forelimbs are outstretched. Although the tail curves upwards and forwards over the body in many dinosaur skeletons, it was probably straight in the mummy as movement would have been restricted by . Almost two-thirds of the total skin area is preserved, often with excellent preservation. The skin impressions are pressed tightly onto the bones, and are partially drawn into the body in between the bones.
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Amphibians breathe by means of buccal pumping, a pump action in which air is first drawn into the buccopharyngeal region through the nostrils. These are then closed and the air is forced into the lungs by contraction of the throat. They supplement this with gas exchange through the skin which needs to be kept moist. In frogs the pelvic girdle is robust and the hind legs are much longer and stronger than the forelimbs.
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Acteosaurus is described as slender or snake-like, similar to other dolichosaurids. Its shortened forelimbs and long tail help to distinguish it from other genera, and its vertebral column is similar to more modern varanid lizards. The holotype, when it was discovered, was unfortunately missing its head. So, while Meyer was unable to come up with an exact number, he noted that Acteosaurus has at least 10 cervical vertebrae, and 27 dorsals.
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With a few exceptions, frogs use external fertilisation. The male grasps the female tightly with his forelimbs either behind the arms or in front of the back legs, or in the case of Epipedobates tricolor, around the neck. They remain in amplexus with their cloacae positioned close together while the female lays the eggs and the male covers them with sperm. Roughened nuptial pads on the male's hands aid in retaining grip.
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It is thought they may have propelled themselves with their forelimbs, dragging their hindquarters in a similar manner to that used by the elephant seal. In the early Carboniferous (360 to 345 million years ago), the climate became wet and warm. Extensive swamps developed with mosses, ferns, horsetails and calamites. Air-breathing arthropods evolved and invaded the land where they provided food for the carnivorous amphibians that began to adapt to the terrestrial environment.
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Daspletosaurus is closely related to the much larger and more recent tyrannosaurid Tyrannosaurus rex. Like most tyrannosaurids, Daspletosaurus was a multi-tonne bipedal predator equipped with dozens of large, sharp teeth. Daspletosaurus had the small forelimbs typical of tyrannosaurids, although they were proportionately longer than in other genera. As an apex predator, Daspletosaurus was at the top of the food chain, probably preying on large dinosaurs like the ceratopsid Centrosaurus and the hadrosaur Hypacrosaurus.
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Tetrapods were initially understood to have first developed five digits as an ancestral characteristic, which were then reduced or specialized into a number of uses. Certain animals retained 'primitive' forelimbs, such as pentadactylous (five-fingered) reptiles and primates. This has mostly held true, but the earliest tetrapod or "fishapod" ancestors may have had more than five digits. This was notably challenged by Stephen Jay Gould in his 1991 essay "Eight (Or Fewer) Little Piggies".
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Solenodons find food by sniffing the ground until they come upon their prey. If the prey is small enough, the solenodon will consume it immediately. After coming across the prey, the solenodon will bring the forelimbs up to either side of the prey and then move the head forward, opening the jaw and properly catching its prey. While sniffing for food, the solenodon can get through physical barriers with the help of its sharp claws.
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Five digits were found on both the hind limbs as well as the forelimbs. In order to counterbalance the weight of its body, Hesperosuchus is inferred to have had a relatively long tail. Since the caudal vertebrae aren't completely restored, it is inferred based on similar archosaurians, that the tail contained somewhere around 45 caudal vertebrae. The strong hind limbs and overall light weight made Hesperosuchus very quick and able to move rapidly.
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Asymmetrical gaits are sometimes termed "leaping gaits", due to the presence of a suspended phase. The key variables for gait are the duty factor and the forelimb-hindlimb phase relationship. Duty factor is simply the percent of the total cycle which a given foot is on the ground. This value will usually be the same for forelimbs and hindlimbs unless the animal is moving with a specially trained gait or is accelerating or decelerating.
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This species is nocturnal and breeds in streams and pools. Males congregate in vegetation a few metres above a water body and call to attract the females. They continue to call for a few days, or up to three months, from their favoured locations (average 36 days). They engage in fights with rival males, dangling from twigs and leaves with their hind limbs while using the spurs on their forelimbs to engage.
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A variety of behaviours exhibited by dogs can be interpreted to convey certain emotions. A well-known behaviour associated with playful moods in dogs is known as a play bow, where a dog lowers its forelimbs and chest while raising its hind end and wagging its tail. This may be followed with other playful actions, such as bouncing movements and face pawing. In young dogs, urination can be a behaviour associated with submission.
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Wings, which evolved from forelimbs, gave birds the ability to fly, although further evolution has led to the loss of flight in some birds, including ratites, penguins, and diverse endemic island species. The digestive and respiratory systems of birds are also uniquely adapted for flight. Some bird species of aquatic environments, particularly seabirds and some waterbirds, have further evolved for swimming. Birds are a group of feathered theropod dinosaurs, and constitute the only living dinosaurs.
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This deletion includes the H2AFY gene, which is responsible for suppressing an upstream enhancer element known as hs1473. When H2AFY is removed, the enhancer is brought closer to PITX1 and inappropriately enhances it in forelimbs, causing them to adopt hindlimb morphology. The second mutation that can cause the phenotype for Liebenberg syndrome is a translocation of chromosome 18 and chromosome 5. Translocation mutations are ones that switch parts of non-homologous chromosomes with each other.
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The eyes are small, and the ears are little more than ridges on the skin, another possible adaptation to avoiding damage while fighting. The honey badger has short and sturdy legs, with five toes on each foot. The feet are armed with very strong claws, which are short on the hind legs and remarkably long on the forelimbs. It is a partially plantigrade animal whose soles are thickly padded and naked up to the wrists.
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Antetonitrus is a genus of sauropod dinosaur found in the Early Jurassic Elliot Formation of South Africa. The only species is Antetonitrus ingenipes. As one of the oldest known sauropods, it is crucial for the understanding of the origin and early evolution of this group. It was a quadrupedal herbivore, like all of its later relatives, but shows primitive adaptations to use the forelimbs for grasping, instead of purely for weight support.
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The forelimbs were shorter than the hindlimbs, which resulted in an arched back, with the highest point over the hips. Its feet, limbs, shoulders, and pelvis were all very stoutly constructed and reinforced to support a great deal of weight. American paleontologist Ken Carpenter estimated the mass of S. edwardsorum at 1,500 kilograms (3,300 lb). Restoration Like other nodosaurids, Sauropelta was covered in armor formed from bony masses embedded in the skin (osteoderms).
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A kea in flight. The bird's forelimbs (the wings) are the key to flight. Each wing has a central vane to hit the wind, composed of three limb bones, the humerus, ulna and radius. The hand, or manus, which ancestrally was composed of five digits, is reduced to three digits (digit II, III and IV or I, II, III depending on the scheme followedBaumel JJ (1993) Handbook of Avian Anatomy: Nomina Anatomica Avium.
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These adaptations are also paralleled in many living mammalian herbivores of different lineages. Modern cows, horses, and white rhinoceros all exhibit wide muzzles and all are grazing animals. Grazing most often occurs at ground level, and if the expanded muzzles of Altirhinus and other related species were an adaptation to grazing, this may also explain corresponding weight-bearing adaptations of the forelimbs in derived iguanodontians, in order to get the head closer to the ground.
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The torso of Coelophysis conforms to the basic theropod body shape, but the pectoral girdle displays some interesting special characteristics: C. bauri had a furcula (wishbone), the earliest known example in a dinosaur. Coelophysis also preserves the ancestral condition of possessing four digits on the hand (manus). It had only three functional digits, the fourth embedded in the flesh of the hand. Coelophysis had narrow hips, forelimbs adapted for grasping prey, and narrow feet.
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Homotherium had the general appearance of a cat, but had a number of atypical features for a felid. Homotherium had unusual limb proportions, with longer, more robust forelimbs that gave it a hyena-like appearance. The hind quarters were rather squat with feet that may have been partially plantigrade, causing the back to slope towards the short tail. Features of the hind limbs indicate that this cat was moderately capable of leaping.
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This species is sometimes confused with the Karoo padloper (H. boulengeri) which inhabits the Karoo region to the west. However greater padlopers can be distinguished not only by their larger size, but also by their nostrils which are below their eye level, by their having four toes on both their front and back feet, by the larger scales on their forelimbs, and by the darker rings around the shell scutes of many individuals.E.H.W. Baard (1994).
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Gryponyx africanus is known from the holotype SAM 3357-59, a nearly complete postcranial skeleton which includes partial vertebral column, pelvis, both forelimbs and both hindlimbs. Gryponyx has been estimated to have been about in length. It was collected from the Upper Elliot Formation of the Stormberg Group (Karoo Basin), dating to the Hettangian to Sinemurian stages of the Lower Jurassic period. It was originally described by Broom (1911) as a theropod.
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Unlike in Amargasaurus, this spine was bowed frontward and broadened toward the tips. The last two dorsal vertebrae, the hip, and the foremost tail in Amargasaurus also had elongated spines; these were not bifurcated but flared into a paddle-shaped upper end. The pelvic region was relatively wide, judging from the long, laterally projecting transverse processes of the sacral vertebrae. The forelimbs were somewhat shorter than the hind limbs, as in related sauropods.
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A study showed that deletion of Tbx5 in forelimbs causes disruption in the muscle and tendon patterning without affecting the skeletons development. Tbx5 expression is in the cells of the lateral plate mesoderm which form the forelimb bud and the cascade of limb initiation. In its absence no forelimb bud forms. Diseases and defects associated with this gene are Holt-Oram syndrome, both have to do with limb defects and several other abnormalities.
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However, each of these four species' forelimbs performs a different task. The same bones that construct a bat's wings, which are used for flight, also construct a whale's flippers, which are used for swimming. Such a "design" makes little sense if they are unrelated and uniquely constructed for their particular tasks. The theory of evolution explains these homologous structures: all four animals shared a common ancestor, and each has undergone change over many generations.
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Vestigial forelimbs and axial elongation in a 95 million-year-old non-snake squamate. Journal of Vertebrate Paleontology, 27(1), 1-7. However, the validity of Pythonomorpha is still debated; indeed, there is no consensus about the relationships of snakes or mosasaurs to each other, or to the rest of the lizards. An analysis by Conrad (2008) placed mosasaurs with varanoid lizards, and snakes with skinks, while an analysis by Gauthier et al.
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In the tail-straddling walk, the male release the female and slides his head under her chin, then her forelimbs straddle the male's tail and the pair then move forward. The male then deposits a spermatophore on the ground which is followed by the female picking up a sperm cap with her cloacal lips as she moves forward undulating her pelvic area.Organ, J. A. 1961. Life History of the Pigmy Salamander, Desmognathus wrighti, in Virginia.
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However, it has been suggested by Robert Thomas Bakker that stegosaurians could rear on their hind legs to reach higher layers of plants, the tail then being used as a "third leg". The mobility of the tail was increased by a reduction or absence of ossified tendons, that with many Ornithischia stiffen the hip region. Huayangosaurus still possessed them. In species that had short forelimbs, the relatively short torso towards the front curved strongly downwards.
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The forelimbs are not flattened into paddles as in metriorhynchids, but the ulna (lower arm bone) is reduced in length, indicating that forelimb reduction began at the lower limb and progressed upward (the humerus or upper arm bone of Zoneait not reduced). Taken together, the transitional features of Zoneait indicate that metriorhynchoids' adaptation of a marine lifestyle began with a shift in feeding ecology and only later involved changes in swimming locomotion.
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Corythosaurus is now thought to be a lambeosaurine, related to Nipponosaurus, Velafrons, Hypacrosaurus, and Olorotitan. Corythosaurus has an estimated length of , and has a skull, including the crest, that is tall. Corythosaurus is known from many complete specimens, including the nearly complete holotype found by Brown in 1911. The holotype skeleton is only missing the last section of the tail, and part of the forelimbs, but was preserved with impressions of polygonal scales.
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However, such frame shifts are rare in amniotes and—to be consistent with the theropod origin of birds—would have had to occur solely in the bird-theropod lineage forelimbs and not the hindlimbs (a condition unknown in any animal).Developmental Biology 8e Online. Chapter 16: Did Birds Evolve From the Dinosaurs? This is called Lateral Digit Reduction (LDR) versus Bilateral Digit Reduction (BDR) (see also LimusaurusVargas AO, Wagner GP and Gauthier, JA. 2009.
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Dinosauriformes is a clade of archosaurian reptiles that include the dinosaurs and their most immediate relatives. All dinosauriforms are distinguished by several features, such as shortened forelimbs and a partially to fully perforated acetabulum, the hole in the hip socket traditionally used to define dinosaurs. The oldest known dinosauriform is Asilisaurus, a silesaurid which may have lived as early as the Anisian age of the middle Triassic period, about 245 million years ago.
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Life restoration of M. lilloensis with featherlike filaments In terms of proportions, Marasuchus generally resembled early theropod dinosaurs like Coelophysis. The limbs were long and slender, with the hindlimbs about twice the length of the forelimbs. These proportions meant that it was probably bipedal and had acquired the upright stance characteristic of dinosaurs. The neck was long, with an S-shaped curve as its default position, while the tail was very long and thin, though deeper at its base.
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One small specimen was also found in Tsaagan Khushuu the same year, and another small specimen was found in the Nemegt locality. A small skeleton without forelimbs was discovered in 1967 by the Mongolian palaeontological expedition in Bugeen Tsav outside the Nemegt Basin. The fossils were housed at the Mongolian, Polish and USSR Academy of Sciences. The Polish-Mongolian expeditions were notable for being led by women, some of whom were among the first women to name new dinosaurs.
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It was connected relatively weakly with the coracoid, which was large and deep from top to bottom. Overall, the forelimbs did not differ much from those of other ornithomimids, all of which were comparatively weak. The humerus (upper arm bone), which had a near circular cross-section, was long and twisted. The deltopectoral crest on the upper front part of the humerus was comparatively small, and therefore provided little surface for attachment of upper arm muscles.
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John Wiley & Sons, New York 1:1–600 1 90. and the tail, often naked and white, has a length that is half the head and body of this species. This pocket gopher is well adapted to burrowing, which is evident in the characteristic stocky build, fusiform shape, powerful jaws and incisors, large powerful forelimbs, and reduced hind limbs and hips often observed in this species. The diet of this species includes roots of xerophytic shrubs, grasses, and forbs.
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Ophidiomorpha is a clade composed of snakes and their primitive and early relatives proposed by Palci and Caldwell (2007)Palci, A., & Caldwell, M. W. (2007). Vestigial forelimbs and axial elongation in a 95 million-year-old non- snake squamate. Journal of Vertebrate Paleontology, 27(1), 1-7. The clade was defined as a node-based clade containing the most recent common ancestor of dolichosaurs, adriosaurs, Aphanizocnemus, and fossil and extant Ophidia and all of its descendants.
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New York: Kingfisher Books. Chicago / Turabian - Author Date Citation The scapular blade of Piatnitzkysaurus is shorter and wider than more derived tenaurans. The humerus represents 50 percent of the length of the femur, which is also a primitive condition present among basal theropods. The relative lengths of the ulna in respect to the humerus and femur are also similar to those of basal theropods, which means the forelimbs of Piatnitzkysaurus are proportionally longer than in Allosaurus.
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Size of L. huenei (light green) and L. magnus (dark green) Lufengosaurus is often described as a rather small early sauropodomorph, about long. However, when the L. magnus specimens are included, its size is more considerable: Gregory S. Paul estimated a length of and a weight of in 2010.Paul, G.S., 2010, The Princeton Field Guide to Dinosaurs, Princeton University Press p. 135 For an early sauropodomorph, its neck is rather long and the forelimbs are relatively short.
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The Hula painted frog has a dark belly with small white spots. It is colored ochre above with a rusty colour grading into dark olive-grey to greyish-black on the sides. Differences from the common painted frog (Discoglossus pictus) include its greater interocular distance, longer forelimbs, and a less projecting snout. The type specimen was an adult female with a body length of Little is known about its history, because few specimens have been found by scientists.
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A structure can be homologous at one level, but only analogous at another. Pterosaur, bird and bat wings are analogous as wings, but homologous as forelimbs because the organ served as a forearm (not a wing) in the last common ancestor of tetrapods, and evolved in different ways in the three groups. Thus, in the pterosaurs, the "wing" involves both the forelimb and the hindlimb. Analogy is called homoplasy in cladistics, and convergent or parallel evolution in evolutionary biology.
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Like most eutriconodonts, Spinolestes was animalivorous, probably an insectivore. It was a terrestrial animal with some adaptations for fossoriality, possessing strong forelimbs with large claws. This, alongside the convergent traits with xenarthrans may indicate that it was ecologically similar to modern anteaters, pangolins, echidnas, aardvark, aardwolf and numbat, feeding on colonial insects like ants and termites. If this is the case, it would be the second known Mesozoic mammal to pursue such a diet after Fruitafossor.
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They congregate to breeding ponds depending on the heavy spring and early summer rains. The G. carolinensis species is particularly successful at breeding in ephemeral bodies of water. When the male amplexes the female, special glands in the sternal region of males secretes a sticky substance to allow adhesion of breeding pairs, and also presumably to help him resist other males’ attempts to dislodge him. Breeding grasp (amplexus) for the toad species is axillary (behind the forelimbs).
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If not, they are more likely to become unavailable later on. Load carrying affects limb mechanics by increasing the force on the lower limbs, which may affect the evolution of anatomy in facultatively bipedal primates. Possible selective pressures for facultative bipedalism include resource gathering, such as food, and physical advantages. Great apes that engage in male-male fights have an advantage when standing on their hind legs, as this allows them to use their forelimbs to strike their opponent.
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Beyond that, uphill build, high-set neck, a mobile head-neck connection and long legs are more important in dressage horses than jumping horses. The musculature and outline of the back and loin, called the topline, is important to most registries, as are large joints and hooves with "dry" legs. Conformation scores are usually broken down further to allow breeders to compare specific traits in horses - for instance the "forelimbs" and "hindlimbs" are almost always awarded separate scores.
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It had a disproportionately long neck, small skull, and large overall size, all of which are typical for sauropods. Atypically, Brachiosaurus had longer forelimbs than hindlimbs, which resulted in a steeply inclined trunk, and a proportionally shorter tail. Brachiosaurus is the namesake genus of the family Brachiosauridae, which includes a handful of other similar sauropods. Most popular depictions of Brachiosaurus are in fact based on Giraffatitan, a genus of brachiosaurid dinosaur from the Tendaguru Formation of Tanzania.
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The younger specimen of Patagosaurus possesses a slightly different morphology of the pectoral girdle, with slightly differing proportions, such as a slightly smaller scapular blade. The coracoids resemble Barapasaurus in shape, and differ from Camarasaurus, although they cannot be directly compared with those of Cetiosaurus. The forelimbs of Patagosaurus are only based on three bones from the juvenile specimen, and no manual elements are preserved. The humeri are slender and elongate, lacking great proximal and distal expansions.
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The discovery of Jianianhualong supports the notion that asymmetrical feathers appeared early in the evolutionary history of the Paraves. Jianianhualong possesses a combination of traits seen in basal as well as traits seen in derived troodontids. This is consistent with its phylogenetically intermediate position among the troodontids. This mixture of traits shows a distinct spatial organization, with basal traits being present in the forelimbs and pelvis, and derived traits being present in the skull and hindlimbs.
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It was a hunter which probably preyed on large large bulky herbivores like dicynodonts and many other creatures smaller than itself (such as early dinosaurs). The skeleton of Postosuchus is large and robust with a deep skull and a long tail. The total body length is about . The extreme shortness of the forelimbs relative to the hind limbs, the very small hands, and measurements of the vertebrae suggest that Postosuchus may have been committed to bipedal locomotion.
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After reaching its maximum height, the AER in mouse limb buds flattens and eventually become indistinguishable from the dorsal and ventral ectoderm. The structure of the human AER is similar to the mouse AER. In addition to wings in chicks and forelimbs in mice, pectoral fins in zebrafish serve as a model to study vertebrate limb formation. Despite fin and limb developmental processes share many similarities, they exhibit significant differences, one of which is the AER maintenance.
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It had thick horns above the eyes, a feature unseen in all other carnivorous dinosaurs, and a very deep skull sitting on a muscular neck. Carnotaurus was further characterized by small, vestigial forelimbs and long, slender hindlimbs. The skeleton is preserved with extensive skin impressions, showing a mosaic of small, non-overlapping scales approximately 5 mm in diameter. The mosaic was interrupted by large bumps that lined the sides of the animal, and there are no hints of feathers.
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Unlike galagos, which have longer legs than arms, slow lorises have arms and legs of nearly equal length. Their intermembral index (ratio of arm to leg length) averages 89, indicating that their forelimbs are slightly shorter than their hind limbs. As with the slender lorises, their arms are slightly longer than their body, but the extremities of slow lorises are more stout. Slow lorises have a powerful grasp with both their hands and feet due to several specializations.
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Snakes, which are closely related to mosasaurs, have only one functional lung with the second often being vestigial or absent. Unlike terrestrial lizards, however, the bronchi separate in front of the area of the forelimbs rather than at the level of the limbs. Soft tissues in the head and neck of specimen LACM 128319: Tracheal rings are shown in the bottom three photographs. Skin impressions are known from Platecarpus, preserved in LACM 128319 as soft impressions and phosphate material.
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Wannchampsus is based on SMU 76604, a partial skull and lower jaw. This fossil is attached by matrix to another partial skull of the same genus and species, SMU 76605\. A handful of other fossils were found associated, mostly representing forelimbs and vertebrae. These fossils were found in rocks of the late Aptian-age Lower Cretaceous Twin Mountains Formation, southwest of Stephenville, in Comanche County, Texas; the site is otherwise known as the Proctor Lake dinosaur locality.
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Bipes is a genus of amphisbaenians found only in Mexico, the sole living member of the family Bipedidae. Commonly known as ajolotes, they are carnivorous, burrowing reptiles, but unlike other species of amphisbaenians, they possess two stubby forelimbs placed far forward on the body. The shovel- like limbs are used to scrape away soil while burrowing, in a manner similar to a mole. Evidence for their occurrence in the United States is reviewed by Somma (1993).
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It had a typical anomodont phalangeal formula of 2-3-3-3-3 on its forelimbs. While the hind limbs were not preserved well enough to know for certain, it appears that this formula was present on the hind limbs as well. Both the fore and hind limbs possessed extended phalanges with long, flattened claws, which suggests that Eosimops was a digger. It had short limbs, and it likely had a sprawling posture similar to its close relative Diictodon.
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The foot is elongate with pointed claws and does not appear to be particularly specialized. The shoulder girdle and forelimbs are more representative of Dicynodontia as a whole than the hindlimbs. The girdle is high and narrow, reflecting a reduction in the backward-forward pulling muscles, which would have been situated above and below the humerus. The humerus suggests an emphasis of long-axis rotation, a much more conservative morphology than that of the hindlimb structure.
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The Japanese common toad can reach a snout–to–vent length of up to about , with females being a little larger than males, and toads living in warmer habitats growing larger than those in colder places. The head has a pointed snout and is roughly triangular. The tympanum is elliptical and about as far behind the eye as its longest diameter. The body is robust and the stout forelimbs are about half as long as the hind limbs.
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The New Zealand mantis has a triangular head with slightly oversized compound eyes that give it excellent binocular vision (although they do have a blind spot). Its wings differ from those of other species in the "development of the archedictyon and the absence of cross-veins in the forewing". "A very active little Mantis", O. novaezealandiae is well adapted as a predator. Its specialized forelimbs are long and equipped with extremely sharp spikes to trap prey.
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Cistecephalus is an extinct genus of dicynodont therapsid from the Late Permian of southern Africa (South Africa and Zambia). It was a small, specialised, burrowing dicynodont, possibly with habits similar to a modern mole. The head was flattened and wedge-shaped, the body long, and the forelimbs very strong, with similarities in structure to the forelimb of modern burrowing mammals. It was one of the first genera of dicynodonts to be described, by Richard Owen, in 1876.
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Large individuals have smaller feet in relation to their hindlimbs than small individuals, while small individuals have proportionally shorter forelimbs relative to their hindlimbs. Liushusaurus may have been sexually dimorphic, as specimens have been found with possible post-cloacal bones that would indicate they are males. These bones are seen in some living lizards such as gekkotans. Specimens with these bones tend to be the largest individuals, suggesting that males may have been larger than females.
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There are small articular processes on the trunk vertebrae, and it has long, narrow neural spines, and posteroventrally positioned, unfused haemal arches on the vertebrae of the tail. There is no pachyostosis, or bone thickening, in the vertebrae and ribs. The limbs are reduced in size, and though the forelimbs of Acteosaurus are fully developed, they are smaller than the hind limbs. Acteosaurus' pelvic bone is flattened, has square-shaped pubic process, and a rectangular descending ramus.
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Finally, the spine length peaks over the forelimbs. The first four dorsal vertebrae are unknown; the fifth already bears a that is pointed and slightly hooked; Taquet presumed it might have anchored a tendon to support the neck or skull. The tenth, eleventh and twelfth spines are the longest, at about . The last dorsal spine, the seventeenth, has a grooved posterior edge, in which the anterior corner of the lower spine of the first sacral vertebra is locked.
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Later research shows them instead as being warm-blooded and having powerful flight muscles, and using the flight muscles for walking as quadrupeds. Mark Witton of the University of Portsmouth and Mike Habib of Johns Hopkins University suggested that pterosaurs used a vaulting mechanism to obtain flight. The tremendous power of their winged forelimbs would enable them to take off with ease. Once aloft, pterosaurs could reach speeds of up to and travel thousands of kilometres.
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Although very little information about the reproduction of highland frogs is available, it is believed that they breed by direct development. They lay their eggs under mulch and leaves, and a parent will guard the eggs. If threatened, the parent highland frog will raise itself on its forelimbs, and hiss at the potential predator to try to make it go away. The offspring, however, bypasses the larval stage and becomes a miniature adult when it hatches from its egg.
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Life reconstruction of Y. downsi Yinlong was a relatively small dinosaur, with a total length of about from nose to tail, and a weight of about . Long robust hindlimbs and shorter slender forelimbs with three-fingered hands suggests a bipedal lifestyle like many small ornithopods. Despite a virtually frill-less and totally hornless skull, Yinlong is a ceratopsian. Its skull is deep and wide and relatively large compared to most ornithischians, but also proportionately smaller than most other ceratopsians.
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Burramys parvis species will supplement their diet with the mountain plum pine from the fruit- bearing conifer Podocarpus lawrencei as well as seeds from the snow beard- heaths Leucopogon spp. and blackberry Rubus spp. Upon finding food, the mountain pygmy possum will first smell the food source before picking it up with its incisors. It will then transfer the item to its forelimbs so that it may manipulate the food and tear off pieces of flesh.
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Afrovenator is known from a single relatively complete skeleton, holotype UC OBA 1, featuring most of the skull minus its top (likewise the mandible, or lower jaws, are lacking apart from the prearticular bone), parts of the spinal column, partial forelimbs, a partial pelvis, and most of the hind limbs. This skeleton is housed at the University of Chicago. The generic name comes from the Latin afer, "African", and venator, "hunter". There is one named species, Afrovenator abakensis.
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Currently there is only one species belonging to the genus Grippia, this species is Grippia longirostris. Grippia longirostris was an entirely marine species and is considered to be the most basal example of Ichthyopterygia. G.longirostris measured in at 1-1.5m (3.3-4.9 feet) in length making it the smallest species within the superorder Ichthyopterygia. Other definitive features of G.longirostris include the arrangement of carpals and metacarpals that constitute the forelimbs and the morphology of the skull.
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One elongated neural spine indicates it may have had a hump or ridge along the centre of its back. It had robust forelimbs, with the eponymous first-finger claw measuring about long. Now recognised as a member of the family Spinosauridae, Baryonyx affinities were obscure when it was discovered. Some researchers have suggested that Suchosaurus cultridens is a senior synonym (being an older name), and that Suchomimus tenerensis belongs in the same genus; subsequent authors have kept them separate.
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Some animals can use their forelimbs (which are homologous to arms in humans) to carry and manipulate objects. Some animals can also use hind limbs for manipulation. Human legs and feet are specialized for two-legged locomotion – most other mammals walk and run on all four limbs. Human arms are weaker, but very mobile, allowing them to reach at a wide range of distances and angles, and end in specialized hands capable of grasping and fine manipulation of objects.
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As in other ceratosaurs, the shoulder blade (scapula) and shoulder girdle (coracoid) fuse into a single bone, the scapulocoracoid. This bone is very large and broad, even compared to the condition in other ceratosaurs. The scapula portion (above the glenoid, or arm socket) tapers towards the back while the coracoid portion (below the glenoid) is expanded into a curved blade-like structure. While abelisaurids have arms that are extremely reduced in size, Masiakasaurus and other noasaurids had longer forelimbs.
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Fossil claw, Tianjin Natural History Museum Hu considered Chilantaisaurus to be a carnosaur related to Allosaurus,Hu, S.-Y. (1964). "Carnosaurian remains from Alashan, Inner Mongolia." Vertebrata PalAsiatica, 8: 42–63. [In Chinese, with English summary] though some subsequent studies suggested that it may be a spinosauroid, possibly a primitive member of the spinosaurid family (Sereno, 1998; Chure, 2000; Rauhut, 2001) because it had large claws on the forelimbs thought to be unique to that group.
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The pectoral girdle had a robust and U shaped wishbone, a slightly curved shoulder blade, a short and robust coracoid and a broad and deeply notched breastbone. The hips had an unfused illium, a slender and curved pubis with a small pubic foot and a strap like ischium which is shorter than the pubis. The hind limb was shorter than the forelimb. The forelimbs had a humerus and a radus which were straighter and shorter than the ulna.
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Based on when molar crown initiation occurred, Megaladapis gestation period is thought to have been at least 198 days, but was likely longer. The island's topography was always changing, and like other lemurs, Megaladapis was specialized within its own niche. The general expectations of tree climbers such as Megaladapis is that with an increase in size, the body's forelimbs will also increase proportionally. Some exterior scratches and incisions were found on both its metatarsus and its mandibula.
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After this period, they begin to ingest small invertebrates, and actively forage about ten days after hatching. As in all salamanders and newts, forelimbs—already present as stumps at hatching—develop first, followed later by the back legs. Unlike smaller newts, Triturus larvae are mostly nektonic, swimming freely in the water column. Just before the transition to land, the larvae resorb their external gills; they can at this stage reach a size of in the larger species.
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The similarity of the forelimbs of Deinonychus (left) and Archaeopteryx (right) led John Ostrom to revive the link between dinosaurs and birds. The tide began to turn against the 'thecodont' hypothesis after the 1964 discovery of a new theropod dinosaur in Montana. In 1969, this dinosaur was described and named Deinonychus by John Ostrom of Yale University. The next year, Ostrom redescribed a specimen of Pterodactylus in the Dutch Teyler Museum as another skeleton of Archaeopteryx.
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Benson and colleagues also estimated the weight for the animal of AMNH 5214 at in 2014. restoration The structure of much of the skeleton of Ankylosaurus, including most of the pelvis, tail, and feet, is still unknown. It was quadrupedal, and its hind limbs were longer than its forelimbs. In specimen AMNH 5895, the scapula (shoulder blade) measures long and was fused with the coracoid (a rectangular bone connected to the lower end of the scapula).
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Several of Austroraptor's skull bones bear some resemblance to those of the smaller troodontids. The front limbs of Austroraptor were short for a dromaeosaur, with its humerus less than half the length of its femur. Among the Dromaeodauridae, only this genus, Tianyuraptor, Zhenyuanlong and Mahakala have similarly reduced forelimbs. The relative length of its arms has caused Austroraptor to be compared to another, more famous short-armed dinosaur, Tyrannosaurus, though there is no close relationship between the two taxa.
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The humerus bones are unique to shrew-moles because they exist as massive rectangular shapes, unlike other fossorial mammalian groups. The humerus also has a large surface area for the attachment of well developed muscles used for digging. The shrew- mole makes permanent tunnels by digging with its forelimbs and using its forefeet to soften the soil that will be removed to make a hollow tunnel. The tunnels form complex networks that interconnect and lead to burrows.
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20cm fossil Keichousaurus The locomotion of Keichousaurus probably resembled (in part) the "underwater flight" that plesiosaurs employed. The flattened forelimbs would likely have acted as hydrofoils. The hindlimbs show less specialization, and may therefore have acted as stabilizers and control surfaces, such as is seen in extant sea turtles. The intermediate nature of the limb morphology implies that there was also, to some extent, the kind of 'crawling through the water' seen in small freshwater turtles.
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A characteristic feature of baboons is their long molars and broad incisors. The long canines are evidence of sexual dimorphism in baboon species. Their forelimbs and hindlimbs are nearly equal in length and their digits on their hands and feet are relatively short and stout, making it difficult for them to climb. Baboons are one of the largest groups of monkeys and are sexually dimorphic in body size (meaning the males and females have differing body sizes).
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Their experiments with models showed that the reptile could glide with its uropatagium and stabilize its glide by changing the angles of its forelimbs to provide an aeronautic canard or by bending its tail up or down to produce drag. In 2006, Dyke et al. published a study on possible gliding techniques for Sharovipteryx. The authors found that the wing membrane, which stretched between its very long hind legs and tail, would have allowed it to glide as a delta wing aircraft does.
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It has a long flexible snout, typical of the elephant-shrews, which can be moved in a circular fashion and the nostrils are located towards the tip of the snout, with long sensory whiskers growing at the base of the snout. The rear legs are longer than the forelimbs, an adaptation for running and jumping. North African elephant-shrews use well-developed glands, placed under the tail, for marking territory. The adult specimen has 42 teeth, with a dental formula of .
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A skeletal diagram of Acherontiscus Adelospondyls share a variety of traits with other lepospondyls, although whether these traits are an example of convergent evolution is a controversial topic. Like the aïstopods and lysorophian "microsaurs", they had very elongated bodies similar to that of snakes and eels. In addition, they lacked limbs (similarly to the aïstopods), although forelimbs were supposedly found in various adelogyrinids in the late 1960s. Andrews & Carroll (1991) found that all cases of forelimb bones in adelogyrinids were actually misinterpretations.
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The first hadrosaur finds did not include much skull material. Hadrosaur teeth have been known since the 1850s (Joseph Leidy's Trachodon), and a few fragments of teeth and jaws were among the bones named Hadrosaurus by Leidy in 1858. (The skeletal mount made for Hadrosaurus by Benjamin Waterhouse Hawkins included a speculative iguana-like skull) Leidy had enough skeletal material to make other inferences about the paleobiology of hadrosaurs, though. Of particular importance was the unequal lengths of the forelimbs and hindlimbs.
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The tail is black and white with a distinct crest. Unlike bandicoots, they are excellent burrowers and can build extensive tunnel systems with their strong forelimbs and well-developed claws. A bilby typically makes several burrows within its home range, up to about a dozen; and moves between them, using them for shelter both from predators and the heat of the day. The female bilby's pouch faces backward, which prevents her pouch from getting filled with dirt while she is digging.
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The largest skull recorded for an Indian leopard belonged to a large black panther in the area of Ootacamund, which was recorded in 1920. The panther was said to have bigger forelimbs and forequarters than hind-limbs and hind-quarters, and a skull and claws about as large as those of a tigress. The skull measured in basal length, and in breadth, and weighed . To compare, the skull of a West African panther measured in basal length, and in breadth, and weighed .
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Lufengosaurus huenei pelvis. Like all early sauropodomorphs, Lufengosaurus had much longer hindlimbs than forelimbs and was probably bipedal. It was herbivorous, although it had sharp claws (with an especially large thumb claw) and teeth. These features have been used to support claims, the most recent by Cooper in 1981, that Lufengosaurus may have been at least partially omnivorous, but the sharp teeth witnessed in Lufengosaurus and other early sauropodomorphs are similar to those seen in iguanaian lizards – which are herbivorous.
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In mice, one gene known to regulate limb growth is prx1, which encodes a transcription factor. The expression patterns of prx1 in bats differs from mice in that prx1 has an expanded expression domain and is upregulated. Researchers found that the coding region of prx1 in bats is nearly identical to mice but found a bat-specific prx1 enhancer. When they replaced the bat prx1 enhancer with the endogenous enhancer found in mice, these transgenic mice had slightly increased forelimbs.
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The largest cause of poor performance in equine athletes is lameness caused by abnormalities in the muscular or skeletal systems. The majority of lameness is found in the forelimbs, with at least 95 percent of these cases stemming from problems in the structures from the knee down. Lameness in the hind limbs is caused by problems in the hock and/or stifle 80 percent of the time. There are numerous issues that can occur with horses' legs that may not necessarily cause lameness.
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In Central Asia, the sand cat's winter coat is very long and thick, with hairs reaching up to in length. The sand cat's claws on the forelimbs are short and very sharp, and claws on the hind feet are small and blunt. The undersides of its paws are protected from extreme temperatures by a thick covering of fur. The long hairs growing between its toes create a cushion of fur over the foot pads, helping to insulate them while moving over hot sand.
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Originally thought to be one of the earliest members of flightless birds, alvarezsaurids have recently been regarded as more basal theropods. Skeletal remains suggest that they had tiny but stout forelimbs and compact birdlike hands. The skeletal structure also suggests that this dinosaur possessed significant breast and arm muscles that were likely adapted for tearing and digging. They had elongate jaws with minute teeth and a tubular snout that suggests they could have been adapted to feed on insects such as termites.
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In many secondarily aquatic vertebrates, the non-bony tissues of the forelimbs and/or hindlimbs are fused into a single flipper. Some remnant of each digit generally remains under the soft tissue of the flipper, though digit reduction gradually occurs such as in baleen whales (mysticeti). Marine mammals evolving flippers represents a classic example of convergent evolution, and by some analyses, parallel evolution. Full webbing of the digits in the manus and/or pes is present in a number of aquatic tetrapods.
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The skeletal parts which form a structure used for swimming, such as a fin, would not be ideal to form a wing, which is better-suited for flight. One explanation for the forelimbs' similar composition is descent with modification. Through random mutations and natural selection, each organism's anatomical structures gradually adapted to suit their respective habitats. The rules for development of special characteristics which differ significantly from general homology were listed by Karl Ernst von Baer as the laws now named after him.
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Brachiating primates have long forelimbs and curved fingers Brachiation (from "brachium", Latin for "arm"), or arm swinging, is a form of arboreal locomotion in which primates swing from tree limb to tree limb using only their arms. During brachiation, the body is alternately supported under each forelimb. This form of locomotion is the primary means of locomotion for the small gibbons and siamangs of southeast Asia. Gibbons in particular use brachiation for as much as 80% of their locomotor activities.
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Meanwhile, the transverse processes of the dorsals are characteristically long and pronounced, terminating in sub-circular facet joints for the rounded heads of the ribs. Also like Tanystropheus, the transverse processes of the tail become gradually reduced alongside the forward processes of the chevrons, disappearing by the 35th caudal vertebra. Like Tanystropheus and Macrocnemus, the scapula is low. The long bones of the forelimbs have expanded and robust top ends; the deltopectoral crest on the humerus is also rather prominent.
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In addition, Matt Martyniuk has noted that the hypothesis that wing feathers evolved as early as allosauroids is not as unlikely as Cau claimed. Cau used examples of wingless feathered dinosaurs such as Dilong and compsognathids to support the idea that wing feathers only involved within Paraves. However, Martyniuk noted that their absence in Dilong and compsognathids may have been an independent reversion correlated with the reduced forelimbs in those lineages, similar to the case with many modern flightless birds.
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Skull drawn by V. N. Lyakhov Dentition, as illustrated in Knight's Sketches in Natural History Skeleton The striped hyena has a fairly massive, but short torso set on long legs. The hind legs are significantly shorter than the forelimbs, thus causing the back to slope downwards. The legs are relatively thin and weak, with the forelegs being bent at the carpal region. The neck is thick, long and largely immobile, while the head is heavy and massive with a shortened facial region.
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It was a heavily built tyrannosaurid, and as a member of that group, it would have had small, two-fingered forelimbs, strong hindlimbs, and a very robust skull. The rear part of the skull of Lythronax appears to have been very broad, with eye sockets that faced forwards to a similar degree as seen in Tyrannosaurus. Lythronax had 11 tooth sockets in the of the upper jaw; most tyrannosaurids had more. The frontmost teeth were the largest, the longest being almost long.
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Giant anteater skeleton with visible "knuckle-walking" forelimbs All anteaters have elongated snouts equipped with a thin tongue that can be extended to a length greater than the length of the head; their tube-shaped mouths have lips but no teeth. They use their large, curved foreclaws to tear open ant and termite mounds and for defense, while their dense and long fur protects them from attacks from the insects. All species except the giant anteater have a long prehensile tail.
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When discovered, skin impressions probably encased the whole skeleton, but were partially destroyed while freeing it from the surrounding rocks. Skin impressions are preserved on the forelimbs, neck and throat, and the chest, as well as on the right side of the trunk. As well as the skin impressions, Sternberg noted the preservation of muscle impressions. In 2007, paleontologist Kenneth Carpenter suggested that even impressions of inner organs are possibly preserved; this cannot be evaluated without detailed computer tomography and x-ray analyses.
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The Pacific pocket mouse's diet consists of seeds, nuts, and green vegetation, when available.3 Mouse, Pacific pocket (Perognathus longimembris pacificus) These granivores will leave the burrow at night to gather the seeds, in order to avoid direct contact with the desert sun. Most of these seeds and vegetation can be found in bushes or small shrubbery close to the burrow. When seeds are not easily accessible, the mouse will use its forelimbs to dig holes in order to find resources.
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Phyllobates bicolor, also known as the black-legged poison frog, bicolored dart frog or neari in Choco, is the second-most toxic of the wild poison dart frogs. This species obtained its name due to its normally yellow or orange body with black or dark blue hindlegs and forelimbs below the elbow. It lives in the lowland forests in the Chocó area in western Colombia, along the San Juan River. In this species, the male transports tadpoles adhering on its back.
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In 1936 Charles Gilmore noted that previous reconstructions of Apatosaurus forelimbs erroneously proposed that the radius and ulna could cross; in life they would have remained parallel. Apatosaurus had a single large claw on each forelimb, a feature shared by all sauropods more derived than Shunosaurus. The first three toes had claws on each hindlimb. The phalangeal formula is 2-1-1-1-1, meaning the innermost finger (phalanx) on the forelimb has two bones and the next has one.
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The claws are deeply scooped on the underside to assist in digging in the ice of the natural habitat. Research of injury patterns in polar bear forelimbs found injuries to the right forelimb to be more frequent than those to the left, suggesting, perhaps, right-handedness. Unlike the brown bear, polar bears in captivity are rarely overweight or particularly large, possibly as a reaction to the warm conditions of most zoos. The 42 teeth of a polar bear reflect its highly carnivorous diet.
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C. gerrardii inhabits wet sclerophyll forests and rainforests as well as moist areas in woodlands. It shelters beneath leaf litter, in hollow logs, and in crevices of rocks and trees. Its slender body and limbs are an adaptation for moving in thick undergrowth. C. gerrardii moves with lateral undulations on smooth surfaces, but holds its hind limbs close to the body and moves its tail in a side-winding motion when moving through grass and when climbing on branches, using only the forelimbs.
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Linhevenator was assigned to the Troodontidae by the describers. It possesses a combination of "primitive" (basal) and derived characters, but was found to be a derived troodontid in a phylogenetic analysis, in a polytomy with Troodon and a clade formed by Zanabazar and Saurornithoides. This position was seen by the authors as an indication for an evolutionary trend in the Troodontidae of shortening the forelimbs and for a parallel evolution of large sickle-claws with both the troodontids and the dromaeosaurids.
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José Bonaparte also classified the South American Pisanosaurus as a heterodontosaurid at one time, but this animal is now known to be a more basal ornithischian. Skull of Abrictosaurus The membership of Heterodontosauridae is well-established in comparison to its uncertain phylogenetic position. Several early studies suggested that heterodontosaurids were very primitive ornithischians. Due to supposed similarities in the morphology of the forelimbs, Robert Bakker proposed a relationship between heterodontosaurids and early sauropodomorphs like Anchisaurus, bridging the orders Saurischia and Ornithischia.
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Breeding males have greatly swollen forelimbs and one large, pointed, black spine on the inner surface of the thumb and two black spines on each side of the chest. The dorsum is tan to reddish brown with broad, reddish brown marks on the body between the yellowish tan dorsolateral folds. The dorsal surfaces of the limbs are tan to reddish brown with narrow transverse brown bars. The upper lip is tan with a brown margin and dark brown triangular spots.
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Gobipteryx, along with other enantiornithes, is thought to have superprecocial development, in which it was capable of flying upon hatching. Evidence for this comes from the fact that the forelimbs and shoulders of advanced embryos are almost completely ossified. In addition, the growth of G. minuta has been shown to slow down immediately following hatching. This suggests that it was highly mobile in its life, since locomotion has been shown to slow the growth of young birds by focusing energy and resources elsewhere.
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This study hypothesizes a diet primarily consisting of meat.Fiorillo, Anthony R. (2008) "On the Occurrence of Exceptionally Large Teeth of Troodon (Dinosauria: Saurischia) from the Late Cretaceous of Northern Alaska" Palaios volume 23 pp.322-328 In 2011, another derived troodontid, Linhevenator, was described from Inner Mongolia, China. It was noted by the authors as having relatively short and robust forelimbs, along with an enlarged second pedal ungual akin to that of the dromaeosaurids, in comparison to more basal troodontids.
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The frogs' common name is derived from the small bronze-coloured strips that appear on either side of the lower jaw, between the snout and the posterior point of the forelimbs, within a week after metamorphosis.N. C. Hiragond and S. K. Saidapur (1999) Description of tadpoles of Rana temporalis from South India;Curr. Sc. 76(3), 442-446 The species has been referred to by several names, including Hylarana malabarica (incorrectly),Kelaart.Prod.Faun.Zeyl. I,p.192(1852) Rana flavascens,Journ.As.Soc.Beng. XXII,p.
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Restoration Giraffatitan was a sauropod, one of a group of four-legged, plant- eating dinosaurs with long necks and tails and relatively small brains. It had a giraffe-like build, with long forelimbs and a very long neck. The skull had a tall arch anterior to the eyes, consisting of the bony nares, a number of other openings, and "spatulate" teeth (resembling chisels). The first toe on its front foot and the first three toes on its hind feet were clawed.
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The snout is large and broadly rounded. The limbs are long and robust. The digits are well developed, and there is no appreciable webbing. The coloration is striking, with solid black background color and with bright pink to pinkish-cream dorsal spots: there is a pair of rounded spots on the back of the head, about the size of the eyeball in diameter, a small mid-dorsal spot in the neck, and a pair of large spots at the level of the forelimbs.
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The forelimbs were relatively long with a long hand. The first digit of the hand was completely absent including the first metacarpal; according to the describers this was not an accident of preservation but the actual condition of the living animal. The species would then not have possessed the thumb spike typical of its relatives. According to a cladistic analysis performed by the describers, Nanyangosaurus was a basal member of the Iguanodontia, more derived than Probactrosaurus and closely related to the Hadrosauroidea.
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Like other scansoriopterygids, the head was short and blunt-snouted, with a downturned lower jaw. Its few teeth were present only in the tips of the jaws, with the four upper front teeth per side being the largest and slightly forward-pointing, and the front lower teeth being angled even more strongly forward. The long, slender forelimbs were similar, overall, to those of most other paravian dinosaurs. Like other scansoriopterygid dinosaurs, the first finger was shortest and the third was the longest.
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Cristatusaurus is a genus of theropod dinosaur that lived during the Early Cretaceous Period of what is now Niger, 112 million years ago. It was a baryonychine member of the Spinosauridae, a group of large bipedal carnivores with well-built forelimbs and elongated, crocodile-like skulls. The type species Cristatusaurus lapparenti was named in 1998 by scientists Philippe Taquet and Dale Russell, on the basis of jaw bones and some vertebrae. Two claw fossils were also later assigned to Cristatusaurus.
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Thomas Henry Huxley (1825–1895) Scientific investigation into the origin of birds began shortly after the 1859 publication of Charles Darwin's On the Origin of Species. In 1860, a fossilized feather was discovered in Germany's Late Jurassic Solnhofen limestone. Christian Erich Hermann von Meyer described this feather as Archaeopteryx lithographica the next year. Richard Owen described a nearly complete skeleton in 1863, recognizing it as a bird despite many features reminiscent of reptiles, including clawed forelimbs and a long, bony tail.
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It has naked ears, which are black in colour with some times have a pale grey ring at their base. The dorsal fur is generally brown grizzled with grey except that the shoulders, flanks and outer forelimbs are rufous. It has greyish black palms on the hands and soles on the feet. The long tail, which is a fifth longer than the body, is bushy along its length and is coloured dark grey to black, and sometimes has a white tip.
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These were segments of the halfrings protecting the neck, with their typical low keels. The mount has the further peculiarity that it shows Talarurus as built like a hippopotamus, with a barrel-shaped thorax, not with the characteristic ankylosaurid low and wide body type, and the forelimbs are strongly splayed. This was caused by an incorrect positioning of the ribs as if they were appending instead of sticking out sideways; this mistake also prevented a mounting of the wide upper pelvic elements.
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The forelimbs are almost as long as the hindlimbs, but both pairs of legs are very short compared to the length of the trunk. The elements of the feet are enlarged, with elongated and slender digits. Distinct from other varanopids, the claws on Ascendonanus have a very strong curvature. The curved claws and the size and shape of the feet, including a longer fourth digit on the manus and on the pes, indicate Ascendonanus would have been a "clinging" climber rather than a "grasping" climber.
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There is little evidence that Paradipodinae dig permanent burrows. From observations, comb-toed jerboas only dig temporary burrows that do not branch, and the entrances are not sealed during the day, a behavior present in other jerboa species. Like the rest of the Dipodidae family, Paradipodinae is completely herbivorous, the diet consisting of fruits, shoots and other parts of a very selective range of desert plant species. The jerboas gather food by leaping into the shrubs from the ground or by climbing using their forelimbs and teeth.
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This tuco-tuco lives alone in an extensive burrow it digs. Soil is loosened with the forelimbs and pushed backwards by the hind limbs. There is usually a main passage with short side passages every few metres, one or more chambers for storing food and others for nesting. Most activity is in the morning with the animal expanding the tunnel to reach the roots and stems on which it feeds, and only emerging from the burrow briefly to gather nearby food before retreating again.
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Geomys arenarius is a medium sized rodent, with a relatively long and hairy tail, and pale coloration. Like other gophers, their bodies are thicker than other rodents, eyes are reduced, and they are equipped with large, strong-clawed forelimbs allowing them to be fossorial. Their fur is a dull brown along their backs, with scattered black tipped hairs. The dull brown coloration continues dorsally and laterally until it reaches the chest, abdomen and feet, where it sometimes blends with the white hair of these areas.
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Being a dicynodont, Lystrosaurus had only two teeth (a pair of tusk-like canines), and is thought to have had a horny beak that was used for biting off pieces of vegetation. Lystrosaurus was a heavily built, herbivorous animal, approximately the size of a pig. The structure of its shoulders and hip joints suggests that Lystrosaurus moved with a semi-sprawling gait. The forelimbs were even more robust than the hindlimbs, and the animal is thought to have been a powerful digger that nested in burrows.
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The Forrest's pika belongs to the pika family, Ochotonidae, which consists of small mammals that have short ears, forelimbs very slightly longer than hindlimbs, and no external tail. It was first described by the British zoologist Michael Rogers Oldfield Thomas in 1923, who gave it the scientific name Ochotona forresti. The taxonomy of the species is unclear. It was earlier assigned as a subspecies of the Moupin pika (Ochotona thibetana) by Feag and Kao in 1974, Weston in 1982, and Honacki, Kinman, and Koeppl in 1982.
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What had become walking limbs in cetaceans and seals evolved further, independently in a reverse form of convergent evolution, back to new forms of swimming fins. The forelimbs became flippers and the hind limbs became a tail terminating in two fins, called a fluke in the case of cetaceans.Felts WJL "Some functional and structural characteristics of cetacean flippers and flukes" Pages 255–275 in: Norris KS (ed.) Whales, Dolphins, and Porpoises, University of California Press. Fish tails are usually vertical and move from side to side.
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He vigorously collected specimens for his museum, "prepared or otherwise provided, mainly by the work of my own hands, and at my own expense". The specimens were arranged to enable students to compare the anatomy of different animals. He intended the comparative anatomy exhibits to demonstrate evolution through the presence of homologous structures. For example, in mammals, the arm and hand of a human, the wing of a bird, the foreleg of a horse, and the flipper of a whale are all homologous forelimbs.
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Like some other pachycephalosaurs, Prenocephale is known only from skulls and a few other small bones. For this reason, reconstructions usually depict Prenocephale as sharing the basic body plan common to all of the other Pachycephalosauria: a stout body with a short, thick neck, short forelimbs and tall hind legs. The head of Prenocephale was comparable to that of Stegoceras, albeit with closed supratemporal fenestrae. Also, the paired grooves above the supraorbitals/prefrontals (along with a posterior parietal that restricts the frontal dome) are absent in Prenocephale.
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This remnant is a large bony dermal shoulder girdle, comprising the plate-like interclavicle which was positioned on the midline of the chest, two clavicle bones on either side of it, and two boomerang-shaped cleithrum bones at the base of the neck. On the other hand, the bones of the endochondral shoulder girdle (i.e. the scapulae and coracoids), which supported the forelimbs, were lost along with the limbs. Adelospondyls possessed a large bony hyoid apparatus, including gill- supporting bones such as hypobranchials and ceratobranchials.
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To catch out-of-reach prey, the Komodo dragon may stand on its hind legs and use its tail as a support. As it matures, its claws are used primarily as weapons, as its great size makes climbing impractical. For shelter, the Komodo dragon digs holes that can measure from wide with its powerful forelimbs and claws. Because of its large size and habit of sleeping in these burrows, it is able to conserve body heat throughout the night and minimise its basking period the morning after.
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The posterior half of the skeleton was found in articulation and the anterior dorsal and cervical vertebrae and forelimbs were found partially disarticulated prior to burial. The skull was discovered slightly separated from the vertebral column. The skull and anterior presacrals were also exposed at the time of discovery and had been partially been destroyed by erosion. From the material known of the snout, only a small fragment of the right maxilla has been recovered and shows that the interdental plates are fused, but not striated.
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This length is measured along the curvature of the body so absolute length can differ between individuals. As calves, they gain an average of 1 kilogram per week. Amazonian manatees are large, cylindrically shaped mammals, with forelimbs modified into flippers, no free hind-limbs, and the rear of the body in the form of a flat, rounded, horizontal paddle. The flexible flippers are used for aiding motion over the bottom, scratching, touching and even embracing other manatees, and moving food into and cleaning the mouth.
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Chalicotherium (Ancient Greek /, -: pebble/gravel + /, diminutive of / : beast) is a genus of extinct odd-toed ungulates of the order Perissodactyla and family Chalicotheriidae, found in Europe, Africa, and Asia from the Late Oligocene to Early Pliocene, 28.4–3.6 million years ago, existing for approximately . This animal would look much like other chalicotheriid species: an odd-looking herbivore with long clawed forelimbs and stouter weight-bearing hindlimbs. The type species, Chalicotherium goldfussi, from Miocene and Pliocene Europe, was described by Johann Jakob Kaup in 1833.
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In equine anatomy, the term sesamoid bone usually refers to the two sesamoid bones found at the back of the fetlock or metacarpophalangeal and metatarsophalangeal joints in both hindlimbs and forelimbs. Strictly these should be termed the proximal sesamoid bones whereas the navicular bone should be referred to as the distal sesamoid bone. The patella is also a form of sesamoid bone in the horse. Although many carnivores have radial sesamoid bones, the giant panda and red panda independently evolved to have an enlarged radial sesamoid bone.
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Their proposed definition for the group was "the clade stemming from the first panavian with ... remiges and rectrices, that is, enlarged, stiff-shafted, closed-vaned (= barbules bearing hooked distal pennulae), pennaceous feathers arising from the distal forelimbs and tail".Gauthier, J. and de Queiroz, K. (2001). "Feathered dinosaurs, flying dinosaurs, crown dinosaurs, and the name 'Aves'". Pp. 7-41 in Gauthier, J. and L.F. Gall (eds.), New Perspectives on the Origin and Early Evolution of Birds: Proceedings of the International Symposium in Honor of John H. Ostrom.
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Simosaurus has well-developed vertebrae and a dorsoventrally flattened trunk that would have inhibited side- to-side movement. This movement, called lateral undulation, is seen in most other nothosaurs, including Nothosaurus. The humerus has well-developed crests and the underside of the pectoral girdle is large, suggesting that the forelimbs had a powerful downstroke and provided most of the thrust required for swimming. The scapula is relatively small for a reptile that swims with its limbs, indicating that the upstroke of Simosaurus was weak.
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Ambystoma bishopi is a medium-sized species with a snout to vent length of and 14 to 16 costal grooves. The head is long with a tapered snout and there are vomerine teeth in the roof of the mouth. The forelimbs are stout and the tail is flattened towards the tip, being shorter than the head and body length combined. The skin is smooth and the dorsal surface is reticulated, with thin grey lines forming a net-like pattern on a brownish-black background.
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The forelimbs were only half the length of the hindlimbs but quite powerful, as indicated by the broad upper end of the humerus that provided attachment areas for a large arm musculature. Like Plateosaurus, it had five digits on each hand and foot. The hand was short and wide, with a large sickle shaped thumb claw used for feeding or defense against predators. The thumb was the longest finger in the hand, while the fourth and fifth digits were tiny, giving the forepaws a lopsided look.
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Although its mass suggests a quadrupedal nature, Massospondylus would have been restricted to its hind legs for locomotion. Since the discovery of rudimentary and nonfunctional clavicles in ceratopsians, it was assumed that these shoulder bones were reduced in all dinosaurs that did not have true furculae. Robert Bakker (1987) suggested that this would have allowed the shoulder blades to swing with the forelimbs in quadrupedal dinosaurs, increasing their functional forelimb length. This would have reduced the discrepancy of length between fore- and hindlimbs in a quadrupedal Massospondylus.
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The hindlimbs are strongly reduced and does not articulate with the vertebral column which lack true sacral vertebrae. Basilosaurid forelimbs have broad and fan-shaped scapulae attached to a humerus, radius, and ulna which are flattened into a plane to which the elbow joint was restricted, effectively making pronation and supination impossible. Because of a shortage of forelimb fossils from other arachaocetes, it is not known if this arrangement is unique to basilosaurids. Some of the characteristics of basilosaurids are also present in Georgiacetus.
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This sense of smell is important in terms of marking territory as well as provide an indication of whether or not another lemur is a viable breeding partner. Lemurs are a diverse group of primates in terms of morphology and physiology. Some lemurs, such as the sportive lemurs and indriids, have longer hind limbs than forelimbs, making them excellent leapers. Indriids also have a specialized digestive system for folivory, exhibiting enlarged salivary glands, a spacious stomach, and an elongated caecum (lower gut) that facilitates fermentation.
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Models for Buitreraptor propose that it hunted by traveling large distances in pursuit of prey, which may explain the long-legged trait shared by various genera of Unenlagiidae. Buitreraptor is characterized by its long forelimbs and hands; it likely relied on them to restrain prey and the curved claw of the second pedal digit would have injured or killed the victim. Buitreraptor probably swallowed its prey whole due to its lack of serrated teeth with flesh-tearing capabilities; the teeth functioned to simply hold prey.
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The forelimbs and hind limbs have short black fur. The forefeet are large and digit 1 of the forefeet does not have a claw while digits 2-5 have a well developed claw.Jonathan Kingdon, David Happold, Thomas Butynski, Michael Hoffmann, Meredith Happold, Jan Kalina, , Mammals of Africa When the animal is threatened or excited, the mane erects and this strip parts, exposing the glandular area. The hairs in this area are, at the tips, like ordinary hair, but are otherwise spongy, fibrous, and absorbent.
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Thadeosaurus was a lizard-like animal, with a remarkably long tail that comprised about two thirds of the animal's total length of . It also had long toes, especially on the hind legs, which would have given it a powerful stride, since the toes would still touch the ground while the foot was being raised. Combined with a strong breast bone to increase the strength in the forelimbs, this means that Thadeosaurus was probably a good runner. Below is a cladogram from Reisz et al.
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St. George Dinosaur Discovery Site, Utah Welles envisioned Dilophosaurus as an active, clearly bipedal animal, similar to an enlarged ostrich. He found the forelimbs to have been powerful weapons, strong and flexible, and not used for locomotion. He noted that the hands were capable of grasping and slashing, of meeting each other, and reaching two- thirds up the neck. He proposed that in a sitting posture, the animal would rest on the large "foot" of its ischium, as well as its tail and feet.
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The caudate nucleus has been implicated in responses to visual beauty, and has been suggested as one of the "neural correlates of romantic love". Approach- attachment behavior and affect are also controlled by the caudate nucleus. Cats with bilateral removal of the caudate nuclei persistently approached and followed objects, attempting to contact the target, while exhibiting a friendly disposition by the elicitation of treading of the forelimbs and purring. The magnitude of the behavioral responses was correlated to the extent of the removal of the nuclei.
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Mammals are a diverse class of animals, mostly terrestrial but some are aquatic and others have evolved flapping or gliding flight. They mostly have four limbs but some aquatic mammals have no limbs or limbs modified into fins and the forelimbs of bats are modified into wings. The legs of most mammals are situated below the trunk, which is held well clear of the ground. The bones of mammals are well ossified and their teeth, which are usually differentiated, are coated in a layer of prismatic enamel.
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Further down the tail, the paramedian osteoderms become longer and finely pitted, while the lateral osteoderms shrink into triangular structures and then disappear. Small, keeled osteoderms were present on the limbs. Based on the flexed paramedian osteoderms, Jaxtasuchus likely had a more tall and narrow torso than Doswellia, which possessed six medial rows of osteoderms before flexure started to occur. Despite the heavy armor of the torso, the limb bones of Jaxtasuchus were fairly small and slender, with the hindlimbs longer than the forelimbs.
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The exact number of flight feathers cannot be determined from known specimens, however, as the preservation is too poor. The tails of several specimens preserve a fan of feathers (rectrices) at the tip, shorter than those on the forelimbs. The feather fan is similar to those of Microraptor and Caudipteryx, being restricted to the tip of the tail, unlike those of Archaeopteryx and Similicaudipteryx which have rectrices extending down much of the tail length. In at least one species, Jeholornis palmapenis, there were 11 tail feathers.
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Orohippus (Gr., "mountain horse") is an extinct equid that lived in the Eocene (about 50 million years ago). O. pumillus, AMNH It is believed to have evolved from equids such as Eohippus, as the earliest evidence for Orohippus appears about 2 million years after the first appearance of Eohippus. The anatomical differences between the two are slight: they were the same size, but Orohippus had a slimmer body, a more elongated head, slimmer forelimbs and longer hind legs, all of which are characteristics of a good jumper.
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Subadult The general tone of the fur is reddish, with the brightest hues occurring in winter. In the winter coat, the back is clothed in a saturated rusty-red to reddish colour with brownish highlights along the top of the head, neck and shoulders. The throat, chest, flanks, and belly and the upper parts of the limbs are less brightly coloured, and are more yellowish in tone. The lower parts of the limbs are whitish, with dark brownish bands on the anterior sides of the forelimbs.
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The individual and geographic variation observed in the southern tamandua have made the taxonomic description of these animals a difficult task. Animals from the southeastern part of the range are "strongly vested", meaning they have black markings from shoulder to rump; the black patch widens near the shoulders and encircles the forelimbs. The rest of the body can be blonde, tan, or brown. Animals from northern Brazil and Venezuela to west of the Andes are solid blonde, brown, or black, or are only lightly vested.
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It had very large forelimbs, with a wing-membrane distended by a long wing-finger, but the hindlimbs were very short. Until the 21st century, Istiodactylus was the only known pterosaur of its kind, and was placed in its own family, Istiodactylidae, within the group Ornithocheiroidea. Istiodactylus differed from other istiodactylids in having a proportionally shorter skull. The distinctive teeth of Istiodactylus indicate that it was a scavenger that may have used its teeth to sever morsels from large carcasses in the manner of a cookie cutter.
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Forelimbs are believed to be a physical feature that reflects the preferences and adaptations to a specific environment, indicating the environment a turtle would be most likely to reside in. Based on morphological data, Proganochelys is believed to have lived in a semi-aquatic environment. Turtles possessing short hands are believed to be most likely terrestrial, while turtles with long limbs are more likely to be aquatic. The majority of all testudines are short-handed and terrestrial, while all cheloniods are long-handed and aquatic.
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The sauropod fauna of the La Amarga Formation was diverse and included the basal rebbachisaurid Zapalasaurus, the dicraeosaurid Amargatitanis, and unnamed remains of basal titanosauriforms. The high diversity suggests that different sauropod species exploited different food sources in order to reduce competition. Basal Titanosauriforms showed proportionally longer necks, longer forelimbs, and broader tooth crowns than Dicraeosaurids and Rebbachisaurids, suggesting greater feeding heights. Amargasaurus probably fed above ground level at heights of up to , as evidenced by the anatomy of its neck and inner ear.
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Cetiosauriscus ( ) is a genus of sauropod dinosaur that lived between 166 and 164 million years ago during the Callovian (Middle Jurassic Period) in what is now England. A herbivore, Cetiosauriscus had—for sauropod standards—a moderately long tail, and longer forelimbs, making them as long as its hindlimbs. It has been estimated as about long and between in weight. The only known fossil that was later named Cetiosauriscus includes most of the rear half of a skeleton as well as a hindlimb (NHMUK R3078).
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Their propensity for unruly behavior exceeds that of captive skunks, and they are even less trustworthy when allowed to roam freely. Because of their intelligence and nimble forelimbs, even inexperienced raccoons are easily capable of unscrewing jars, uncorking bottles and opening door latches, with more experienced specimens having been recorded to open door knobs. Sexually mature raccoons often show aggressive natural behaviors such as biting during the mating season. Neutering them at around five or six months of age decreases the chances of aggressive behavior developing.
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Only the snout tip, the neck base, the forelimbs and the tail end are missing. Hundreds of osteoderms were found in connection with the skeleton, many more or less in their original position. From the 1960s onward, this fossil was further prepared by Ronald Croucher using acid baths to free the bones from the surrounding matrix, a method perfected for the Charmouth fossils. In 1992, Charig reported that only a single block had yet to be treated, but he died before the results could be published.
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Xenarthrans share several characteristics not present in other mammals. Authorities have tended to agree they are a primitive group of placental mammals not very closely related to other orders, without agreeing on how to classify them. George Gaylord Simpson first suggested in 1931 that their combination of unique characteristics shows the group evolved from highly specialized early ancestors that lived underground or were nocturnal and dug with their forelimbs to feed on social insects like ants or termites. Most researchers since then have agreed.
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Due to having heavy bones and a heavy body it is assumed that it rarely, if ever, flew. The thick walled tibiotarsus, constituting the thickest of all other extant and extinct Leptoptilini species, is an unusual feature for flying birds which usually selects for minimum mass. As well as heavier than normal bone structure, measured size ratios suggested that it may have had reduced forelimbs and therefore flight capabilities. The body size was similar in dimension to L. dubius, with the exception of its tibiotarsus.
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Petter's big- footed mouse is a terrestrial rodent with short forelimbs and long hindfeet.Goodman and Soarimalala, 2005, p. 454 With a head and body length of 150 mm (5.9 in) and body mass of 105 g (3.7 oz) in the only known complete specimen,Goodman and Soarimalala, 2006, table 1 it is much larger than M. bastardi, and its measurements fall at or above the upper end of the known range of variation in M. ingens. The upperparts are covered with soft and short, brown fur.
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The light is of lower intensity than the light produced by typical sonoluminescence and is not visible to the naked eye. It is most likely a by-product of the shock wave with no biological significance. However, it was the first known instance of an animal producing light by this effect. It has subsequently been discovered that another group of crustaceans, the mantis shrimp, contains species whose club-like forelimbs can strike so quickly and with such force as to induce sonoluminescent cavitation bubbles upon impact.
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The size of the holotype specimen is difficult to assess, as the two most characteristic elements of the skeleton, the skull and the humerus, are proportionally unusual. Estimating body size from the skull predicts a much larger humerus, and estimating it from the humerus predicts a much smaller skull. This may indicate that the skull was unusually large, the forelimbs were unusually small, or both. Roughly scaling from local crocodylomorph taxa such as Dromicosuchus and an undescribed species (specimen NCSM 21722), Zanno et al.
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LGP V002 is a partial skeleton including vertebrae of the back and tail, the shoulder girdle, and elements of the forelimbs and pelvis. LGP V003 is a partial skeleton containing a series of vertebrae including dorsals, sacrals and the first two caudals, and both ilia. LGP V004 consists of a front neck vertebra, a front back vertebra and a right shinbone of a small individual. LGP V005 is a partial skeleton containing the sacrum, the pelvis and a series of twenty-five front and middle tail vertebrae.
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These adaptations may have been the result of a dietary change from terrestrial prey to fish. Unlike crocodiles, the post-cranial skeletons of baryonychine spinosaurids do not appear to have aquatic adaptations. Supplementary Information Sereno and colleagues proposed in 1998 that the large thumb-claw and robust forelimbs of spinosaurids evolved in the Middle Jurassic, before the elongation of the skull and other adaptations related to fish-eating, since the former features are shared with their megalosaurid relatives. They also suggested that the spinosaurines and baryonychines diverged before the Barremian age of the Early Cretaceous.
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Analysis of the fossil at the University of Cape Town, South Africa reveals that the specimen was a fully grown adult, approximately long and estimated to weigh , roughly the size of a turkey. These dimensions make Changyuraptor the largest four-winged microraptorine known, exceeding previously known specimens in size by at least 60%. Like other microraptorines, Changyuraptor had feathers all over its body, including forelimbs and hindlimbs, which gives the appearance of having two pairs of wings. The presence of long feathers on all four limbs also suggests that these dinosaurs could fly.
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Limb and girdle remains The forelimbs of Mierasaurus exhibit many shared (synapomorphic) turiasaurian traits. In the shoulder girdle of Mierasaurus, the articulation with the scapula on the coracoid is about half the bone's length. The humerus is slender, with an HRI (humerus robustness index) of only 0.27; the maximum width of the bottom end, similarly, measures only 40% of the bone's total length. A T-shaped/Y-shaped profile is present at the top end of the ulna due to the strong development of the rear-projecting process.
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Taxidermied specimen at Melbourne Museum A genus of Peramelemorphia order of marsupials, allied by a monophyletic family, and regarded as exceptional in their morphology. The direct evidence of the two species is limited to twenty nine specimens remaining at museums in Australia and overseas. Their superficial appearance resembled the native bandicoots or kangaroo-rats, although very small and dainty, and comparable to the size of a young rabbit or kitten. The feet of forelimbs resemble those of the genus Sus and the hind legs seen as similar to a horse.
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The forelimbs strongly increased in robustness, while the hindlimbs did not become larger relative to the rest of the skeleton, indicating that the arms bore most of the weight. In the cervical halfrings, the underlying bone band developed outgrowths connecting it with the underlying osteoderms, which simultaneously fused to each other. On the skull, the caputegulae first ossified at the snout and the rear rim; gradually the ossification extended towards the middle regions. On the rest of the body, the ossification process progressed from the neck onwards in the direction of the tail.
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231 Finds of tail clubs of gigantic individuals suggest larger sizes but their reference to Saichania cannot be substantiated as the holotype, the only specimen sufficiently described, only consists of the front of the animal. Saichania shared the general ankylosaurid build, being a low-slung, broad, heavily armoured dinosaur, with short forelimbs. Even for an ankylosaurid however, Saichania is exceptionally robust, its rump strengthened by ossifications and fusions of the vertebral column, ribs, shoulder girdle and breast bones. Arbour in 2014 established a revised list of distinguishing traits.
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Fused neural spines and well-ossified joints indicate that the holotype specimen of Cabarzia was an adult animal. The curved claws of Cabarzia and Tambacarnifex were likely adapted for predation, in contrast to the more straight claws of Mesenosaurus and Varanops which may have been more useful for digging. The broad ulnare is an adaptation also seen in aquatic animals, although there is no other evidence for aquatic habits in Cabarzia. Cabarzia's proportions (short forelimbs, thin body, long hindlimbs and tail) are similar to those of modern lizards capable of bipedalism.
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Restoration of three Tropeognathus in flight, notice their high aspect ratio The forelimbs of ornithocheirids were proportionally enormous, around five times longer than their legs. Substantial anchorage on the body is required given the mighty arms, and accordingly, ornithocheirids have robust scapulocoracoids, and stout, deeply keeled sterna, which served the purpose of housing their substantial forelimb muscles. The shoulder or pectoral girdle in ornithocheirids is set at a perpendicular angle to the spine, with the coracoids being much longer than the scapulae. The shoulder girdle is also of typical construction for ornithocheiroids.
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While the forelimbs carry the weight the hind limbs provide propulsion, due to the angle between the stifle and hock. This angle allows the hind legs to flex as weight is applied during the stride, then release as a spring to create forward or upward movement. The propulsion is then transmitted to the forehand through the structures of the back, where the forehand then acts to control speed, balance and turning. The range of motion and propulsion power in horses varies significantly, based on the placement of muscle attachment to bone.
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All known forms of Frasnian tetrapods became extinct in the Late Devonian extinction, also known as the end-Frasnian extinction. This marked the beginning of a gap in the tetrapod fossil record known as the Famennian gap, occupying roughly the first half of the Famennian stage. The oldest near-complete tetrapod fossils, Acanthostega and Ichthyostega, date from the second half of the Fammennian. Although both were essentially four- footed fish, Ichthyostega is the earliest known tetrapod that may have had the ability to pull itself onto land and drag itself forward with its forelimbs.
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A rod-like clavicle bone was present along the front edge of each coracoid, and a narrow T-shaped interclavicle was placed between the two coracoids. Possible oval-shaped sternal plates were present behind the pectoral girdle. These plates are bony components of the sternum (breastplate), which in most reptiles is completely cartilaginous and in birds is completely bony. Each humerus (upper arm bone, the only portion of the forelimbs which is completely preserved) is narrow at the mid-shaft but has expanded proximal (near to the body) and distal (away from the body) ends.
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Differences in the post-cranial skeleton between Akidolestes cifellii and related taxa allow insights into ecological differentiation within early therian mammal evolution. Correlation between limb posture and locomotor function in Akidolestes cifellii indicates that the hypertrophied parafibular process on the fibula helped the flexed function of the knee joint. A short neck on the femur and asymmetrical condyles on the humerus indicate a horizontal orientation of the femur. Akidolestes probably had a parasagittal forelimb posture and most likely a semi-erect or sprawling posture for both forelimbs and hindlimbs.
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It is known from a nearly complete holotype skeleton as well as a referred skull. The holotype skeleton had an estimated length of 1.2 meters (4 feet), while the referred skull was 17% larger than that of the holotype. Trucidocynodon is considered one of the largest known carnivorous cynodonts from the Triassic, as well as one of the largest probainognathians in the entire Mesozoic. A biomechanical study has argued that Trucidocynodon not only had erect limbs, but that it also possibly had digitigrade forelimbs, being among the first synapsids to show adaptations for cursoriality.
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Fruitafossor, from the late Jurassic period about 150 million years ago, was about the size of a chipmunk, and its teeth, forelimbs and back suggest that it dug open the nests of social insects (probably termites, as ants had not yet appeared). The first multituberculates like Rugosodon evolved, while volaticotherians took to the skies. The Middle Jurassic spans from 175 to 163 million years ago. During this epoch, dinosaurs flourished as huge herds of sauropods, such as Brachiosaurus and Diplodocus, filled the fern prairies, chased by many new predators such as Allosaurus.
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A pillar-erect limb posture is one where the femur articulates vertically with the acetabulum of the hip, which is angled downward, so that the leg is positioned beneath the body and acts as a pillar bearing weight. While the limb posture is similar to rauisuchians, the feet resemble those of phytosaurs (crocodile-like semiaquatic crurotarsans) in the retention of primitive characteristics. Although the forelimbs are much smaller than the hind limbs, all aetosaurs were quadrupeds. Diagram showing aetosaur osteoderms with labeled terminology, based on the genus Neoaetosauroides.
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A sea-lion, illustrated in A Complete Guide to Heraldry (1909). In heraldry, the term sea-lion (sometimes called a morse) refers to a legendary creature that has the head and upper body of a lion, but with webbed forelimbs and a fish tail. These occur most frequently as supporters, but also occur as crests and occasionally as charges. Sea-lions are frequently found in "sejant" or "sejant-erect" (sitting upright) attitudes, but may also be found "naiant" (horizontally, as if swimming) or "assurgeant" (issuing from the waves of the sea).
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In beetles, the first pair of wings has evolved into a pair of hard wing covers, while in Dipteran flies the second pair of wings has evolved into small halteres used for balance. Similarly, the forelimbs of ancestral vertebrates have evolved into the front flippers of whales, the wings of birds, the running forelegs of dogs, deer, and horses, the short forelegs of frogs and lizards, and the grasping hands of primates including humans. The same major forearm bones (humerus, radius, and ulna) are found in fossils of lobe-finned fish such as Eusthenopteron.
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Currently, researchers classify gibbons and siamangs as the only true brachiators and classify the great apes as modified brachiators. All other brachiation behaviours that do not meet either of these classifications are referred to as forearm suspensory postures and locomotion. Some traits that allow primates to brachiate include a short spine (particularity the lumbar spine), short fingernails (instead of claws), long curved fingers, reduced thumbs, long forelimbs and freely rotating wrists. Modern humans retain many physical characteristics that suggest a brachiator ancestor, including flexible shoulder joints and fingers well-suited for grasping.
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The dugong is largely dependent on seagrass communities for subsistence and is thus restricted to the coastal habitats which support seagrass meadows, with the largest dugong concentrations typically occurring in wide, shallow, protected areas such as bays, mangrove channels, the waters of large inshore islands and inter-reefal waters. The northern waters of Australia between Shark Bay and Moreton Bay are believed to be the dugong's contemporary stronghold. Like all modern sirenians, the dugong has a fusiform body with no dorsal fin or hind limbs. The forelimbs or flippers are paddle-like.
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The name mantid properly refers only to members of the family Mantidae, which was, historically, the only family in the order. The other common name, praying mantis, applied to any species in the order (though in Europe mainly to Mantis religiosa), comes from the typical "prayer-like" posture with folded forelimbs. The vernacular plural "mantises" (used in this article) was confined largely to the US, with "mantids" predominantly used as the plural in the UK and elsewhere, until the family Mantidae was further split in 2002.Bragg, P. E. (1996).
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The adult specimen of Epidexipteryx lacked preserved feathers around the forelimbs, but preserved simple feathers on the body and long, ribbon-like feathers on the tail. The tail feathers, likely used in display, consisted of a central shaft (rachis) and unbranched vane (unlike the vanes of modern feathers, which are broken up into smaller filaments or barbs). Yi also preserves feathers. These are notably very simple for a member of Pennaraptora (a clade of which scansoriopterygids are usually considered members), being "paintbrush-like", with long quill-like bases topped by sprays of thinner filaments.
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Elephant skeleton There is considerable variation in the scale and proportions of body and limb, as well as the nature of loading, during standing and locomotion both among and between quadrupeds and bipeds. The anterior-posterior body mass distribution varies considerably among mammalian quadrupeds, which affects limb loading. When standing, many terrestrial quadrupeds support more of their weight on their forelimbs rather than their hind limbs; however, the distribution of body mass and limb loading changes when they move. Humans have a lower-limb mass that is greater than their upper-limb mass.
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C. rhodesiensis was a lean, elongated species of theropod dinosaur with an S shaped neck, long hind limbs that resembled the legs of large birds such as the Secretarybird, shorter forelimbs with four digits on each hand unlike most later theropods, and a long tail. While still lean, it sported a more robust frame than other Coelophysoidea members. Its extremely bird-like body lead to C. rhodesiensis being one of the first dinosaurs to be portrayed with feathers, though there is no direct evidence that it actually had feathers.
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2008, argued that the thick pectoral girdle served for locomotion of the forelimbs. They noted that this does not, however, detract from the theory that Postosuchus could also walk bipedally. In 2013, a major study of the skeletal structure concluded that Postosuchus may have been an obligate biped based on evidence from the anatomy of the digits, vertebrae, and pelvis. The proportions of the limbs and weight-bearing sections of the spine were very similar to many theropod dinosaurs, nearly all of which are thought to have been strictly bipedal.
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Bones of the hand, as interpreted by Ruiz and colleagues (2011) The forelimbs were proportionally shorter than in any other large carnivorous dinosaurs, including Tyrannosaurus. The forearm was only a quarter the size of the upper arm. There were no carpalia in the hand, so that the metacarpals articulated directly with the forearm. The hand showed four basic digits, though apparently only the middle two of these ended in finger bones, while the fourth consisted of a single splint-like metacarpal that may have represented an external 'spur'.
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Among other findings, the study suggested that, in a resting position, the forelimbs would have hung from the shoulders with the humerus angled backward slightly, the elbow bent, and the claws facing medially (inwards). The shoulder of Acrocanthosaurus was limited in its range of motion compared to that of humans. The arm could not swing in a complete circle, but could retract (swing backward) 109° from the vertical, so that the humerus could actually be angled slightly upwards. Protraction (swinging forward) was limited to only 24° past the vertical.
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Likewise, the middle claw may have been permanently flexed, while the third claw, also the smallest, was able to both flex and extend.Mounted skeleton seen from aboveAfter determining the ranges of motion in the joints of the forelimb, the study went on to hypothesize about the predatory habits of Acrocanthosaurus. The forelimbs could not swing forward very far, unable even to scratch the animal's own neck. Therefore, they were not likely to have been used in the initial capture of prey and Acrocanthosaurus probably led with its mouth when hunting.
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Once the prey was trapped against the body, Acrocanthosaurus may have dispatched it with its jaws. Another possibility is that Acrocanthosaurus held its prey in its jaws, while repeatedly retracting its forelimbs, tearing large gashes with its claws. Other less probable theories have suggested the forelimb range of motion being able to grasp onto the side of a sauropod and clinging on to topple the sauropods of smaller stature, though this is unlikely due to Acrocanthosaurus having a rather robust leg structure compared to other similarly structured theropods.
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Their forelimbs were large and strongly built, and the ulna bone had a unique shape in members of the family Megaraptoridae, a subset of megaraptorans which excludes Fukuiraptor and Phuwiangvenator. The first two fingers were elongated, with massive curved claws, while the third finger was small. Megaraptoran skull material is very incomplete, but a juvenile Megaraptor described in 2014 preserved a portion of the snout, which was long and slender. Leg bones referred to megaraptorans were also quite slender and similar to those of coelurosaurs adapted for running.
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A species of Lerista, distinguished by a small and slight form, eyelids that are movable and a less distinct dark stripe at the midline of each side. The overall coloration is olive grey to brown at the upperside, perhaps displaying greenish or red-brown tones, and with two or four rows of dark dot markings extending along the back. The dark pattern begins near the ear and ends along the tail, sometimes displaying light dot or dash marks. The limbs are functional, although the forelimbs are short at than 6 millimetres.
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In 2007, American biologist Michael Habib revealed the result of a study by CAT-scan of the type specimen of Bennettazhia. The humerus, long, is uncrushed, which is uncommon for a pterosaur fossil and therefore offered a rare opportunity to investigate the bone structure. Apart from the thin bone wall, the humerus was filled with a spongy tissue consisting of trabeculae, very thin bone layers and struts, forming a light yet strong construction. Habib inferred that such strength would have allowed even very large pterosaurs to launch themselves from the ground using their forelimbs.
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For example, in 1974, Tattersall and Schwartz labeled Mesopropithecus as a sister group to sifakas. With the discovery of an associated skeleton of M. dolichobrachion near Ankarana in 1986, it became clear that Mesopropithecus shared distinct traits with sloth lemurs. Unlike the indriids, but like the sloth lemurs, they had elongated forelimbs and other adaptations for arboreal suspension (hanging in trees), linking them most closely to family Paleaeopropithecidae. A comparison of these morphological traits between the sloth lemurs and indriids suggest that Mesopropithecus was the first genus to diverge within the sloth lemur family.
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The forelimbs and hindlimbs strongly resembled each other. The humerus in the upper arm, and the femur in the upper leg, had become large flat bones, expanded at their outer ends. The elbow joints and the knee joints were no longer functional: the lower arm and the lower leg could not flex in relation to the upper limb elements, but formed a flat continuation of them. All outer bones had become flat supporting elements of the flippers, tightly connected to each other and hardly able to rotate, flex, extend or spread.
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Size compared to a human At the time Lythronax was announced, news sites reported size estimates of about in length and around in weight, based on comparisons to the much larger relative Tyrannosaurus; Loewen stated that it may have grown even larger. American paleontologist Gregory S. Paul gave a lower estimate of in length and a weight of only in 2016. Lythronax was a relatively robust tyrannosaurid. Like other members of the group, it would have possessed small, two-fingered forelimbs, large and strong hindlimbs, broad jaws, and a very robustly constructed skull.
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Since the human brain proficiently extracts information about objects and events from the sounds they produce, TUS, and mimicry of TUS, might have achieved an iconic function. The prevalence of sound symbolism in many extant languages supports this idea. Self-produced TUS activates multimodal brain processing (motor neurons, hearing, proprioception, touch, vision), and TUS stimulates primate audiovisual mirror neurons, which is likely to stimulate the development of association chains. Tool use and auditory gestures involve motor-processing of the forelimbs, which is associated with the evolution of vertebrate vocal communication.
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Glaurung schneideri is known from a slab and counterslab discovered in 2002 by fossil collector Thomas Schneider. It was found in Late Permian Kupferschiefer sediments near Mansfeld, Germany. Although the original specimen remains in Schneider's private collection, there are several casts in European museums, such as MBR 3610 (stored at the Museum fur Naturkunde in Berlin) and PIN 5392/1 (stored at the Paleontological Institute in Moscow). The specimen consists of a flattened skull as well as material from the pectoral girdle, forelimbs, vertebrae, and gliding structures (termed "patagial spurs").
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Basal members of Sauropodomorpha are often collectively termed prosauropods, although this is likely a paraphyletic group, the exact phylogeny of which has not been conclusively determined. True sauropods appear to have developed in the Upper Triassic, with trackways from a basal member known as the ichnogenus Tetrasauropus being dated to 210 million years ago.Rogers, et al. 2005. p. 23 At this point, the forelimbs had lengthened to at least 70% of the length of the hindlimbs and the animals moved from a facultatively bipedal to a quadrupedal posture.
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Flattened and leaf-shaped, these extended from behind the head along the column and reducing in size, ended at the tail. There is also evidence that osteoderms were present on the ventral region of the tail, as seen in Ticinosuchus ferox, and even on the flank, belly and limbs.Gower and Schoch (2009), p. 104. Like rauisuchians, Batrachotomus walked with an erect posture, although the limbs were not located directly under the trunk. The limbs were not equal in length as the forelimbs were about 70% of the hindlimbs.
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A European mole Moles are small mammals adapted to a subterranean lifestyle (i.e., fossorial). They have cylindrical bodies, velvety fur, very small, inconspicuous ears and eyes, reduced hindlimbs, and short, powerful forelimbs with large paws adapted for digging. The term mole is especially and most properly used for "true moles" of the family Talpidae in the order Eulipotyphla, which are found in most parts of North America, Europe and Asia, although it may also refer to unrelated mammals of Australia and southern Africa that have convergently evolved the "mole" body plan.
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The type specimen of Isisaurus colberti, ISI R 335/1-65, was originally described and named as Titanosaurus colberti by Sohan Lal Jain and Saswati Bandyopadhyay in 1997, the specific name honouring Edwin Harris Colbert, but was placed in its own genus, by Wilson and Upchurch, in 2003. It had a short, vertically directed neck and long forelimbs, making it considerably different from other sauropods. The humerus is 148 centimetres long. Based on this specimen, Isisaurus would have grown to about 18 meters (60 feet) in length and weighed about 14,000 kg (15 tons).
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Also, the third metacarpal in Tarbosaurus is proportionally shorter than in other tyrannosaurids; in other tyrannosaurids (like Albertosaurus and Daspletosaurus), the third metacarpal is often longer than the first metacarpal, while in the Tarbosaurus specimens studied by Holtz, the third metacarpal is shorter than the first. In contrast to the forelimbs, the three-toed hindlimbs were long and thick, supporting the body in a bipedal posture. The long, heavy tail served as a counterweight to the head and torso and placed the center of gravity over the hips.
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They tell the hungry cat that he is a lion and a bulldog his prey, leading to several painful encounters for the cat. Hubie and Bertie as designed by Jones are nearly identical rodents (Hubie, a rat and Bertie, a mouse) with long snouts, large ears, and big, black noses. The two are anthropomorphic, walking on their stubby hind legs and using their forelimbs as arms. They are primarily distinguished by their color: one is brown with a lighter-colored belly and face, while the other is gray.
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Tyrannosaurs have very stubby forelimbs, with only two visible fingers. Quintaglios, on the other hand, have longer, more well developed arms with dexterous five-fingered hands, (four fingers and an opposable digit) similar to a human, (unlike humans, though, most Quintaglios are left-handed). The fingers terminate in curved, retractable claws, which can be extended when the Quintaglio is threatened, (though they are capable of extending and retracting them at will). They are much smaller than a Tyrannosaur, although still large; an old adult Quintaglio standing about high.
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It was thought that heterodontosaurids actually did replace their teeth continually, though more slowly than in other reptiles, but CT scanning of skulls from juvenile and mature Heterodontosaurus shows no replacement teeth. There is currently no evidence that supports the hypothesis of aestivation in heterodontosaurids, but it cannot be rejected, based on the skull scans. While the cheek teeth of heterodontosaurids are clearly adapted for grinding tough plant material, their diet may have been omnivorous. The pointed premaxillary teeth and sharp, curved claws on the forelimbs suggest some degree of predatory behavior.
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The ilium of Limnoscelis possessed an iliac shelf, a low ridge extending anteroposteriorly across the dorsal ilium, a synapomorphy of the Diadectomorpha. The forelimbs and hindlimbs of Limnoscelis were short and robust, giving the animal a low sprawling posture. It had a phalangeal formula of 2-3-4-5-3 for the manus, and a formula of 2-3-4-5-4 for the pes, which it shared with basal amniotes. Originally, it was thought that Limnoscelis possessed two proximal tarsals, consisting of the fibulare and a preaxial element comprising a fused tibiale and intermedium.
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This lizard is generally a dull brown colour, but during the breeding season, the male turns bright blue, or sometimes just the head and throat turn blue with the other parts remaining brown. Females and juveniles are greyish-brown all year round, but females often have a crescent-shaped red patch on each side just behind the forelimbs. The scales on the dorsal surface are relatively small, uniformly overlapping, and slightly keeled. The mid-back scales are slightly larger than elsewhere, and the scales on the tail are larger than those on the back.
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Since the 1990s, dozens of feathered dinosaurs have been discovered in the clade Maniraptora, which includes the clade Avialae and the recent common ancestors of birds, Oviraptorosauria and Deinonychosauria. In 1998, the discovery of a feathered oviraptorosaurian, Caudipteryx zoui, challenged the notion of feathers as a structure exclusive to Avialae. Buried in the Yixian Formation in Liaoning, China, C. zoui lived during the Early Cretaceous Period. Present on the forelimbs and tails, their integumentary structure has been accepted as pennaceous vaned feathers based on the rachis and herringbone pattern of the barbs.
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By predating Archaeopteryx, Anchiornis proves the existence of a modernly feathered theropod ancestor, providing insight into the dinosaur-bird transition. The specimen shows distribution of large pennaceous feathers on the forelimbs and tail, implying that pennaceous feathers spread to the rest of the body at an earlier stage in theropod evolution. The development of pennaceous feathers did not replace earlier filamentous feathers. Filamentous feathers are preserved alongside modern-looking flight feathers — including some with modifications found in the feathers of extant diving birds — in 80 million year old amber from Alberta.
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Forty years later, this idea is almost universally accepted. Because of its extremely bird-like anatomy and close relationship to other dromaeosaurids, paleontologists hypothesize that Deinonychus was probably covered in feathers. Clear fossil evidence of modern avian-style feathers exists for several related dromaeosaurids, including Velociraptor and Microraptor, though no direct evidence is yet known for Deinonychus itself. When conducting studies of such areas as the range of motion in the forelimbs, paleontologists like Phil Senter have taken the likely presence of wing feathers (as present in all known dromaeosaurs with skin impressions) into consideration.
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Famously slow- moving, a sloth travels at an average speed of . Three-toed sloths are about the size of a small dog or a large cat, with the head and body having a combined length around and a weight of . Unlike the two-toed sloths, they also have short tails of , and they have three clawed toes on each limb. All sloths have three digits on their hindlimbs; the difference is found in the number of digits on the forelimbs; thus they are sometimes referred to as three-fingered sloths.
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Unlike other known spinosaurids, Ichthyovenator sail had a sinusoidal (wave-like) shape that curved downwards over the hips and divided into two separate sails. The pelvic girdle was reduced; the illium—the uppermost body of the pelvis—was proportionately longer than both the pubis and ischium than in other known theropod dinosaurs. Ichthyovenator was initially thought to belong to the subfamily Baryonychinae but more recent analyses place it as a primitive member of the Spinosaurinae. As a spinosaur, Ichthyovenator would have had a long, shallow snout and robust forelimbs.
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Majungasaurus is classified as a member of the theropod clade Abelisauridae, which is considered a family in Linnaean taxonomy. Along with the family Noasauridae, abelisaurids are included in the superfamily Abelisauroidea, which is in turn a subdivision of the infraorder Ceratosauria. Abelisaurids are known for their tall skulls with blunt snouts, extensive sculpturing on the outer surfaces of the facial bones (convergent with carcharodontosaurids), very reduced (atrophied) forelimbs (convergent with tyrannosaurids), and stocky hindlimb proportions, among other features. As with many dinosaur families, the systematics (evolutionary relationships) within the family Abelisauridae are confused.
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Lordosis behavior by a female cat during copulation Lordosis in hamsters Lordosis behavior, also known as mammalian lordosis (Greek lordōsis, from lordos "bent backward") or presenting, is the naturally occurring body posture for sexual receptivity to copulation present in most mammals including rodents, elephants, and cats. The primary characteristics of the behavior are a lowering of the forelimbs but with the rear limbs extended and hips raised, ventral arching of the spine and a raising, or sideward displacement, of the tail. During lordosis, the spine curves dorsoventrally so that its apex points towards the abdomen.
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Female mallard duck Tau emerald dragonfly Kea The only groups of living things that use powered flight are birds, insects, and bats, while many groups have evolved gliding. The extinct pterosaurs, an order of reptiles contemporaneous with the dinosaurs, were also very successful flying animals. Each of these groups' wings evolved independently. The wings of the flying vertebrate groups are all based on the forelimbs, but differ significantly in structure; those of insects are hypothesized to be highly modified versions of structures that form gills in most other groups of arthropods.
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Taxonomic classification of amphisbaenians was traditionally based on morphological characters, such as the number of preanal pores, body annuli, and tail annuli. Such characters are vulnerable to convergent evolution; in particular, the loss of the forelimbs and the evolution of specialized shovel-headed and keel-headed morphs appear to have occurred multiple times in the history of the group.Kearney, Maureen, and Bryan L. Stuart. "Repeated evolution of limblessness and digging heads in worm lizards revealed by DNA from old bones." Proceedings of the Royal Society of London B 271 (2004): 1677–1684.
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An increase in leg length since the evolution of bipedalism changed how leg muscles functioned in upright gait. In humans the "push" for walking comes from the leg muscles acting at the ankle. A longer leg allows the use of the natural swing of the limb so that, when walking, humans do not need to use muscle to swing the other leg forward for the next step. As a consequence, since the human forelimbs are not needed for locomotion, they are instead optimized for carrying, holding, and manipulating objects with great precision.
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It was a bulky quadruped that unlike other early archosauromorphs had a relatively short tail and robust limbs that were held in an odd mix of sprawled hind limbs and raised forelimbs. It had a long neck and a proportionately small head with remarkably sauropod-like jaws and teeth. Azendohsaurus used to be classified as a herbivorous dinosaur, at first as an ornithischian but more often as a "prosauropod" sauropodomorph. This was based only on its jaws and teeth, which share derived features typically found in herbivorous dinosaurs.
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Premaxilla of A. madagaskarensis with teeth The forelimbs and shoulders (pectoral girdle) of Azendohsaurus are well developed and robust. The scapula (shoulder blade) is long, about twice as tall as it is wide, matching the length and curvature of the ribs to accommodate the deep chest. The blade is concave on each side with a slightly expanded tip that is pointed at the back. The interclavicle is large and robust, and shares with Trilophosaurus and some rhynchosaurs a long "paddle-like" posterior process that is flattened and expanded towards the tip.
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Sereno stressed that the general build was gracile and that the forelimbs and the lower leg were relatively long: the humerus has length of forty centimetres and the tibia and fourth metatarsal measure 687 and 321 millimetres respectively, as compared to a thighbone length of seventy-six centimetres. Several autapomorphies have been established, traits that distinguish Afrovenator from its nearest relatives. The depression in which the antorbital fenestra is located, has a front end in the form of a lobe. The third neck vertebra has a low rectangular spine.
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In other animals, the term arm can also be used for analogous structures, (such as one of the paired forelimbs of a four-legged animal or the arms of cephalopods). In anatomical usage, the term arm may sometimes refer specifically to the segment between the shoulder and the elbow, while the segment between the elbow and wrist is the forearm. However, in common, literary, and historical usage, arm refers to the entire upper limb from shoulder to wrist. This article uses the former definition; see upper limb for the wider definition.
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Baryonyx was the first theropod dinosaur demonstrated to have been piscivorous (fish-eating), as evidenced by fish scales in the stomach region of the holotype specimen. It may also have been an active predator of larger prey and a scavenger, since it also contained bones of a juvenile iguanodontid. The creature would have caught and processed its prey primarily with its forelimbs and large claws. Baryonyx may have had semiaquatic habits, and coexisted with other theropod, ornithopod, and sauropod dinosaurs, as well as pterosaurs, crocodiles, turtles and fishes, in a fluvial environment.
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These adaptations may have been the result of a dietary change from terrestrial prey to fish. Unlike crocodiles, the post-cranial skeletons of baryonychine spinosaurids do not appear to have aquatic adaptations. Supplementary Information Sereno and colleagues proposed in 1998 that the large thumb-claw and robust forelimbs of spinosaurids evolved in the Middle Jurassic, before the elongation of the skull and other adaptations related to fish-eating, since the former features are shared with their megalosaurid relatives. They also suggested that the spinosaurines and baryonychines diverged before the Barremian age of the Early Cretaceous.
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Plastic model of a herd in the JuraPark in Solec Kujawski, Poland Vulcanodons limbs were sturdy and column-like, and its forelimbs were already proportionally long, reaching 76% of hindlimb length. Its lower leg, metatarsus, and toes were shortened in comparison to its bipedal ancestors, but still not as short as in later sauropods. The sacrum was made out of four fused sacral vertebrae; "prosauropods" possessed only three sacrals. The tail vertebra bodies already showed an incipient excavation of their lateral sides, saving weight and giving them a waisted appearance when viewed from below.
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Kofron (1999 and 2003) studied 241 documented cassowary attacks and found that one human and two dogs had been killed, but no evidence that cassowaries can disembowel or dismember other animals. Cassowaries use their claws to defend themselves, to attack threatening animals, and in agonistic displays such as the Bowed Threat Display. The seriema also has an enlarged second toe claw, and uses it to tear apart small prey items for swallowing. Phillip Manning and colleagues (2009) attempted to test the function of the sickle claw and similarly shaped claws on the forelimbs.
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The lower jaw was down-turned at the front and the teeth were distinct in having additional as well as third cutting edges in some of the hindmost teeth. The forelimbs were robust and had three fingers which bore large claws, and the feet had four toes supporting the foot—apart from therizinosaurs, all theropods had three-toed feet. The front of the pelvis was adapted to support the enlarged belly. The pubic bone was turned backwards, a feature that is only seen in birds and the dinosaurs most closely related to them.
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Microraptor had four wings, one on each of its forelimbs and hindlimbs, somewhat resembling one possible arrangement of the quartet of flight surfaces on a tandem wing aircraft of today. It had long pennaceous feathers on arms and hands with legs and feet . The long feathers on the legs of Microraptor were true flight feathers as seen in modern birds, with asymmetrical vanes on the arm, leg, and tail feathers. As in modern bird wings, Microraptor had both primary (anchored to the hand) and secondary (anchored to the arm) flight feathers.
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Shenzhousaurus is a genus of basal ornithomimosaur from the Lower Cretaceous of China. The holotype (NGMC 97-4-002, National Geological Museum of China) was collected from near the bottom (fluvial beds) of the Yixian Formation (Aptian) at the Sihetun fossil site, Beipiao, western Liaoning Province. This specimen consists of a partial skeleton preserved on a sandstone slab in a "death pose," its head above the torso. The distal parts of the hindlimbs, distal portion of the tail, and the forelimbs (except for part of the right hand) and the pectoral girdle are missing.
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If the prey senses the tiger's presence before this, the tiger usually abandons the hunt rather than chase prey or battle it head-on. Horizontal leaps of up to have been reported, although leaps of around half this distance are more typical. One in 2 to 20 hunts, including stalking near potential prey, ends in a successful kill. Bengal tiger attacking a sambar in Ranthambore Tiger Reserve When hunting larger animals, tigers prefer to bite the throat and use their powerful forelimbs to hold onto the prey, often simultaneously wrestling it to the ground.
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Large mature males can stand more than tall, with the largest confirmed one having been around tall and weighed . The red kangaroo maintains its internal temperature at a point of homeostasis about using a variety of physical, physiological, and behavioural adaptations. These include having an insulating layer of fur, being less active and staying in the shade when temperatures are high, panting, sweating, and licking its forelimbs. The red kangaroo's range of vision is approximately 300° (324° with about 25° overlap), due to the position of its eyes.
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Therizinosaurs (once called segnosaurs) were small to giant-sized, mainly herbivorous, theropod dinosaurs that have been found across the Early to Late Cretaceous deposits in Mongolia, China and North America. Various features of the forelimbs, skull and pelvis unite these finds as both theropods and maniraptorans, close relatives to birds. The representative genus, Therizinosaurus, is derived from the Greek θερίζω (therízo, meaning scythe, reap or cut) and σαῦρος (sauros, meaning lizard). The older representative, Segnosaurus, is derived from the Latin word segnis (meaning slow) and the Greek σαῦρος (sauros, meaning lizard).
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Reconstructed skeleton of Alxasaurus from China, the completeness of which confirmed therizinosaurs as theropods in 1993 In a 1990 review article, Barsbold and paleontologist Teresa Maryańska found Segnosauria to be a rare and aberrant group of saurischians, in an unresolved position among sauropodomorphs and theropods, probably closer to the former. They therefore listed them as Saurischia sedis mutabilis ("position subject to change"). Though they agreed the hindlimbs assigned to Therizinosaurus in 1982 were segnosaurian, they did not consider this justification for Therizinosaurus itself being a segnosaur, since it was only known from forelimbs.
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Fossils are found in a variety of rock formations dating to the Maastrichtian age of the upper Cretaceous period, 68 to 66 million years ago. It was the last known member of the tyrannosaurids, and among the last non-avian dinosaurs to exist before the Cretaceous–Paleogene extinction event. Like other tyrannosaurids, Tyrannosaurus was a bipedal carnivore with a massive skull balanced by a long, heavy tail. Relative to its large and powerful hind limbs, Tyrannosaurus forelimbs were short but unusually powerful for their size and had two clawed digits.
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Indiana University Press. p. 117. A terrestrial lifestyle is possible for the genus, as extreme differences in the size of the forelimbs relative to the hind limbs in comparison to other "thecodonts" may be considered a characteristic of bipedalism. However, this is most likely not the case for Chanaresuchus, and the evidence still remains in favor of a semiaquatic animal. The depositional environment of the locality from which specimens of Chanaresuchus have been found was in close proximity to an area of high volcanic activity, because it was in an active rift basin.
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Most statuary representations of griffins depict them with bird-like talons, although in some older illustrations griffins have a lion's forelimbs; they generally have a lion's hindquarters. Its eagle's head is conventionally given prominent ears; these are sometimes described as the lion's ears, but are often elongated (more like a horse's), and are sometimes feathered. Infrequently, a griffin is portrayed without wings, or a wingless eagle-headed lion is identified as a griffin. In 15th-century and later heraldry, such a beast may be called an alke or a keythong.
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Eurycea junaluska has a brownish dorsum with small dots or wavy lines along the body. An easy way to distinguish E. junaluska from E. bislineata is E. junaluska has a more robust body, longer forelimbs, and a shorter tail. Also, Sever and his colleagues studied the teeth series and discovered E. junaluska possesses a longer prevomerine teeth series. In addition to these traits, a wavy, broken, black stripe up to 0.80 mm wide extends from the nostril through the eye and through the sides of the body and tail.
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Older individuals tend to be uniformly dark brown or black. As with all dusky salamander species, both juveniles and adults have a pale single stripe outlined in black that extends from the eye and runs diagonally to the rear of the jaw. Additionally, both have 14 costal grooves, larger hind limbs than forelimbs, and a keeled (knife-like) tail that is triangular in cross-section and compressed laterally at the base. The tail is less than half its body length and is normally lighter in colour in comparison to the body.
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While their appearance may look odd for an ungulate with a horse-like head, similar forms have evolved repeatedly in unrelated lineages: large herbivores that feed as bipedal browsers, standing or sitting upright and pulling down branches or stripping vegetation with clawed forelimbs. Examples include therizinosaurs, the pantodont Barylambda, homalodotheres, and megatheriid ground sloths. Anisodon shows ischial callosities on the pelvis, a characteristic adaptation for sitting for long periods of time. Chalicotheriines are likely to have diverged as specialist feeders sitting in lush forests, similar to modern gorillas and giant pandas.
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The breastbone bore a strong keel for the attachment of flight muscles, and contained a distinct opening or fenestra, a unique characteristic of yanornithiformes. The upper and lower arm were about the same length. Like other ornithurines, Yixianornis had a highly fused hand, with many wrist bones joined together that are free in more primitive birds. The hips and hind limbs preserved more primitive features than the forelimbs, supporting the idea that the modern adaptations in the locomotion seen in modern birds evolved after the many specializations needed for flight.
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The Fontaine des Éléphants ("Elephants Fountain") is the most famous landmark in Chambéry. It was built in 1838 to honour Benoît de Boigne's feats when he was in India. The monumental fountain has strikingly realistic sculptures of the head and forelimbs of four lifesize elephants truncated into the base of a tall column in the shape of the savoyan (savoyarde) cross, topped by a statue of de Boigne. At first, the landmark was mocked by the local residents who were annoyed by it, but it now is accepted as one of the city's symbols.
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Reptilian lungs typically receive air via expansion and contraction of the ribs driven by axial muscles and buccal pumping. Crocodilians also rely on the hepatic piston method, in which the liver is pulled back by a muscle anchored to the pubic bone (part of the pelvis) called the diaphragmaticus, which in turn creates negative pressure in the crocodile's thoracic cavity, allowing air to be moved into the lungs by Boyle's law. Turtles, which are unable to move their ribs, instead use their forelimbs and pectoral girdle to force air in and out of the lungs.
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Like the two remaining species of the genus, the northern Onychogalea unguifera and rare O. fraenata (bridled nailtail), it had a horny spur at the tip of its tail. The species was compared to a hare or rabbit, in its habits, appearance and taste, and weighed around 3.5 kilograms. The species was extremely timid and would flee to a hollow log if disturbed at their daytime resting places, a small patch of sand cleared near a large shrub or tree. They ran with their short forelimbs awkwardly held toward the chest.
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Sauropods were herbivorous (plant-eating), usually quite long-necked quadrupeds (four-legged), often with spatulate (spatula-shaped: broad at the tip, narrow at the neck) teeth. They had tiny heads, massive bodies, and most had long tails. Their hind legs were thick, straight, and powerful, ending in club-like feet with five toes, though only the inner three (or in some cases four) bore claws. Their forelimbs were rather more slender and typically ended in pillar-like hands built for supporting weight; often only the thumb bore a claw.
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The flora during this time-period was dominated by seasonal small, fast-growing herbaceous plants, which stegosaurids could consume easily if Reichel's reconstruction is accurate. Mallison (2010) suggested that Kentrosaurus may have used a tripodal stance on their hindlimbs and tail to double the foraging height from the general low browsing height under one metre for stegosaurids. This challenged the view that stegosaurs are primarily low vegetation feeders because of their small heads, short necks and short forelimbs, since the tripodal stance would also give them access to young trees and high bushes.
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To take prey larger than themselves, the African wild dog, the dhole, and the gray wolf depend on their jaws as they cannot use their forelimbs to grapple with prey. They work together as a pack consisting of an alpha pair and their offspring from the current and previous years. Social mammal predators prey on herbivores with a body mass similar to that of the combined mass of the predator pack. The gray wolf specializes in preying on the vulnerable individuals of large prey, and a pack of timber wolves can bring down a moose.
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Sirrush bas-relief in the Pergamon Museum The mušḫuššu (; formerly also read as or ) or mushkhushshu ( or ), is a creature from ancient Mesopotamian mythology. A mythological hybrid, it is a scaly animal with hind legs resembling the talons of an eagle, lion-like forelimbs, a long neck and tail, a horned head, a snake-like tongue, and a crest. The most famously appears on the reconstructed Ishtar Gate of the city of Babylon, dating to the sixth century BCE. The form is the Akkadian nominative of , 'reddish snake', sometimes also translated as 'fierce snake'.
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Life restoration of two T. coccinarum Like all aetosaurs and many other early crurotarsans, Typothorax had erect hindlimbs held beneath the body. This is evident by a straight femur, an anteriorly directed pes (foot), and the projection of the lateral surface of the illium over the femur. Because the length of the femur is almost equal to that of the tibia and fibula (lower leg) and astragalus and calcaneum (ankle), Typothorax was probably slow-moving. The forelimbs are reduced in size and were directed outward in a sprawling position.
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The generic name means "like a crane" in Chinese. The specific name means "with slender wings". The holotype, JLUM-JZ07b1, was found in fluvial deposits of the lower Yixian Formation, which have a highest possible age of 139 million years and a lowest of 128 million years and thus date from some time in the early Valanginian to early Barremian stage. It consists of a partial skeleton, containing the skull, the lower jaws, a series of five cervical vertebrae, the shoulder girdle and the majority of both forelimbs and hindlimbs.
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Recovered vertebrae indicate a relatively short, wide, and deep thorax support the orthograde posture for climbing, clambering, and feeding in an arboreal environment. The longer forelimbs and dorsally situated scapulae provide a broad range of motion which would enable suspensory below-branch behavior and proficiency in reaching food during foraging.Susanna, I, Alba, D, Almécija, S, & Moyà-Solà, S 2014, 'The vertebral remains of the late Miocene great ape Hispanopithecus laietanus from Can Llobateres 2 (Vallès-Penedès Basin, NE Iberian Peninsula)', Journal of Human Evolution, 73, p. 15-34, Scopus, EBSCOhost, viewed 23 October 2014.
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Shoulder blade and coracoid of specimen AMNH 5895 Reconstructions of ankylosaur forelimb musculature made by Coombs in 1978 suggest that the forelimbs bore the majority of the animal's weight, and were adapted for high force delivery on the front feet, possibly for food gathering. In addition, Coombs suggested that ankylosaurs may have been capable diggers, though the hoof-like structure of the manus would have limited fossorial activity. Ankylosaurs were likely to have been slow-moving and sluggish animals, though they may have been capable of quick movements when necessary.
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Australovenator is based on a theropod specimen (AODF 604), affectionately nicknamed "Banjo" after Banjo Paterson, which was found intermingled with the remains of the sauropod Diamantinasaurus matildae at the "Matilda site" (AODL 85). The parts of the holotype as it was initially described, which are held at the Australian Age of Dinosaurs Museum of Natural History, consists of a left dentary, teeth, partial forelimbs and hindlimbs, a partial right ilium, ribs, and gastralia. Australovenator was described in 2009 by paleontologist Scott Hocknull of the Queensland Museum, and colleagues. The type species is A. wintonensis, in reference to nearby Winton.
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Donnellan, S., Eric, R.P., & Jennings, B. (2003). Systematics of the lizards family pygopidae with implications for the diversification of Australian temperate biotas. Systematic Biology, 52(6), 757-780. doi: 10.1080/10635150390250974 They have no forelimbs but have retained vestigial hind limbs in the form of small scaly flaps that are usually held flat on either side of the body Pygopods can further be distinguished from snakes by their broad fleshy tongues, ear-openings (which snakes lack) and their long tails, which grow up to four times the length of the body and can be voluntarily broken off.
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They are nocturnal omnivores that do not need to drink water, as they obtain their moisture from food, which includes insects and their larvae, seeds, spiders, bulbs, fruit, fungi, and very small animals. Most food is found by digging or scratching in the soil, and using their very long tongues. Unlike bandicoots, they are excellent burrowers and build extensive tunnel systems with their strong forelimbs and well-developed claws. A bilby typically makes a number of burrows within its home range, up to about a dozen, and moves between them, using them for shelter both from predators and the heat of the day.
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Lerista muelleri is a small terrestrial lizard typically reaching a maximum snout-to-vent length (SVL) of , and total adult length (including tail) reaching up to . A key distinguishing feature of the species is the presence of three digits on each of the forelimbs and hindlimbs. Scales are small, shiny, smooth textured and illustrate a tight pattern of composition. The head is elongated displaying a brown to black flecked pattern with recessed ears, and pointed snout providing evidence of adaptive fossorial behaviour. Colouration is reflective of habitat, with bodies’ commonly exhibiting brown, grey and bronze tones.
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The hand is quite distinct from other basal tetanurans, so it was not initially clear whether Megaraptor was an allosaurid, a carcharodontosaurid, a spinosauroid, or something else entirely. Subsequent studies, as well as the identification of close relatives with similar large claws on the forelimbs (see below), helped identify Megaraptor as a highly advanced and lightly built allosauroid, and a member of the family Neovenatoridae. More recent studies have proposed that Megaraptor and its kin are actually tyrannosauroids or spinosauroids as opposed to allosauroids. A juvenile specimen described in 2014 has provided more evidence towards Megaraptor being a primitive tyrannosauroid.
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The species had a body size of 23–26 cm and a 10–15 cm long tail. In form, they were almost bilby-like on first sight, having long, slender limbs, large, pointed ears, and a long tail. On closer examination, however, it became apparent that the pig-footed bandicoots were very unusual for marsupials. The forefeet had two functional toes with hooves, similar to the cloven hoof of a pig or deer; this is possibly due to juveniles being deposited in the pouch through external stalks, thus relieving them of using the forelimbs while as joeys.
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Cabarzia is an extinct genus of varanopid from the Early Permian of Germany. It contains only a single species, Cabarzia trostheidei, which is based on a well-preserved skeleton found in red beds of the Goldlauter Formation. Cabarzia shared many similarities with Mesenosaurus romeri (a varanopid from Russia), although it did retain some differences, such as more curved claws, a wide ulnare, and muscle scars on its sacral ribs. With long, slender hindlimbs, a narrow body, an elongated tail, and short, thick forelimbs, Cabarzia was likely capable of running bipedally to escape from predators, a behavior shared by some modern lizards.
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Mesozoic Meanderings 2 196 pp However, Dodson objected against this change, arguing the genitive singular might also refer to a single family name. In 1990 Thomas Lehman renamed A. lammersi into Monoclonius lammersi;Lehman, T.M., 1990, "The ceratopsian subfamily Chasmosaurinae: sexual dimorphism and systematics". In: K. Carpenter and P. J. Currie (eds.), Dinosaur Systematics: Perspectives and Approaches, Cambridge University Press, Cambridge pp 211-229 This alternative name has found no acceptance. The holotype, ANSP 15800, consists of a partial skeleton containing the lower skull, a left lower jaw, vertebrae, a complete shoulder girdle and most elements of forelimbs and hindlimbs.
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Tiktaalik also had a pattern of bones in the skull roof (upper half of the skull) that is similar to the end-Devonian tetrapod Ichthyostega. The two also shared a semi-rigid ribcage of overlapping ribs, which may have substituted for a rigid spine. In conjunction with robust forelimbs and shoulder girdle, both Tiktaalik and Ichthyostega may have had the ability to locomote on land in the manner of a seal, with the forward portion of the torso elevated, the hind part dragging behind. Finally, Tiktaalik fin bones are somewhat similar to the limb bones of tetrapods.
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The two puboischiadic plates on either side of the pelvis fuse at the bottom at an 80 degree angle in head-on view. The femur (thigh bone) was straight and rod-like, with a concave and bony head, although many details are unknown due to the bone being incomplete in all specimens. The tibia and fibula (lower leg bones) were also long, straight, and closely connected. As a whole the hindlimbs seemed to have been longer than the forelimbs, which may have allowed the animal to have been capable of running on two legs for part of the time.
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The pursuit of bulk plant matter is reflected in the stance, movement, and total bone structure of the ground sloth. In order to dislodge a large amount of foliage from the earth, L. armatus would have used its flat, spade-like phalanges in a hook-and-pull fashion to turn over soil and vegetation. Once again, the evolutionary design of the giant sloth favors quantity and force to quality and speed in its manus. While the giant sloth was not fully bipedal, its forelimbs show evolutionary pressure for specialized functions over walking and could easily shift its center of gravity.
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The olecranon of L. armatus, for example, is longer allometrically than species whose forelimbs are primarily adapted for movement; the longer olecranon on the ulna maximizes the leverage to the moment arm of the triceps, the extensor of the forearm, but is proportionally much longer than is necessary for walking (Bargo et al., 2000). The extension of the forearm would have been very strong, but not very fast. Triceps are the primary muscle activated during the digging motion, but the odd articulation of the scapula to the humerus, and therefore the orientation of the teres major, also strengthens the force during pulling.
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All species within this order have specialized forelimbs and a center of gravity shifted caudally towards the pelvis from other quadrupeds, but rostrally when compared to fully bipedal humans. The lumbar vertebrae are said to be xenarthrous, the eponymous characteristic of the magnorder, and that means that they come into contact with each other at more points to stabilize the pelvis and the bulk of the caudally shifted mass. It would have been unable to gallop. In humans, pelvic bones are not fused together in a solid block, and this allows us greater variability of motion from side to side.
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Although conceived by the film's creators as infantile, the creature is 25 stories tall (corresponding to 250+ feet or 76+ meters) and withstands missiles, artillery shells, and bombs with minimal injury. It is vaguely quadrupedal, though capable of standing upright over short distances. The limbs are comparatively long and thin compared with the body core, and according to creator Neville Page, this, coupled with its quadrupedal stance, is meant to imply that it is a newborn: he speculates that the adults may be bipedal. The forelimbs are large in proportion to the body, and the hind legs stubby.
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A specimen from the "hybrid zone" of the leaf green tree frog and southern leaf green tree frog showing physical characteristics of both species This is a fairly small species of tree frog, up to about 40 mm in length. It can be light green to dark olive green to light brown to dark brown on the dorsal surface. A pale golden stripe runs from the nostril, across the eye, over the typanum, and down the side, underlined by a dark brown stripe, which also goes over the typanum, not across it. The forelimbs, groin, and thighs are dark red.
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In this new paper they also described the new Erlikosaurus and Enigmosaurus (then unnamed) noting that segnosaurs were more similar to theropod dinosaurs and though some of their features resembled those of ornithischians and sauropods, these similarities were superficial and distinct when examined in detail. In 1982, Perle described a third specimen of the therizinosaurids Therizinosaurus. He referred this material to the genus based on the striking similarities with the specimens of Segnosaurus. Additionally, Perle acompared the forelimbs in these two taxa and concluded that they were characterized by elongated arms, possibly belonging to a single taxonomic group.
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While these belly scales were made of bone, scales on other parts of the body had less bone structure and were probably made of keratin instead. The scales on the sides of the body were flatter and smaller than the bony belly scutes. The scutes on the back of the body were similar, although more rounded in shape, with a few larger scutes near the midline. The scales of the hind limbs and the underside of the hip region were similar to those of the back, although no integument was preserved on the forelimbs or tail.
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Post-cranially, pliopithecoids had an interesting mix of platyrrhine and catarrhine traits. The brachial index of P. vindobonesis (the length of the radius divided by the length of the humerus) is similar to that of a howler monkey, but the crural index (the length of the tibia divided by the length of the femur) is similar to that of a gibbon. Proportionally, however, the forelimbs of P. vindobonesis were shorter than their hindlimbs, making them comparable to a baboon. The hands and feet of P. vindobonesis were long and curved, suggesting that pliopithecoids were adept and agile climbers.
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Reconstruction of Halszkaraptor escuilliei, with plumage and swimming posture based on aquatic birds that use wing-propelled swimming Halszkaraptor had characteristics that allowed it to spend time both in water and on land, including strong hindlimbs for running and smaller flipper-like forelimbs for swimming. The short tail would have brought the centre of gravity more to the front, which is more useful for swimming than walking. The torso would have been held more vertical than is normal with theropods. To this end, there are adaptations for an improved extension of the hindlimb, in the hip joint and the thighbone.
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Besides examples in which the horse-like forelimbs have been replaced by wings, there are other examples where the forelegs have several clawed digits (somewhat like lions), as in one relief at the Glyptothek in Munich, Germany. A Triton with a lower extremity like a lobster or crayfish, in a fresco unearthed from Herculanum has been mentioned. Double-tailed tritons began to be depicted by the late 2nd century BC, such as in the Altar of Domitius Ahenobarbus. Rumpf thought that might be the earliest example of a "Triton with two fish-tails (Triton mit zwei Fischschwänzen)".
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Functionally similar features that have arisen through convergent evolution are analogous, whereas homologous structures or traits have a common origin but can have dissimilar functions. Bird, bat, and pterosaur wings are analogous structures, but their forelimbs are homologous, sharing an ancestral state despite serving different functions. The opposite of convergence is divergent evolution, where related species evolve different traits. Convergent evolution is similar to parallel evolution, which occurs when two independent species evolve in the same direction and thus independently acquire similar characteristics; for instance, gliding frogs have evolved in parallel from multiple types of tree frog.
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Like the closely related Pteranodon, Nyctosaurus also had relatively long forelimbs compared to other earlier genera. Most of the tendons of the upper arm and forearm were mineralized within, this is a unique feature only seen in nyctosaurids, another of which was the related Muzquizopteryx. Another distinctive feature seen in Nyctosaurus was that it only had three phalanges instead of four, as seen in other pterodactyloids, this trait is rarely seen in other pterosaurs, and perhaps may have been an autapomorphy only found in Nyctosaurus. Nyctosaurus had unusually elongated metacarpals which measured about 2.5 times the length of its humerus.
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A baby kangaroo (joey) Kangaroos have developed a number of adaptations to a dry, infertile country and highly variable climate. As with all marsupials, the young are born at a very early stage of development—after a gestation of 31–36 days. At this stage, only the forelimbs are somewhat developed, to allow the newborn to climb to the pouch and attach to a teat. In comparison, a human embryo at a similar stage of development would be about seven weeks old, and premature babies born at less than 23 weeks are usually not mature enough to survive.
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As with other glyptodonts and xenarthrans, the center of mass appears to have been closer to the hind limbs than the forelimbs, indicating the vast majority and in some instance nearly all of the weight was borne on the hind limbs. This might show that glyptodonts, when their weight was displaced farther tailwards, could stand on two legs, though not necessarily maintaining an erect posture. Modern xenarthrans commonly stand up in this fashion for defense, to observe, or to feed. Strong hind limbs would also have been important while accelerating the tail club and maintaining posture after getting hit.
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Indeed, some humans even still develop vestigial vibrissal muscles in the upper lip. Thus, it is possible that the development of the whisker sensory system played an important role in mammalian development, more generally. Like monotremes today, the legs of early mammaliaforms were somewhat sprawling, giving a rather "reptilian" type of gait. However, there was a general tendency to have more erect forelimbs, forms like eutriconodonts even having a fundamentally modern forelimb anatomy while the hindlimbs remained "primitive"; this tendency is in some effect still seen in modern therian mammals, which often have more sprawling hindlimbs.
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Joeys have a continuous arch of cartilage in their shoulder girdle which disappears soon after birth; this supports the forelimbs, assisting the climb into the pouch. Young are completely contained in the pouch for 60 days after birth, wherein mammae provide nourishment during the remainder of development. Eyes first open around 80 days after birth, and young will leave the nest around 110 days after birth. By the time young are weaned, the thermoregulatory system is developed, and in conjunction with a large body size and thicker fur, they are able to regulate their own body temperature.
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Amphicoelias (, meaning "biconcave", from the Greek ἀμφί, amphi: "on both sides", and κοῖλος, koilos: "hollow, concave") is a genus of herbivorous sauropod dinosaur that lived approximately 150 million years ago during the Tithonian (Late Jurassic Period) of what is now Colorado, United States. An herbivore, Amphicoelias was moderately sized at about long–roughly the same length as Diplodocus, to which it was related. Its hindlimbs were very long and thin, and its forelimbs were proportionally longer than in relatives. The namesake fossil of the type species Amphicoelias altus, American Museum of Natural History 5764, is uncertain in included material.
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The Crows also believe that thunder birds can be distinguished from eagles in that they only had two claws on their feet. This may be derived from observations of the isolated remains of the two-fingered forelimbs left by tyrannosaurids such as Tyrannosaurus rex, which could be mistaken for the limb of a large unknown kind of bird. The Triceratops and Tyrannosaurus fossils of Montana's Hell Creek Formation may have influenced Cheyenne beliefs in monsters called ahk. When the Sioux lived around the Great Lakes, they imagined their mythical Water Monster Unktehi as a large aquatic buffalo-like mammal.
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Cats sometimes repeatedly tread their front paws on humans or soft objects with a kneading action. This is instinctive to kittens and adults, and is presumably derived from the action used to stimulate milk let-down by the mother during nursing. Kittens "knead" the breast while suckling, using the forelimbs one at a time in an alternating pattern to push against the mammary glands to stimulate lactation in the mother. Kneading may also have an origin going back to cats' wild ancestors who had to tread down grass or foliage to make a temporary nest in which to rest.
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The modern cetacean ear is highly specialised for hearing underwater and detecting certain frequencies, and Ambulocetus seems to share some of these traits. It is unclear if it used its specialised ear for hearing underwater, bone conduction on land, or if the adaptations were entirely non- functional in less aquatic cetaceans. Ambulocetus had a narrow, streamlined body, and heavy, pachyostotic ribs. Ambulocetus is thought to have swum much like modern river otters, alternating beats of the hind limbs while keeping the forelimbs tucked in for most of its propulsive power, as well as undulating the torso and tail.
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While these belly scales were made of bone, scales on other parts of the body had less bone structure and were probably made of keratin instead. The scales on the sides of the body were flatter and smaller than the bony belly scutes. The scutes on the back of the body were similar, although more rounded in shape, with a few larger scutes near the midline. The scales of the hind limbs and the underside of the hip region were similar to those of the back, although no integument was preserved on the forelimbs or tail.
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The teeth are very large, especially the canines, and the bite force is high relative to its body size for reasons not well understood; a possible explanation could be its frequent opening of tropical hardwood trees with its powerful jaws and claws in pursuit of insects, larvae, or honey. The head is large, broad and heavy in proportion to the body, but the ears are proportionately smaller; the palate is wide in proportion to the skull. The overall unique morphology of this bear—inward-turned front feet, flattened chest, powerful forelimbs with large claws—indicates adaptations for extensive climbing.
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In 2003, Adam Yates named the new species Thecodontosaurus caducus for a skull and a skull, a partial jawbone, and vertebrae of the cervix, an incomplete right pelvic bone, and partial forelimbs of an immature sauropodomorph. This material had been known in the scientific literature since 1984, and had been used to represent the genus Thecodontosaurus. However, changed understanding of the relationships and characteristics of basal sauropodomorphs (also known as prosauropods) has led Peter Galton, Yates, and D. Kermack to give T. caducus its own genus. The genus was named after the Pant-y-ffynnon quarry where it was discovered.
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During the examination, it turns out to be a highly specialized arthropod new to science. Upon further examination, they find that it has unique characteristics, such as an internalized exoskeleton, a strong, ridged tail to help it leap, and long, sharp teeth and mantis-like forelimbs as well as a second brain with functioning eyes in its hips. As they dissect further, the specimen is revealed to have been pregnant, and babies emerge from the corpse to feed on the deceased parent. Otto provokes one of the babies and is attacked by the juvenile Henders Rat, splitting his thumb.
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After some time, the animal stood up and moved forwards, with the left foot first, and once fully erect, it walked across the rest of the exposed surface, while leaving thin drag marks with the end of the tail. Crouching is a rarely captured behavior of theropods, and SGDS 18.T1 is the only such track with unambiguous impressions of theropod hands, which provides valuable information about how they used their forelimbs. The crouching posture was found to be very similar to that of modern birds, and shows that early theropods held the palms of their hands facing medially, towards each other.
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The hind limbs were longer than the forelimbs, the pelvis was dog-like in form and structure, and some specialized traits were present in the vertebrae. It had retractable claws, agile joints for climbing, and binocular vision. Miacis and related forms had brains that were relatively larger than those of the creodonts, and the larger brain size as compared with body size probably reflects an increase in intelligence. Like many other early carnivoramorphans, it was well suited for an arboreal climbing lifestyle with needle sharp claws, and had limbs and joints that resemble those of modern carnivorans.
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Traditionally a piscivorous lifestyle is attributed to Campylognathoides, as to most pterosaurs; in this case supported by the provenance of the finds from marine sediments and the very long wings. Pterosaurologist Kevin Padian, however, has suggested that, in view of the stout short teeth, ideal for delivering a piercing bite, the form might have been a predator of small terrestrial animals instead.Padian (2009), p. 105 Conversely, Mark Witton suggests the construction of Campylognathoides' extremely robust forelimbs, with proportionally long wing fingers, could be a specialization for a fast aerial lifestyle comparable to those of falcons and mastiff bats.
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Mesopropithecus and its closest sloth lemur relative, Babakotia, did share a few ancestral traits with indriids, unlike the largest sloth lemurs, Palaeopropithecus and Archaeoindris. These include the aforementioned four- toothed toothcomb, an inflated auditory bulla (bony structure that encloses part of the middle and inner ear), and an intrabullar ectotympanic ring (bony ring that holds the eardrum). While the skull of Mesopropithecus most closely resembles that of modern sifakas, the postcranial skeleton is quite different. Rather than having elongated hindlimbs for leaping, Mesopropithecus had elongated forelimbs, suggesting they predominantly used quadrupedal locomotion, slow climbing, with some forelimb and hindlimb suspension.
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More directed blows would have resulted in the sides of the spikes fracturing even sturdy longbones of the legs by blunt trauma. These attacks would have crippled small and medium-sized theropods and may even have done some damage to large ones. Earlier interpretations of the defensive behaviour of Kentrosaurus included the suggestion that the animal might have charged to the rear, to run through attackers with its spines, in the way of modern porcupines. Though Kentrosaurus likely stood with forelimbs erect like in other dinosaurs, it is hypothesised that the animal adopted a sprawling posture when defending itself.
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Between the first canine and the fifth postcanine tooth, the maxilla (main upper jaw bone) became thicker and formed bony supports divided by deep furrows between each tooth, which would have helped the animal's dentition precisely interlock when it closed its jaws. Ankylorhiza's sharp-tipped teeth had carinae (cutting edges) on both edges that bore occasional serrations, and its tooth enamel was adorned with lengthwise ridges. The lower incisors in the upper jaw were tusk-like and angled forwards. The morphology of Ankylorhiza's forelimbs was between that of basal (early-diverging or "primitive") and living cetaceans.
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It also had long ribs toward its backside that did not curve greatly. Liushusaurus may have been more similar in appearance to the living Chuckwalla (Sauromalus) of North America, which has a broad rather than flat body. Liushusaurus likely climbed on rough surfaces such as rocks and vegetation, aided by long, sharp claws, relatively symmetrical feet, long forelimbs, and well-developed scales on the undersides of its digits called tubercular plantar digital scales. The flattened body may have been useful in thermoregulation, providing a greater surface area for heat from the sun to reach while basking.
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All birds however have claws, which are used as general holdfasts and protection for the tip of the digits. The hoatzin and turaco are unique among extant birds in having functional claws on the thumb and index finger (digit I and II) on the forelimbs as chicks, allowing them to climb trees until the adult plumage with flight feathers develop. However, several birds have a claw- or nail-like structure hidden under the feathers at the end of the hand digits, notably ostriches, emus, ducks, geese and kiwis.Sir Walter Lawry Buller (1888): A History of the Birds of New Zealand.
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Galápagos tortoises possess two main shell forms that correlate with the biogeographic history of the species group. They exhibit a spectrum of carapace morphology ranging from "saddleback" (denoting upward arching of the front edge of the shell resembling a saddle) to "domed" (denoting a rounded convex surface resembling a dome). When a saddleback tortoise withdraws its head and forelimbs into its shell, a large unprotected gap remains over the neck, evidence of the lack of predation during the evolution of this structure. Larger islands with humid highlands over in elevation, such as Santa Cruz, have abundant vegetation near the ground.
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Confuciusornis shows a mix of basal and derived traits. It was more "advanced" or derived than Archaeopteryx in possessing a short tail with a pygostyle (a bone formed from a series of short, fused tail vertebrae) and a bony sternum (breastbone), but more basal or "primitive" than modern birds in retaining large claws on the forelimbs, having a primitive skull with a closed eye-socket, and a relatively small breastbone. At first the number of basal characteristics was exaggerated: Hou assumed in 1995 that a long tail was present and mistook grooves in the jaw bones for small degenerated teeth.
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Red-eyed tree frog (Agalychnis callidryas) with limbs and feet specialised for climbing The order Anura (from the Ancient Greek a(n)- meaning "without" and oura meaning "tail") comprises the frogs and toads. They usually have long hind limbs that fold underneath them, shorter forelimbs, webbed toes with no claws, no tails, large eyes and glandular moist skin. Members of this order with smooth skins are commonly referred to as frogs, while those with warty skins are known as toads. The difference is not a formal one taxonomically and there are numerous exceptions to this rule.
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Therefore, according to the International Code of Zoological Nomenclature (ICZN), the name Tyrannosaurus was used. Barnum Brown went on to collect several more tyrannosaurid specimens from Alberta, including the first to preserve the shortened, two-fingered forelimbs characteristic of the group (which Lawrence Lambe named Gorgosaurus libratus, "balanced fierce lizard", in 1914). A second significant find attributed to Gorgosaurus was made in 1942, in the form of a well-preserved, though unusually small, complete skull. The specimen waited until after the end of World War II to be studied by Charles W. Gilmore, who named it Gorgosaurus lancesnis.
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The snout and other parts of the skull also sported numerous foramina. According to the 2017 study which described D. horneri, scaly integument as well as tactile sensitivity was correlated with the multiple rows of neurovascular foramina seen in crocodylians and tyrannosaurids. The skull was perched at the end of a thick, S-shaped neck, and a long, heavy tail acted as a counterweight to balance out the head and torso, with the center of mass over the hips. Tyrannosaurids are known for their proportionately very small two-fingered forelimbs, although remnants of a vestigial third digit are sometimes found.
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Many bipedal dinosaurs possessed gracile leg bones with a short thigh relative to calf length. This is generally an adaptation to frequent sustained running, characteristic of endotherms which, unlike ectotherms, are capable of producing sufficient energy to stave off the onset of anaerobic metabolism in the muscle.Fastovsky & Weishampel 2009, p.252. Bakker and Ostrom both pointed out that all dinosaurs had erect hindlimbs and that all quadrupedal dinosaurs had erect forelimbs; and that among living animals only the endothermic ("warm-blooded") mammals and birds have erect limbs (Ostrom acknowledged that crocodilians' occasional "high walk" was a partial exception).
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It has a typical gopher-like body, with large, clawed, forelimbs, small eyes and ears, and a fur-lined cheek pouches. The fur is buff-brown fur and fades to white on the belly and feet. It is visually indistinguishable from the plains pocket gopher, and was formerly considered to be a subspecies of that animal, before being raised to full species status in 1989 on the basis of genetic differences. Knox Jones's pocket gopher is found in the central western regions of Texas, roughly between the counties of Ward, Martin, and Cochran, and in southeastern New Mexico as far as Chaves County.
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His original name was "Iguana-saurus" but he then received a letter from William Daniel Conybeare, "Your discovery of the analogy between the Iguana and the fossil teeth is very interesting but the name you propose will hardly do, because it is equally applicable to the recent iguana. Iguanoides or Iguanodon would be better." Mantell took this advice to heart and called his creature Iguanodon. Years later, Mantell had acquired enough fossil evidence to show that the dinosaur's forelimbs were much shorter than its hind legs, therefore proving they were not built like a mammal as claimed by Sir Richard Owen.
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Georges Cuvier originally described Palaeotherium as a kind of tapir, and as such, Palaeotherium was popularly reconstructed as a tapir-like animal. 19th and 20th century reconstructions, most famously those at Crystal Palace Park, depicted Palaeotherium with a short trunk like that seen in Tapirs. Reconstructions of this nature are now considered erroneous with Palaeotherium exhibiting a suite of distinct skeletal characteristics to Tapirs, such as more elongated legs, relatively long upright necks, and longer forelimbs than hindlimbs. Furthermore, although the nasal bones are set back, there is no specialization of the nasal area for proboscis like that observed in tapirs.
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Gorgosaurus ( ; meaning "dreadful lizard") is a genus of tyrannosaurid theropod dinosaur that lived in western North America during the Late Cretaceous Period (Campanian), between about 76.6 and 75.1 million years ago. Fossil remains have been found in the Canadian province of Alberta and possibly the U.S. state of Montana. Paleontologists recognize only the type species, G. libratus, although other species have been erroneously referred to the genus. Like most known tyrannosaurids, Gorgosaurus was a bipedal predator weighing more than two metric tons as an adult; dozens of large, sharp teeth lined its jaws, while its two-fingered forelimbs were comparatively small.
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Anchiornis was found to have black-and-white-patterned feathers on the forelimbs and hindlimbs, with a reddish-brown crest. This pattern is similar to the coloration of many extant bird species, which use plumage coloration for display and communication, including sexual selection and camouflage. It is likely that non-avian dinosaur species utilized plumage patterns for similar functions as modern birds before the origin of flight. In many cases, the physiological condition of the birds (especially males) is indicated by the quality of their feathers, and this is used (by the females) in mate choice.
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Although the name Majungasaurus crenatissimus was older than Majungatholus atopus, the authors judged the type dentary of Majungasaurus too fragmentary to confidently assign to the same species as the skull. Further fieldwork over the next decade turned up a series of less complete skulls, as well as dozens of partial skeletons of individuals ranging from juveniles to adults. Project members also collected hundreds of isolated bones and thousands of shed Majungasaurus teeth. Taken together, these remains represent nearly all the bones of the skeleton, although most of the forelimbs, most of the pelvis and the tip of the tail are still unknown.
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In contrast, virtually all locomotion functionality has been lost in humans while predominant brachiators, such as the gibbons, have very reduced thumbs and inflexible wrists. In ungulates the forelimbs are optimised to maximize speed and stamina to the extent that the limbs serve almost no other purpose. In contrast to the skeleton of human limbs, the proximal bones of ungulates are short and the distal bones long to provide length of stride; proximally, large and short muscles provide rapidity of step. The odd-toed ungulates, such as the horse, use a single third toe for weight-bearing and have significantly reduced metacarpals.
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Under natural conditions, sows will leave the herd and travel up to 6.5 km a day prior to parturition in order to find the appropriate spot for a nest. The sows will use their forelimbs and snouts in order to create excavated depressions within the ground and to gather/transport nesting materials. Although the nests vary in radius dependent on the age of the sow, the nests are generally a round to oval shape and are usually located near trees, uprooted stumps or logs. The shelter provided by the nest built in sows is of utmost importance to thermoregulation.
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The discovery of Eotyrannus corroborates the notion that early tyrannosauroids were gracile with long forelimbs and three-fingered grasping hands, although the somewhat large size of the animal either means that early evolution for this clade was carried out at a large size or Eotyrannus developed large size independently. The find of this animal in Europe puts in question to the purported Asian origin for these animals along with North American Stokesosaurus and European Aviatyrannis arguing for a more complex biogeography for tyrannosauroids. Below is a cladogram by Loewen et al. in 2013 that includes most tyrannosauroid genera.
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Its teeth had wrinkled enamel, similar to teeth from the related genus Baryonyx. As a spinosaur it would have had a long, low snout and robust forelimbs, and one possible skeleton indicates the presence of a tall sail running down its back, another typical trait of this theropod family. Siamosaurus is considered by some palaeontologists to be a dubious name, with some arguing that its teeth are hard to differentiate from those of other Early Cretaceous spinosaurids, and others that it may not be a dinosaur at all. Based on dental traits, Siamosaurus and "S." fusuiensis have been placed in the subfamily Spinosaurinae.
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Accordingly, they listed them as Saurischia sedis mutabilis (position subject to change). They agreed the hindlimbs assigned to Therizinosaurus in 1982 were segnosaurian but did not consider this a sufficient justification for Therizinosaurus itself being a segnosaur because it was only known from forelimbs. In 1993, Dale A. Russell and Dong Zhi-Ming described the new genus Alxasaurus from China; at the time this was the most complete large theropod from its time and place. While Alxasaurus was similar in some respects to prosauropods, the detailed morphology of its limbs linked it to Therizinosaurus and segnosaurs.
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Demodex canis Minor cases of demodectic mange usually do not cause much itching but might cause pustules, redness, scaling, leathery skin, hair loss, skin that is warm to the touch, or any combination of these. It most commonly appears first on the face, around the eyes, or at the corners of the mouth, and on the forelimbs and paws. It may be misdiagnosed as a "hot spot" or other skin ailment. In the more severe form, hair loss can occur in patches all over the body and might be accompanied by crusting, pain, enlarged lymph nodes, and deep skin infections.
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Smilodon is thought to have killed its prey by holding it still with its forelimbs and biting it, but it is unclear in what manner the bite itself was delivered. Scientists debate whether Smilodon had a social or a solitary lifestyle; analysis of modern predator behavior as well as of Smilodons fossil remains could be construed to lend support to either view. Smilodon probably lived in closed habitats such as forests and bush, which would have provided cover for ambushing prey. Smilodon died out at the same time that most North and South American megafauna disappeared, about 10,000 years ago.
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Dalianraptor (meaning "Dalian thief") is a genus of prehistoric bird that lived in China about 120 million years ago, during the early Cretaceous Period. It is very similar to the contemporary avialian Jeholornis, though it has a longer digit I (thumb-equivalent) and shorter forelimbs, which suggests it may have been flightless. Reaching about in length, it was found in Jiufotang Formation rocks in Liaoning Province. More recently, it is being suspected that the specimen is a chimera forged for the fossil trade, namely a Jeholornis with the arms exchanged by those of a flightless theropod.
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This meant they were robust and double-beamed, as in Diplodocus and its relatives like Mamenchisaurus. Because of the similarly "diplodociform" chevrons, Charig referred Cetiosauriscus to the Diplodocidae along with the new specimen. Elaborating upon his earlier paper, McIntosh (1990) weakly referred Cetiosauriscus to the subfamily Diplodocinae, characterised by more cervicals and fewer dorsals, tall sacrum neural spines, short forelimbs, no calcaneum, metatarsals III and IV being the longest, and a small process on the distal end of metatarsal I. The subfamily also included Diplodocus, Barosaurus and Apatosaurus. In 2004 this placement was followed by Weishampel et al.
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The specific name honours Fox. Fossils figured in Hulke, 1881 The holotype, BMNH R175, was found in a layer of the Upper Wessex Formation dating from the Barremian. It is an incomplete skeleton with the head, neck, anterior armour and forelimbs missing but including dorsal vertebrae, the sacrum, most of the pelvis, most of the left hindleg, the right thighbone, twenty-two tail vertebrae, ribs, chevrons, ossified tendons, a pelvic shield, twenty-two spikes and numerous ossicles. The skeleton was in 1881 studied by John Whitaker Hulke, while it was still in the possession of Fox.
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Although no skull bones of Albertonykus have been found, related animals from Mongolia show that they likely had long, slender snouts filled with tiny teeth similar to those of armadillos and anteaters. It is likely that Albertonykus ate insects, using its large thumb claw to tear open rotten logs to find its prey. As in other alvarezsaurs, the forelimbs of Albertonykus were specialized for digging, but were too short to permit burrowing. Unfortunately at this time the skeleton of Albertonykus is not complete, but its Mongolian relatives give us a distinct idea of what the rest of the skeleton would have looked like.
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Life restoration by Emily Willoughby The skeletal morphology of Serikornis suggests a terrestrial ecology without flying adaptations. The tail is covered proximally by filaments and distally by fine rectrices. Symmetrical, barbule- free remiges are attached along the forelimbs and elongated feathers of the hind limbs extend to the toes, suggesting that the remiges of the hind legs had evolved in the maniraptorans residing on the ground before being co-opted to an arboreal lifestyle and possibly, gliding. The coracoid of Serikornis is devoid of diagnostic ornamentation present in Anchiornis but is distinguished by having the tuberculous coracoid elongated to form a crest.
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The Horseshoe Canyon Formation is interpreted as having a significant marine influence, due to an encroaching Western Interior Seaway, the shallow sea that covered the midsection of North America through much of the Cretaceous. In life, Parksosaurus, as a hypsilophodont, would have been a small, swift bipedal herbivore. It would have had a moderately long neck and small head with a horny beak, short but strong forelimbs, and long powerful hindlimbs. Paul in 2010 suggested that the long toes were an adaptation for walking over mud or clay near rivers and that the strong arms were used for burrowing.
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Xenohyla is a genus of tree frogs in the family Hylidae that is endemic to xeric habitats of coastal Brazil, with Xenohyla eugenioi native to the State of Bahia and the State of Sergipe, and Xenohyla truncata native to the State of Rio de Janeiro. This genus is characterized by a robust body, wide flat head, short snout, short forelimbs with muscular forearms, and a truncate- shaped body when viewed from above. They are associated with bromeliads, where they hide during the day and eat the insects that also inhabit the plant. They breed in temporary pools that are formed by rainwater.
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The fur on the dorsal side of their body is dark at the roots, and fades to a light brown at the tips, which gives the bats a signature shiny, chestnut-brown appearance. Like all bats, the eastern small-footed bat has a patagium that connects the body to the forelimbs and tail, aiding in flight. Their head is relatively flat and short, with a forehead that slopes gradually away from the rostrum, a feature that is unique to other individuals in the Myotis species. They have erect ears, which are broad at the base and a short flat nose.
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A cat with the genetic deformity radial hypoplaisia or radial aplaysia while resting, showing twisted forelimbs A squitten is a cat with a genetic deformity which causes a partial formation or complete absence of the radius bone making it resemble a squirrel. These cats should be kept indoors and seen to by specialist veterinarians, as long term management of the condition is essential for quality of life in these cats.Kangaroo Cats and Squittens Revealed (October 2006) It is an example of a cat body type genetic mutation. The word is a portmanteau of squirrel and kitten.
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These different knobs are all somewhat continuous with each other, with no deep grooves separating each of them. The ulna and radius (lower arm bones) are also rather simple, although certain features (such as convex outermost joints) are shared with other archosauriforms. The manus (hand), although jumbled in GR 138 (the only specimen to preserve forelimbs), still possessed recognizable elements such as metacarpals (main hand bones) and short phalanges (finger bones). The innermost (first) and outermost (fifth) metacarpals, which would have connected to the thumb and little finger in humans, are the shortest parts of the hand.
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The Anglo-Irish naturalist Victor Brooke suggested in 1878 that deer could be bifurcated into two classes on the according to the features of the second and fifth metacarpal bones of their forelimbs: Plesiometacarpalia (most Old World deer) and Telemetacarpalia (most New World deer). He treated the musk deer as a cervid, placing it under Telemetacarpalia. While the telemetacarpal deer showed only those elements located far from the joint, the plesiometacarpal deer retained the elements closer to the joint as well. Differentiation on the basis of diploid number of chromosomes in the late 20th century has been flawed by several inconsistencies.
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Saga pedo is a species of bush cricket, spread throughout the European part of the Mediterranean, and Asia as far east as China. It is a wingless bush cricket, with the body size of up to , which makes it one of the largest European insects and one of the world's largest Orthoptera (grasshoppers, crickets and alike). Colloquially known as the predatory bush cricket, or the spiked magician (due to the "enchanting" manner in which it waves its forelimbs as it approaches its prey),Blondel, J., Aronson, J., Bodiou, J-Y. and Boeuf, G. (2010) The Mediterranean Region.
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The head and forelimbs found with Ixalerpeton are the first of these elements that have been found among lagerpetids. Unlike dinosauriforms, the posttemporal fenestra at the back of the skull is large and unreduced; there is an extra bone, the postfrontal, bordering the eye socket; there is no supratemporal fossa, which is an indentation found on the frontal bone in dinosauriforms; and the glenoid cavity on the scapula, where the scapula-humerus joint is located, faces slightly sideways instead of backwards. On the other hand, there is an anterior tympanic recess on the braincase, and the deltopectoral crest on the humerus is long, both of which are common among basal dinosauromorphs.
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The lower rear corner of the scapula (shoulder blade) was strongly ossified (built of strong bone), which suggests that movement of the scapula contributed to the stride length of the forelimbs and reduced the sideways flexing of the body. The five sacral vertebrae were massive but not fused to each other and to the pelvis, making the back more rigid and reducing sideways flexing while the animal was walking. Therapsids with fewer than five sacral vertebrae are thought to have had sprawling limbs, like those of modern lizards. In dinosaurs and mammals, which have erect limbs, the sacral vertebrae are fused to each other and to the pelvis.
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Tetrapod limb development involves many signaling molecules such as FGF, BMP, SHH and WNT. The apical ectodermal ridge is a structure found at the distal most tip which becomes a key signaling center for the developing limb. Surprisingly many of the same signaling pathways known to play a role in tetrapod limb development have been found to play a role in bat forelimb development but the timing, intensity, and spatial gene expression of some orthologous genes have changed. Since mice are also mammals, it is convenient to compare morphology and development of forelimbs between mice and bats; these comparisons may elucidate the genetic basis of adaptive bat wing development.
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It would have had large, robust forelimbs bearing three-fingered hands, with an enlarged claw on the first digit. The distinctive neural spines of Spinosaurus, which were long extensions of the vertebrae (or backbones), grew to at least long and were likely to have had skin connecting them, forming a sail-like structure, although some authors have suggested that the spines were covered in fat and formed a hump. Spinosaurus's hip bones were reduced, and the legs were very short in proportion to the body. Its long and narrow tail was deepened by tall, thin neural spines and elongated chevrons, forming a flexible fin or paddle-like structure.
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Life restoration of a juvenile Sciurumimus, with two Pterodactylus in the background Sciurumimus is known from a single holotype fossil that is exceptionally well-preserved, with full skeleton in complete articulation along with fine details of soft tissue. It is comparable in size and proportions to the juvenile coelurosaur Juravenator, although differs significantly in several anatomical details. The skull of Sciurumimus is proportionally large, at 156% of the length of the femur and longer than the cervical vertebrae series. These body proportions, along with short forelimbs, lack of fusion in the skeleton, and regular tooth morphology indicate the specimen represents a very young, probably early-posthatchling individual.
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Cats have seven cervical vertebrae (as do most mammals); 13 thoracic vertebrae (humans have 12); seven lumbar vertebrae (humans have five); three sacral vertebrae (as do most mammals, but humans have five); and a variable number of caudal vertebrae in the tail (humans have only vestigial caudal vertebrae, fused into an internal coccyx). The extra lumbar and thoracic vertebrae account for the cat's spinal mobility and flexibility. Attached to the spine are 13 ribs, the shoulder, and the pelvis. Unlike human arms, cat forelimbs are attached to the shoulder by free-floating clavicle bones which allow them to pass their body through any space into which they can fit their head.
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In the 1980s interest in the site resumed as four wheel drive vehicles became more readily available. Continuing interest coincided with the site being visited by fossil collectors, and many bones were removed, prompting calls for the site to be conserved. The remains display the typical streamlined body form of modern whales, yet retaining some of the primitive aspects of skull and tooth structure. The largest skeleton found reached up to 21 m in length,UNEP-WCMC Protected Areas Programme - Wadi Al-Hitan (Whale Valley) with well-developed five-fingered flippers on the forelimbs and the unexpected presence of hind legs, feet, and toes, not known previously in any archaeoceti.
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Restoration of A. altus Henry Fairfield Osborn and Charles Craig Mook noted the overall close similarity between Amphicoelias and Diplodocus, as well as a few key differences, such as proportionally longer forelimbs in Amphicoelias than in Diplodocus. The femur of Amphicoelias is unusually long, slender, and round in cross section; while this roundness was once thought to be another distinguishing characteristic of Amphicoelias, it has since been found in some specimens of Diplodocus as well. A. altus was also similar in size to Diplodocus, estimated to be about long. The dorsal vertebrae of Amphicoelias are mostly incomplete, but their anatomy is discernible from the known remains.
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Limusaurus is a genus of theropod dinosaur that lived in what is now China during the Late Jurassic, around 161 to 157 million years ago. The type and only species Limusaurus inextricabilis was described in 2009 from specimens found in the Upper Shishugou Formation in the Junggar Basin. The genus name consists of the Latin words for "mud" and "lizard", and the species name means "impossible to extricate", both referring to these specimens possibly dying after being mired. Limusaurus was a small, slender animal, about in length and in weight, which had a long neck and legs but very small forelimbs (with reduced first and fourth fingers).
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Assigned neck vertebra BYU 12866, BYU Museum of Paleontology Ongoing debate revolves around the neck posture of brachiosaurids, with estimates ranging from near-vertical to horizontal orientations. The idea of near-vertical postures in sauropods in general was popular until 1999, when Stevens and Parrish argued that the sauropod neck was not flexible enough to be held in an upright, S-curved pose, and instead was held horizontally. Reflecting this research, various newspapers ran stories criticizing the Field Museum Brachiosaurus mount for having an upward curving neck. Museum paleontologists Olivier Rieppel and Christopher Brochu defended the posture in 1999, noting the long forelimbs and upward sloping backbone.
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Majiashanosaurus is known solely from the holotype AGM-AGB5954, a nearly complete and articulated postcranial skeleton missing, apart from the skull, some neck vertebrae and a small portion of the tail. This skeleton is exposed in ventral view, i.e. from below, and preserves the last three neck vertebrae together with 19 back, three sacral, and more than 18 tail vertebrae, as well as pectoral and pelvic girdles, most of the forelimbs and hindlimbs, and ribs. AGM-AGB5954 was collected at Majiashan, Chaohu of Anhui Province, from the Upper Member of the Nanlinghu Formation, dating to the late Olenekian stage (Spathian) of the late Early Triassic, about 248 million years ago.
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Since the lower end of the third metatarsal would contact the ground first while a theropod was running it would have borne the most stress and should be most predisposed to suffer stress factors more frequently. The lack of such a bias in the examined fossils indicates an origin for the stress fractures from a source other than running, like interaction with prey. They suggested that such injuries could occur as a result of the theropod trying to hold struggling prey with its feet. Contact with struggling prey is also the likely cause of tendon avulsions found in the forelimbs of Allosaurus and Tyrannosaurus.
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Their robust shoulders wielded stocky forelimbs, with three-fingered hands that bore an enlarged claw on the first digit. In many species, the upwards-projecting neural spines of the vertebrae (backbones) were significantly elongated and formed a sail on the animal's back (hence the family's etymology), which supported either a layer of skin or a fatty hump. The genus Spinosaurus, from which the family, subfamily (Spinosaurinae), and tribe (Spinosaurini) borrow their names, is the longest- known terrestrial predator from the fossil record, with an estimated length of up to . The closely related genus Sigilmassasaurus may have reached a similar or greater size, though its taxonomy is disputed.
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Dik-diks are some of the world's smallest antelopes, with the largest, the Kirk's dik-dik, standing between 14 and 18 inches tall and weighing no more than . Female dik-diks tend to be 1 to 2 pounds heavier than males. They are dainty creatures with a pointed, mobile snout, large eyes and ears, prominent preorbital glands, pipestem legs, hare- like hind limbs that are significantly larger than their forelimbs, and a vestigial tail. Their coats, depending upon their habitat, range from grey to gray-brown with tan flanks, limbs, and an erectile head crest and whitish eye rings, ear lining, underparts, and rump.
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Buitreraptor has a slender, flat, extremely elongated snout with many small teeth that lack meat- tearing serrations or cutting edges and are grooved, strongly recurved and flattened. From this, the scientists who initially described it concluded that this dinosaur was not a hunter of relatively large animals like some other dromaeosaurs, but rather a hunter of small animals such as lizards and mammals. The forelimbs of Buitreraptor were long and ended in very long and thin three-fingered hands. All known parts of the hand of Buitreraptor are proportionally longer than in the dromaeosaurids Deinonychus and Velociraptor, except for the ungual bones which are proportionally smaller in Buitreraptor.
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One study recovered Alectrosaurus at no less than eight equally parsimonious positions in a tyrannosauroid cladogram. Some paleontologists have equivocally considered Alectrosaurus olseni to be a species of Albertosaurus. Right humerus of excluded AMNH 6368 Alectrosaurus was originally characterized as a long-armed theropod, but Perle 1977 and Mader & Bradley 1989 observed that the forelimbs of the specimen AMNH 6368 did not belong to the genus, as they do not share characteristics with Tyrannosauroidea, and assigned them to the Therizinosauria incertae sedis. The remaining material, AMNH 6554 represents the hind limb with characteristics of a true tyrannosauroid, and were assigned as the lectotype for Alectrosaurus olseni.
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Euparkeria (; meaning "Parker's good animal", named in honor of W.K. Parker) is an extinct genus of archosauriform from the Middle Triassic of South Africa. It was a small reptile that lived between 245-230 million years ago, and was close to the ancestry of Archosauria, the group that includes dinosaurs, pterosaurs, and modern birds and crocodilians. Euparkeria had hind limbs that were slightly longer than its forelimbs, which has been taken as evidence that it may have been able to rear up on its hind legs as a facultative biped. Although Euparkeria is close to the ancestry of fully bipedal archosaurs such as early dinosaurs, it probably developed bipedalism independently.
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Babakotia radofilai skull Weighing between , Babakotia radofilai was a medium-sized lemur and noticeably smaller than the large sloth lemurs (Archaeoindris and Palaeopropithecus), but larger than the small sloth lemurs (Mesopropithecus). In many ways, it had an intermediate level of adaptations for suspensory behavior between the large sloth lemurs and the small sloth lemurs. This includes its highly mobile hip and ankle joints, as well as other specializations in the vertebral column, pelvis, and limbs. Its forelimbs were 20% longer than its hind limbs, giving it a higher intermembral index (~119) than Mesopropithecus (~97 to 113), suggesting that it was convergently similar to arboreal sloths.
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The etymology of the generic name Tanycolagreus, suggested by Ben Creisler, is based upon the greater length of its forelimbs and hindlimbs compared to Coelurus. It is derived from the Greek prefix τανυ~, tany~: 'long, stretched out', κῶλον, kolon: 'limb' and ἀγρεύς, agreus: 'hunter'. The specific name honours George Eugene "Top" Wilson, the father of a benefactor financially supporting the scientific research.Carpenter, K., Miles, C., and Cloward, K. (2005). "New small theropod from the Upper Jurassic Morrison Formation of Wyoming." in Carpenter, K. 2005. The Carnivorous Dinosaurs, Indiana University Press: 23-48 Restored skeleton The fossil, holotype TPII 2000-09-29, was donated to science by an anonymous benefactor.
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A species of Perameles which, like the Isoodon of the bandicoot family Peramelidae, are terrestrial and somewhat quadrupedal foragers that use short forelimbs to excavate the ground. The hind limbs resemble the macropods, roos and wallabies, and the syndactyly that is typical of diprotodonts, the combined second and third toes of the hindfeet. The body is small and head that is proportionally long, narrow and pointed to suit its use in investigating the sand while digging. Like other peramelids, the pelage of Perameles eremiana is composed of coarse and stiff hair, the coloration of this species is a dull orange with darker bands over the rump.
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This theory has never been discounted, but Osborn, who described and named the dinosaur, proposed that it probably ate buds and shoots from trees, shrubs and other plants, using its forelimbs to grasp branches and its long neck to enable it accurately to select particular items. This herbivorous diet is further supported by the unusual structure of its hands. The second and third fingers were of equal length, could not function independently, and were probably bound together by skin as a single unit. The structure of the shoulder girdle did not allow a high elevation of the arm nor was optimised for a low reach.
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In any case the horse should never move backwards and this is considered a serious fault): ; Passage : A very collected trot, in which the horse has great elevation of stride and seems to pause between each stride (it has a great amount of suspension in the stride). A higher degree of collection causes a definite shift of impulsion to the hindquarters. "An understanding of load distribution between forelimbs and hindlimbs in relation to different riding techniques is vital to prevent wear-and-tear on the locomotor apparatus". ; Extended gaits : Usually done at the trot and canter, the horse lengthens its stride to the maximum length through great forward thrust and reach.
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Last accessed 2008-05-23. Size of P. remotus (green) compared to other small alvarezsaurids Like other members of the family Alvarezsauridae, the forelimbs of Parvicursor were short and stubby, with hands all but completely reduced to a single large claw, possibly useful for opening tough termite mounds or other types of digging. It is unlikely that the claw could have served much for defense, as it was short and not adapted for flexible movements -- it is more likely it would do as the animal's name implies: cursor means runner. Parvicursor is known from the late Campanian-age Barun Goyot Formation of Khulsan, Mongolia, dated at approximately 72 million years old.
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The size range of Allosaurus compared with a human Allosaurus was a typical large theropod, having a massive skull on a short neck, a long, slightly sloping tail and reduced forelimbs. Allosaurus fragilis, the best-known species, had an average length of , with the largest definitive Allosaurus specimen (AMNH 680) estimated at long, and an estimated weight of . In his 1976 monograph on Allosaurus, James H. Madsen mentioned a range of bone sizes which he interpreted to show a maximum length of . As with dinosaurs in general, weight estimates are debatable, and since 1980 have ranged between , , and for modal adult weight (not maximum).
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Tarbosaurus had tiny forelimbs, proportionably to body size the smallest of all members of the family. The hands had two clawed digits each, with an additional unclawed third metacarpal found in some specimens, similar to closely related genera. Holtz has suggested that Tarbosaurus also has a theropod reduction of fingers IV-I "developed further" than in other tyrannosaurids,Carpenter K, Tanke D.H. & Skrepnick M.W. (2001), Mesozoic Vertebrate Life (Indiana University Press, ), p. 71. as the second metacarpal in the Tarbosaurus specimens he studied is less than twice the length of the first metacarpal (other tyrannosaurids have a second metacarpal about twice the length of the first metacarpal).
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Not all dogs who show scratching behavior appear to be in pain, though several leading researchers, including Dr Clare Rusbridge in the UK and Drs Curtis Dewey and Dominic Marino in the US, believe scratching in SM cavaliers is a sign of pain and discomfort and of existing neurological damage to the dorsal horn region of the spine. If onset is at an early age, a first sign may be scratching and/or rapidly appearing scoliosis. If the problem is severe, there is likely to be poor proprioception (awareness of body position), especially with regard to the forelimbs. Clumsiness and falling results from this problem.
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The shoulder girdles of Jeholornis were well developed and probably allowed for better flight capability than seen in Archaeopteryx. The flight apparatus of the Jeholornis was overall quite similar to that of Confuciusornis in form and function, with forelimbs longer than hindlimbs, and a short, robust hand. However, like other primitive (non-ornithothoracean) avialans and theropod dinosaurs, the shoulder blades of Jeholornis were oriented along the sides of the body, rather than on top of its back. This meant that the shoulder girdle was slung low, and according to a 2006 study by Phil Senter, would have allowed only for a typical dinosaurian motion of the shoulder.
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Although the forelimbs are not completely known, they were very short, while the hind limbs were longer and very stocky. It can be distinguished from other abelisaurids by its wider skull, the very rough texture and thickened bone on the top of its snout, and the single rounded horn on the roof of its skull, which was originally mistaken for the dome of a pachycephalosaur. It also had more teeth in both upper and lower jaws than most abelisaurids. Known from several well-preserved skulls and abundant skeletal material, Majungasaurus has recently become one of the best-studied theropod dinosaurs from the Southern Hemisphere.
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Also like related dinosaurs, Majungasaurus had very short forelimbs with four extremely reduced digits, first reported with only two very short external fingers and no claws. The hand and finger bones of Majungasaurus, like other majungasaurines, lacked the characteristic pits and grooves where claws and tendons would normally attach, and its finger bones were fused together, indicating that the hand was immobile. In 2012, a better specimen was described, showing that the lower arm was robust, though short, and that the hand contained four metatarsals and four, probably inflexible and very reduced, fingers, possibly with no claws. The minimum phalanx formula was 1-2-1-1.
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An ostrich walking on a road in Etosha National Park, Namibia As a hugely diverse group of animals, the posture adopted by theropods likely varied considerably between various lineages through time. All known theropods are known to be bipedal, with the forelimbs reduced in length and specialized for a wide variety of tasks (see below). In modern birds, the body is typically held in a somewhat upright position, with the upper leg (femur) held parallel to the spine and with the forward force of locomotion generated at the knee. Scientists are not certain how far back in the theropod family tree this type of posture and locomotion extends.
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In their 2004 phylogenetic analysis, Lü and colleagues classified Nemegtomaia as a derived (or "advanced") oviraptorosaur, and found it to be most closely related to the genus Citipati. In 2010 Longrich and colleagues determined that Nemegtomaia belonged in the family Oviraptoridae, as part of the subfamily Ingeniinae, making it the only member of the latter group with a prominent crest. Members of the other recognised subfamily, Oviraptorinae, all possess crests. Members of this subfamily were distinguished by smaller size, short and robust forelimbs with weakly curved claws, the number of vertebrae in the synsacrum, as well as certain features of the feet and pelvis.
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10011341 The pubis is highly elongated and extends ventrally to form a pubic foot which like in other large dinosaurs is thought to have been used to support the weight of the body in a resting crouch position. Like most other theropods, allosaurids have very short forelimbs relative to their hindlimbs with three digits on the hand and four on the foot. The first digit of the hand forms a semi-opposable thumb and digits 4 and 5 are absent. Digits 2-4 of the foot are robust but digit 1 is reduced and does not touch the ground and digit 5 is absent.
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The parietal parts of the rear edge of the skull frill together bear a single pair of large curved spikes sticking out to behind. Einiosaurus differs from all other known Centrosaurinae by a longer-based and more procurved nasal horn and by a supraorbital horn that is longer-based and more rounded in side view. It differs from Achelousaurus in particular in having large parietal spikes that are not directed sideways to some extent. As a centrosaurine, Einiosaurus walked on all fours, had a large head with a beak, a moderately large skull frill, a short powerful neck, heavily muscled forelimbs, a high torso, powerful hindlimbs and a relatively short tail.
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Comparison of the forelimbs of Deinonychus (left) and Archaeopteryx (right), one of many skeletal similarities between avians and dromaeosaurids Dromaeosaurids share many features with early birds (clade Avialae or Aves). The precise nature of their relationship to birds has undergone a great deal of study, and hypotheses about that relationship have changed as large amounts of new evidence became available. As late as 2001, Mark Norell and colleagues analyzed a large survey of coelurosaur fossils and produced the tentative result that dromaeosaurids were most closely related to birds, with troodontids as a more distant outgroup. They even suggested that Dromaeosauridae could be paraphyletic relative to Avialae.
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He concluded that the Therizinosauridae, Deinocheiridae, and Segnosauridae, which all had enlarged forelimbs, represented the same taxonomic group. Segnosaurus and Therizinosaurus were particularly similar, leading Perle to suggest they belonged in a family to the exclusion of Deinocheiridae (today, Deinocheirus is recognized as an ornithomimosaur). Barsbold retained Segnosaurus and Erlikosaurus in the family Segnosauridae in 1983 and named the new genus Enigmosaurus based on the previously undetermined segnosaurian pelvis. The structure of the pelvis of Erlikosaurus was unknown but Barsbold considered it unlikely the Enigmosaurus pelvis belonged to it because Erlikosaurus and Segnosaurus were so similar in other respects while the pelvis of Enigmosaurus was very different from that of Segnosaurus.
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Several Smilodon fossils show signs of ankylosing spondylitis, hyperostosis and trauma; some also had arthritis, which gave them fused vertebrae. One study of 1,000 Smilodon skulls found that 30% of them had eroded parietal bones, which is where the largest jaw muscles attach. They also showed signs of microfractures, and the weakening and thinning of bones possibly caused by mechanical stress from the constant need to make stabbing motions with the canines. Bony growths where the deltoid muscle inserted in the humerus is a common pathology for a La Brea specimen, which was probably due to repeated strain when Smilodon attempted to pull down prey with its forelimbs.
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The osteoderms also sport keels on their underside that lock neatly into the furrow in their vertebrae, which could suggest the osteoderms were restricted to the neck and front-most section of the back as the 'Y'-shaped spine tables are not found past the 4th dorsal vertebra. This would be unusual, but not completely unprecedented as some pseudosuchians (particularly ornithosuchids) are known to have only had osteoderms in front of the hips, although not to the extent in Aenigmaspina. The scapula is very long and slender with little curve along its length, suggesting a tall, narrow body shape. The glenoid (shoulder joint) faces down and slightly back, suggesting upright forelimbs.
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Turtle lungs are attached to the inside of the top of the shell (carapace), with the bottom of the lungs attached (via connective tissue) to the rest of the viscera. By using a series of special muscles (roughly equivalent to a diaphragm), turtles are capable of pushing their viscera up and down, resulting in effective respiration, since many of these muscles have attachment points in conjunction with their forelimbs (indeed, many of the muscles expand into the limb pockets during contraction). Breathing during locomotion has been studied in three species, and they show different patterns. Adult female green sea turtles do not breathe as they crutch along their nesting beaches.
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The toes have moderate webbing. The dorsum has four pairs of longitudinal dermal folds, of which the outer pair is prominent, whereas the inner ones are less well- defined, partly broken into clusters of large, rounded warts. Dorsal colouration is cream or pale grey-brown to dark olive-brown. The dorsal skin folds, upper flanks, upper surface of forelimbs, outer edge of hind limbs, upper eyelids, and lips have often suffused to a variable degree with pink, reddish, or purplish pigment, There are dark grey to black markings on the back that vary from being almost obsolete to relatively numerous and prominent, at least dorsolaterally.
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Pachycephalosaurs were bipedal ornithischians characterized by their thickened skulls. They had a bulky torso with an expanded gut cavity and broad hips, short forelimbs, long legs, a short, thick neck, and a heavy tail. Large orbits and a large optic nerve point to pachycephalosaurs having good vision, and uncharacteristically large olfactory lobes indicate that they had a good sense of smell relative to other dinosaurs. They were fairly small dinosaurs, with most falling in the range of 2–3 meters (6.6-9.8 feet) in length and the largest, Pachycephalosaurus wyomingensis, estimated to measure 4.5 meters (14.8 feet) long and weigh 450 kilograms (990 pounds).
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The forelimbs also preserved the major and minor metacarpals as well as the finger bones showing a phalangeal formula of 2-3-2. The hind limbs have a robust and bowed femur, a tibia which is slightly longer than the femur, and a slender fibula. They also preserve four metatarsals (metatarsal V is not preserved) where metatarsals II-IV, are not fused to each other and where metatarsal III is the longest and widest, while the others are equal in length Feathers are preserved in the holotype and one of the two most recent finds, where they are associated with the neck, wing and tail regions.
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Limusaurus and bird digit identity. Available from Nature Precedings A small minority, known by the acronym BAND (Birds Are Not Dinosaurs) including ornithologists Alan Feduccia and Larry Martin, continues to assert that birds are more closely related to earlier reptiles, such as Longisquama or Euparkeria, than to dinosaurs. Embryological studies of bird developmental biology have raised questions about digit homology in bird and dinosaur forelimbs. However, due to the cogent evidence provided by comparative anatomy and phylogenetics, as well as the dramatic feathered dinosaur fossils from China, the idea that birds are derived dinosaurs, first championed by Huxley and later by Nopcsa and Ostrom, enjoys near-unanimous support among today's paleontologists.
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The squamosal horns of the largest Ankylosaurus specimen are blunter than those of the smallest specimen, which is also the case in Euoplocephalus, and this may represent ontogenetic variation (related to growth development). Studies of specimens of Pinacosaurus of different ages found that during ontogenetic development, the ribs of juvenile ankylosaurs fused with their vertebrae. The forelimbs strongly increased in robustness while the hindlimbs did not become larger relative to the rest of the skeleton, further evidence that the arms bore most of the weight. In the cervical half-rings, the underlying bone band developed outgrowths connecting it with the underlying osteoderms, which simultaneously fused to each other.
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More derived castorids have less complex occlusion, upper tooth rows which diverge posteriorly, larger second premolars in comparison to molars, loss of P3 and stapedius and more grooved palatine with a palatine foramen shifted towards the front. Members of the subfamily Palaeocastorinae appeared in late Oligocene North America. This group was small-bodied and adapted to a fossorial or burrowing lifestyle, with relatively large forelimbs, a low, broad skull and short tail. In the early Miocene (about 24 mya), castorids evolved a semiaquatic lifestyle and developed the ability to cut down trees and build infrastructure, an ability that allowed them to survive in the harsh winters of Arctic latitudes.
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The shrew-mole is often confused with pocket gophers, another group of fossorial subterranean mammals, because they have similar habits but they differ greatly in the methods for burrowing. Most fossorial mammals, including the pocket gophers dig with their forepaws held directly below their body, but shrew- moles dig using lateral-strokes. This method of lateral-stroke burrowing in shrew moles is an evolutionary adaptation due to the modification of the pectoral girdle and bones of the forelimbs. The pelvic girdle is small and unmodified, but the pectoral girdle contains a special joint that causes the clavicle to join with the humerus instead of the scapula.
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Its tail is particularly long, sometimes two-thirds of the overall length, and is used in a prehensile manner to stabilize the animal in the branches. In fact, the tail is used solely for this purpose, as the animal does not evince the defensive tail-lashing behaviour seen in other monitor species. Like other tree monitors, they sport some of the longest and most slender forelimbs of all monitors, which end in elongated digits tipped with large claws and adhesive soles, helping it maintain grip in the trees and catch prey. It also has unusually long teeth for a monitor of its size, which may help it to hold on to prey it catches in the canopy.
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Skull of Euromycter rutenus in ventral view allowing to see the numerous small teeth adorning the bones of the palate (the parasphenoid, triangular in shape in the center, and the very elongated pterygoids on each side). The hyoid apparatus is not present here because it was removed during the preparation of the palate. The skull is well-preserved but has suffered of a slight flattening as a result of a tectonic thrust exerted toward the right side and the front. As in other caseid, the skull is small compared to the skeleton (here mainly the forelimbs), and shows very large external nares, a short facial region, and a dorsal surface of the skull dotted of numerous small depressions.
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Later, in 2017, another team re- evaluated the specimen, and determined through investigating the fossils at a microscopic level (in a process called histology) that this was correct, although they doubted the significance of some of the characters identified in the former study. Though the quality of bone preservation is generally poor, the holotype skeleton is estimated to be 60% complete. It consists of a left maxilla and dentary, parietal, various isolated skull elements, thirteen cervical vertebrae, six dorsal vertebrae, two sacral vertebrae, a series of 35 caudal vertebrae, a left scapula, lower portions of both humeri, most elements of the lower forelimbs, an ischium, left ilium, and most of the hindlimbs.
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Scale diagram of Ufudocyclops to a human Ufudocyclops is a large dicynodont, with the largest specimen reconstructed to have an estimated skull length of and the smaller complete holotype skull at approximately long, and an estimated overall body size similar to that of Kannemeyeria. Only skulls and one partial lower jaw are definitively known, and no postcrania from the body has been identified, but it likely resembled other stahleckeriid dicynodonts with a heavily-built body, short tail, and stocky limbs, possibly including upright hind-limbs paired with sprawling forelimbs like other large dicynodonts. Like some other stahleckeriids, Ufudocyclops appears to have lacked the tusks characteristic of many other dicynodonts, and was completely toothless.
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A four-toed elephant shrew has long, soft fur and its color varies from greyish pale brown to dark brown with white rings around its eyes, and wide dark stripes on its back. Markings of the four-toed elephant shrew vary in colour: the upper parts of its feet are brownish-yellow; its ears are dark brown, with pure white hair on the base of the inner margin; the tail is black on the upper side and pale yellow-brown on the underside, darkening in the middle and almost black at tip. The four-toed elephant shrew has a long, pointed, flexible and sensitive snout, which it uses to hunt. It also has short forelimbs and long back limbs.
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Amblysomus is part of the family of golden moles, Chrysochloridae. The order of golden moles and tenrecs, Afrosoricida, is part of Afrotheria, one of the four main divisions of placental mammals, along with elephant shrews, aardvarks, hyraxes, sirenians and elephants. Golden moles are not all golden. Some have black to pale tawny-yellow fur.; the name and family name “Chrysochloridae” (meaning green-gold), refers to the coppery gold, green, purple or bronze sheen of their dense fur. They all have differences in size and color, but have a similar appearance” with compact fusiform or lozenge- shaped bodies, short and powerful forelimbs containing pick-like claws, and no external eyes, ears or tail”.
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In 1912, Maurice G. Mehl questioned the assignment of C. laramiensis to Cimoliosaurus, noting that Cimoliosaurus was a catch-all, and that since this genus was named based on vertebrae, the vertebrae of C. laramiensis would have to be similar to those of the type species, C. magnus. He was unable to find such similarities, and provisionally reclassified C. laramiensis as a species of Tricleidus, due to the anatomy of its forelimbs. Although the holotype specimen of T. laramiensis has since been lost, Knight's description of the specimen was sufficient to determine that T. laramiensis is a valid species. In 2003, F. Robin O'Keefe and William Wahl, JR. referred another specimen housed at the Tate Museum to this species.
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For bat embryos, apoptosis (cell death) affects only the hindlimbs, while the forelimbs retain webbing between the digits that forms into the wing membranes. Unlike birds, whose stiff wings deliver bending and torsional stress to the shoulders, bats have a flexible wing membrane that can resist only tension. To achieve flight, a bat exerts force inwards at the points where the membrane meets the skeleton, so that an opposing force balances it on the wing edges perpendicular to the wing surface. This adaptation does not permit bats to reduce their wingspans, unlike birds, which can partly fold their wings in flight, radically reducing the wing span and area for the upstroke and for gliding.
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Restoration Characteristics of the limbs of Aardonyx suggest that it was habitually bipedal. Evidence for bipedalism can be seen in the forelimbs; the structure of the radius and ulna limited the degree to which the manus could be pronated, and the length of the humerus is only 72 percent that of the femur. However, characteristics found in both the fore and hind limbs of Aardonyx show a trend toward more habitual quadrupedalism that would eventually lead to the obligatory quadrupedalism seen in sauropods. The proximal end of the ulna possesses an incipient craniolateral process that gives the bone a y-shape similar to, although more subtle than, those of obligatory quadrupedal sauropodomorphs.
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The light produced is of lower intensity than the light produced by typical sonoluminescence and is not visible to the naked eye. The light and heat produced may have no direct significance, as it is the shockwave produced by the rapidly collapsing bubble which these shrimp use to stun or kill prey. However, it is the first known instance of an animal producing light by this effect and was whimsically dubbed "shrimpoluminescence" upon its discovery in 2001. It has subsequently been discovered that another group of crustaceans, the mantis shrimp, contains species whose club-like forelimbs can strike so quickly and with such force as to induce sonoluminescent cavitation bubbles upon impact.
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Fossil under preparation The type specimen was described and named by Canale, Scanferla, Agnolin, and Novas in 2009 (though the paper was released as an advanced publication online in 2008). The name Skorpiovenator bustingorryi is derived from the Greek and Latin for "scorpion hunter," due to the abundant scorpions present at the dig site, and the specific name honors Manuel Bustingorry, who owned the farm where the specimen was found. The describers have defined a new name Brachyrostra for a clade, to which Skorpiovenator belonged. The type species, Skorpiovenator bustingorryi, is known from a single, nearly complete skeleton (MMCH-PV 48K) missing only sections of the tail and the majority of the forelimbs.
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Its remains came from the Konservat-Lagerstätte of Las Hoyas, Cuenca, Spain. The holotype (LH13500), housed in the collection of , consists on both slab and counterslab preserving mainly the thoracic region, part of the neck and both almost complete forelimbs of an adult specimen. It also preserves remains of the body, primary, secondary feathers and a bastard wing which have been covered by layers of limonite as a result of the fossilization process. The preservation is consistent with the taphonomic processes associated with obruption, stagnation and the action of microbial mats in the locality (1997): "The mineralization of dinosaur soft tissue in the Lower Cretaceous of Las Hoyas, Spain", Journal of the Geological Society, vol.
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In the initial descriptions of the first two scansoriopterygid specimens, scientists studying these animals used several lines of evidence to argue that they were arboreal (tree-climbing), and the first known non-avian dinosaurs with clear climbing adaptations. Zhang and colleagues considered Scansoriopteryx to be arboreal based on the elongated nature of the hand and specializations of the foot. These authors stated that the long hand and strongly curved claws were adaptations for climbing and moving around among tree branches. They viewed this as an early stage in the evolution of the bird wing, stating that the forelimbs became well-developed for climbing, and that this development later led to the evolution of a wing capable of flight.
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Reconstructed hypothetical skull based on Masiakasaurus In 1980, it was thought that the presumed foot claw functioned as a sickle claw. Paul in 1988 saw the noasaurines as the South-American counterparts of the Asian and North-American dromaeosaurids, in a process of convergent evolution. Noting that abelisaurids tend to have very short arms, he wondered whether the forelimbs of Noasaurus were of limited length also, forcing the animal to employ a kicking technique instead of grasping the back of a victim in order to disembowel it with the foot claws, a method he assumed the dromaeosaurids used.This hypothesis was undermined when it was determined that the foot claw was in fact a hand claw.
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Sarahsaurus was a basal (or "primitive") member of the sauropodomorph lineage, which also included the more derived (or "advanced") sauropods – giant four-legged herbivores (plant- eaters) with long necks and tails. Basal sauropodomorphs such as Sarahsaurus already resemble sauropods in a number of aspects, including the elongated neck and robust build, but are reminiscent of the ancestral dinosaurs in others: Sarahsaurus was bipedal (two-legged), with forelimbs that were much shorter than the hind limbs and equipped with powerful grasping hands. Sarahsaurus was mid-sized for a basal sauropodomorph, with its vertebral column measuring more than in length. Paleontologist Gregory Paul, in a 2016 popular book, estimated its length at and its body weight at .
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Its forelimbs, ossified tendons, and skin impressions were briefly described in 1913 and 1914 by Lambe, who at first thought it was an example of a species he had named Trachodon marginatus, but then changed his mind. The specimen became the first dinosaur skeleton to be mounted for exhibition in a Canadian museum. Gilmore found that his new species compared closely to what he called Thespesius annectens, but left the two apart because of details of the arms and hands. He also noted that his species had more vertebrae than Marsh's in the back and neck, but proposed that Marsh was mistaken in assuming that the annectens specimens were complete in those regions.
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Restoration of Acrocanthosaurus engaging in alt= Like those of most other non-avian theropods, Acrocanthosaurus forelimbs did not make contact with the ground and were not used for locomotion; instead, they served a predatory function. The discovery of a complete forelimb (NCSM 14345) allowed the first analysis of the function and range of motion of the forelimb in Acrocanthosaurus. The study examined the bone surfaces which would have articulated with other bones to determine how far the joints could move without dislocating. In many of the joints, the bones did not fit together exactly, indicating the presence of a considerable amount of cartilage in the joints, as is seen in many living archosaurs.
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The holotype skeleton, STMN 26-3STMN 26-3 consists of an incomplete skeleton preserving a partial skull and mandible, partial presacral vertebrae, proximal–middle caudal vertebrae, nearly complete right scapula, both humeri, the proximal end of the left ulna, partial pubes, both ischia, both femora, the right tibia and fibula and pes, as well as remains of long, singular and unbranched filamentous integumentary structures. The holotype is from a subadult individual that probably measured 70 cm in length based on the proportions of the related South African species Heterodontosaurus tucki. However, Tianyulong had unusual proportions compared to other heterodontosaurids. The head was large and the legs and tail were long, but the neck and forelimbs were short.
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Ancalecetus (from Greek ankale, "bent arm", and ketos, "whale") is an extinct genus of early whale known from the Late Eocene (Priabonian, ) Birket Qarun Formation (, paleocoordinates ) in Wadi Al-Hitan, Egypt.. Retrieved July 2013.. Retrieved July 2013. The species is named after anthropologist and primate researcher Elwyn L. Simons who discovered the type specimen in 1985. The holotype is a partial cranium (the top of the skull was destroyed by erosion), both dentaries, 20 vertebrae and some sternal elements, partial ribs, and most of both forelimbs. Ancalecetus differs from other archaeocetes and modern whales in having narrow scapulae, very limited mobility in the shoulder joint, and fusion of the humerus, ulna, and radius at the elbow joint.
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Madsen noted that in about half of the individuals from the Cleveland-Lloyd Dinosaur Quarry, independent of size, the pubes had not fused to each other at their foot ends. He suggested that this was a sexual characteristic, with females lacking fused bones to make egg-laying easier. This proposal has not attracted further attention, however. Hand and claws of A. fragilis The forelimbs of Allosaurus were short in comparison to the hindlimbs (only about 35% the length of the hindlimbs in adults) and had three fingers per hand, tipped with large, strongly curved and pointed claws. The arms were powerful, and the forearm was somewhat shorter than the upper arm (1:1.2 ulna/humerus ratio).
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Fossil of Tianyulong, muzzle, hand, feet and tail framed in red The postcranial anatomy of Heterodontosaurus tucki has been well-described, although H. tucki is generally considered the most derived of the Early Jurassic heterodontosaurids, so it is impossible to know how many of its features were shared with other species. The forelimbs were long for a dinosaur, over 70% of the length of the hindlimbs. The well-developed deltopectoral crest (a ridge for the attachment of chest and shoulder muscles) of the humerus and prominent olecranon process (where muscles that extend the forearm were attached) of the ulna indicate that the forelimb was powerful as well. There were five digits on the manus ('hand').
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"Politics and Paleontology". The Complete Dinosaur, 175–190. Lithograph of the Maidstone specimen In 1849, a few years before his death in 1852, Mantell realised that the genus today known as Mantellodon was not a heavy, pachyderm-like animal, as Owen was putting forward, but had slender forelimbs; however, his passing left him unable to participate in the creation of the Crystal Palace dinosaur sculptures, and so Owen's vision of the dinosaurs became that seen by the public for decades. With Benjamin Waterhouse Hawkins, Owen had nearly two dozen lifesize sculptures of various prehistoric animals built out of concrete sculpted over a steel and brick framework; two Mantellodon, one standing and one resting on its belly, were included.
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Skeletal mount of the Tyrannosaurus holotype. This timeline of tyrannosaur research is a chronological listing of events in the history of paleontology focused on the tyrannosaurs, a group of predatory theropod dinosaurs that began as small, long-armed bird-like creatures with elaborate cranial ornamentation but achieved apex predator status during the Late Cretaceous as their arms shrank and body size expanded. Although formally trained scientists did not begin to study tyrannosaur fossils until the mid-19th century, these remains may have been discovered by Native Americans and interpreted through a mythological lens. The Montana Crow tradition about thunder birds with two claws on their feet may have been inspired by isolated tyrannosaurid forelimbs found locally.
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Like sauropods, its forelimbs were much longer relative to its hind legs than earlier animals, while the metatarsus was shortened. However, the first digit of the hand, also called the "thumb" or pollex, was still twisted and flexible, capable of grasping against the hand. In more derived sauropods, the wrist bones are large and thick, arranged in such a way as to lock the hand into a permanently pronated position for full-time weight support, and the hand is incapable of grasping. Antetonitrus already shows adaptations for an increasing body size as seen in all later sauropods: The wrist bones were broader and thicker to support more weight, whereas the femur was elliptical in cross section.
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On the other hand, a pathological study of Odontochelys performed by Rothschild & Naples (2015) discovered that both the left and right humeri (forearm bones) of the paratype specimen (IVPP 13240) of Odontochelys had been degraded near the shoulder sockets. The study rejected explanations such as weathering or a wound-induced bone infection, arguing that it would not have made sense for the shoulder area to degrade before the rest of the forelimbs, since the shoulder was more well-protected during life and after death. Instead, the study argued that decompression sickness was responsible for the injury. This condition has been observed in diving animals which are forced to make rapid ascents within a deep marine environment.
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Tetrapod forelimbs are characterised by a high degree of mobility in the shoulder- thorax connection. Lacking a solid skeletal connection between the shoulder girdle and the vertebral column, the forelimb's attachment to the trunk is instead mainly controlled by serratus lateralis and levator scapulae. Depending on locomotor style, a bone connects the shoulder girdle to the trunk in some animals; the coracoid bone in reptiles and birds, and the clavicle in primates and bats; but cursorial mammals lack this bone. In primates, the shoulder shows characteristics that differ from other mammals, including a well developed clavicle, a dorsally shifted scapula with prominent acromion and spine, and a humerus featuring a straight shaft and a spherical head.
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Talpids are small, dark-furred animals with cylindrical bodies and hairless, tubular snouts. They range in size from the tiny shrew moles of North America, as small as 10 cm in length and weighing under 12 grams, to the Russian desman, with a body length of 18–22 cm, and a weight of about 550 grams. The fur varies between species, but is always dense and short; desmans have waterproof undercoats and oily guard hairs, while the subterranean moles have short, velvety fur lacking any guard hairs. The forelimbs of moles are highly adapted for digging, with powerful claws, and the paws turned permanently outwards to aid in shovelling dirt away from the front of the body.
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This parallels the way some herbivorous mammals use their forelimbs to manipulate vegetation; Russell considered the extinct chalicotheres and ground sloths, as well as gorillas, adaptively convergent with therizinosaurs. Because therizinosaur remains are often found in sediments deposited in river and lake environments, Russell said they may have browsed on riparian bushes and trees. Based on the assemblage of fossils in the Bissekty Formation of Uzbekistan, Nessov suggested in 1995 that therizinosaurs could have been part of its nutrient-rich aquatic ecosystems, though perhaps indirectly, by feeding on wasps which had themselves fed on carrion of aquatic vertebrates. He found this consistent with Rozhdestvensky's suggestion that therizinosaurs may have fed on social insects.
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Compared to S. fatalis, S. populator was more robust and had a more elongated and narrow skull with a straighter upper profile, higher positioned nasal bones, a more vertical occiput, more massive metapodials and slightly longer forelimbs relative to hindlimbs. Large tracks from Argentina (for which the ichnotaxon name Smilodonichium has been proposed) have been attributed to S. populator, and measure by . This is larger than tracks of the Bengal tiger, to which the footprints have been compared. S. fatalis restored with spotted coat Traditionally, saber-toothed cats have been artistically restored with external features similar to those of extant felids, by artists such as Charles R. Knight in collaboration with various paleontologists in the early 20th century.
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In 2012 Holtz estimated it at 6.5 meters (24 feet), while in 2016 Molina-Pérez & Larramendi gave a higher estimation at 9.3 meters (30.5 feet) in length and 1 tonne (1.1 short tons) in weight. A cladistic analysis indicated Austrocheirus had a basal position in the Abelisauroidea, but was more derived than Ceratosaurus and Berberosaurus. This would make it the first known mid-sized abelisauroid which did not possess the reduced forelimbs seen in other members of that clade. The referral of Austrocheirus to Abelisauroidea was challenged by Oliver Rauhut (2012), who claimed that the putative abelisauroid synapomorphies used to justify this referral are actually also present in the skeletons of non-abelisauroid theropods.
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Bengal tiger skeleton on display at the Museum of Osteology The tiger has a muscular body with powerful forelimbs, a large head and a tail that is about half the length of its body. Its pelage is dense and heavy, and colouration varies between shades of orange and brown with white ventral areas and distinctive vertical black stripes that are unique in each individual. Stripes are likely advantageous for camouflage in vegetation such as long grass with strong vertical patterns of light and shade. The tiger is one of only a few striped cat species; it is not known why spotted patterns and rosettes are the more common camouflage pattern among felids.
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A red kangaroo skull at the Museum Wiesbaden, Hessen A female red kangaroo at Botanic Garden Zoo in Wagga Wagga, Australia This species is a very large kangaroo with long, pointed ears and a square shaped muzzle [snout/nose]. They are sexually dimorphic as the males have short, red-brown fur, fading to pale buff below and on the limbs. Females are smaller than males and are blue-grey with a brown tinge, pale grey below, although arid zone females are coloured more like males. It has two forelimbs with small claws, two muscular hind- limbs, which are used for jumping, and a strong tail which is often used to create a tripod when standing upright.
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Loss of function or decreased expression could result in the malformation or absence of essential limb components. Studies have shown that the forelimbs tend to be more affected by the loss of FGF8 signaling than the hindlimbs and the loss tends to affect the proximal components more heavily than the distal components. FGF8 not only aids in the formation of the limb bud and skeletal components of the limb, but the tendons within the limb are affected by it near the portions closest to the muscle extremities. This diffusible polypeptide is responsible for inducing the limb bud, then inducing and maintaining sonic hedgehog expression in the established limb bud promoting outgrowth of the limb.
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Forelimbs of Therizinosaurus, specimen IGM 100/15 displayed at Nagoya City Science Museum Therizinosaurs were long considered an enigmatic group, whose mosaic of features resembling those of various different dinosaur groups, and scarcity of their fossils, led to controversy over their evolutionary relationships for decades after their initial discovery. The first genus, Therizinosaurus, was originally identified as a turtle when described from forelimb elements in 1954. Translated paper Perle noted in 1979 that the Segnosaurus fossils were possibly representative of a new family of dinosaurs, which he tentatively classified as theropods (traditionally thought of as the "meat-eating" dinosaurs). He named the family Segnosauridae, with Segnosaurus as type genus and sole member.
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Among the bizarre and unique features are a mediolaterally compressed and antero-posteriorly bowed tibia, a double trochlea on the astragalus, a fully developed humeral trochlea, and an unusually high number of trunk vertebrae. The new taxon has at least 19 rib- bearing (thoracic) and 11 non-rib-bearing (lumbar) vertebrae. Aside from these derived features, the Malagasy mammal has a mosaic pectoral girdle morphology: the procoracoid is lost, the coracoid is extremely well developed (into an enlarged process that contributes to half of the glenoid fossa), the interclavicle is small, and the sternoclavicular joint appears mobile. A ventrally-facing glenoid and the well-developed humeral trochlea suggest a relatively parasagittal posture for the forelimbs.
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The clavicle bones are thick and rounded at their base but taper as they extend outwards (and upwards in the case of a living animal). No conclusive evidence of a pelvic girdle or hindlimbs have been found, although Carroll (1969) considered that a few bone fragments around the 26th to 31st vertebrae may have been leg bones. As a whole, the lack of known limb and endochondral material yet the retention of a dermal shoulder girdle is a condition similar to that of the other family of adelospondyls, the adelogyrinids. Although forelimbs were supposedly found in various adelogyrinids in the late 1960s, Andrews & Carroll (1991) found that all cases of forelimb bones in adelogyrinids were actually misinterpretations.
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It is notable, however, that the sunbittern and the mesites possess powder down too, whereas the "core Gruiformes" do not. While the kagu is the only living species in the clade Rhynochetidae, a larger species, the lowland kagu (Rhynochetos orarius), has been described from Holocene subfossil remains. The measurements of this species were 15% bigger than Rhynochetos jubatus, with no overlap in measurements except those of the forelimbs. Given that the sites from which R. orarius remains have been recovered are all lowland sites, and that no fossils of R. jubatus have been found in these sites, the scientists that described the fossils have suggested that they represent highland and lowland species respectively.
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In reality, the hand bones of stegosaurians were arranged into vertical columns, with the main fingers, orientated outwards, forming a tube-like structure. This is similar to the hands of sauropod dinosaurs, and is also supported by evidence from stegosaurian footprints and fossils found in a lifelike pose. Stegosaurus mount showing to a good effect the high neck posture, the throat ossicles and the robust shoulder girdle and forelimbs The long hindlimbs elevated the tail base, such that the tail pointed out behind the animal almost horizontally from that high position. While walking, the tail would not have sloped downwards as this would have impeded the function of the tail base retractor muscles, to pull the thighbones backwards.
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Freely articulated forearm bones (radius and ulna) permitted their powerful forelimbs wide rotational movements, while their digits had large bony claws indicating they could dig and build underground dens. Their powerful hind limbs could not be rotated in the same way, but the prominent transverse processes of the first tail vertebra suggest that they used their powerful tails to propel through the water like modern otters. In later pantolestids there is a prominent cranial crest combined with strong spinal processes, indicating the presence of strong neck muscles needed by swimmers that constantly hold their heads above the water surface. The youngest pantolestids known are Gobiopithecus khan and Kiinkerishella zaisanica from the Ergilian deposits of Khoer Dzan, Mongolia.
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Compared to modern crocodilians, goniopholids are very unusual in several respects. They possessed two rows of rectangular, interlocking osteoderms like those of terrestrial crocodilymorphs like atoposaurids, that are relatively simple, do not extend far in their necks, as opposed to the ornate armours of modern crocodilians; likewise, unlike modern crocodilians but like many extinct forms like phytosaurs, they have ventral osteoderms as well. Their forelimbs are also proportionally very long, particularly in the humeri and wrist bones, being as long or longer than the hindlimbs, the opposite of the condition seen in modern crocodilians. Some like Anteophthalmosuchus also have forwardly oriented eyes, as opposed to the dorsally oriented eyes seen in modern forms.
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On the ground sifakas move like all indrids with bipedal sideways hopping movements of the hind legs, holding their forelimbs up for balance. Geladas, although usually quadrupedal, will sometimes move between adjacent feeding patches with a squatting, shuffling bipedal form of locomotion. Humans are the only primates who are normally biped, due to an extra curve in the spine which stabilizes the upright position, as well as shorter arms relative to the legs than is the case for the nonhuman great apes. The evolution of human bipedalism began in primates about four million years ago, or as early as seven million years ago with Sahelanthropus or about 12 million years ago with Danuvius guggenmosi.
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Based on the isolated fossil remains of a large chelicera (claw) from the Klerf Formation of Germany, J. rhenaniae has been estimated to have reached a size of around 2.3–2.6 metres (7.5–8.5 ft), making it the largest arthropod ever discovered, surpassing other large arthropods such as fellow eurypterids Acutiramus and Pterygotus and the millipede Arthropleura. J. howelli was much smaller, reaching 80 centimetres (2.6 ft) in length. In overall appearance, Jaekelopterus is similar to other pterygotid eurypterids, possessing a large, expanded telson (the hindmost segment of the body) and enlarged pincers and forelimbs. Both species of Jaekelopterus were first described as species of the closely related Pterygotus but were raised as a separate genus based on an observed difference in the genital appendage.
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The forelimbs appear to have become proportionally longer during growth, whereas the proportional length of the bones in the hind limbs changed very little. In 2012, palaeontologist Darla K. Zelenitsky and colleagues concluded that, since adult ornithomimosaurs had wing-like structures on their arms whereas juveniles did not (as evidenced by specimens of Ornithomimus), these structures were originally secondary sexual characteristics, which could have been used for reproductive behaviour such as courtship, display, and brooding. A 1987 study by the biologists Roman Pawlicki and P. Bolechała showed age-related differences in the content of calcium and phosphorus (important components in the formation of bone) of Gallimimus specimens. They found that the ratio was highest in young to middle aged animals, decreasing with age.
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The lower rump is covered by a basket of eighteen pairs of gastralia or belly ribs. Mysterious shaft parts present near the forelimbs are by Dal Sasso & Maganuco interpreted as the remains of a nineteenth frontmost element consisting of two completely fused shafts homologous to the normal medial elements of a pair of gastralia; such a chevron-like bone has also been reported with Juravenator. The gastralia form a herringbone pattern, the left and right medial elements overlapping each other at their forked ends in order that the basket can expand and contract to accommodate the breathing movements of the abdomen. The scapula is relatively straight and about six to seven times longer than wide; its upper end is missing.
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Earlier arguments for a sprawling stance include deep pelvises and features of the legs. They also suggested that the feet of multituberculates would have been plantigrade (the sole touching the ground) at rest, but digitigrade (the sole not touching the ground) when jumping and running quickly; they dismissed the idea that the forelimbs of multituberculates and other early mammals were more parasagittal than their hindlimbs. Kielan-Jaworowska and Hurum depicted Catopsbaatar with plantigrade, sprawling legs, with mobile spurs which pointed inward when preparing for attack. In 2008, Kielan-Jaworowska and Hurum suggested that the long spinous process on a Catopsbaatar vertebra and the long transverse processes in Nemegtbaatar may indicate that some multituberculates were saltatorial (had the ability to jump).
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It consists of a partial, sub-adult, skeleton that is largely disarticulated. A significant number of fossilized bones were recovered, including: cranial fragments, a mandible, teeth, three cervical vertebrae, four dorsal vertebrae, four dorsal ribs, two sacral vertebrae, twenty-five caudal vertebrae with a pygostyle, three chevrons, an incomplete furcula and scapula, both coracoids, both forelimbs, both ilia, an incomplete pubis, an incomplete ischium, a femur, both tibiae (one incomplete), an incomplete fibula, the astragalus and calcaneum, several tarsals, metatarsals, manual and pedal unguals, and skin impressions of the primitive plumage. The pelvic girdle and caudal vertebrae were discovered during a re-excavation of the fossil quarry were the first elements of the holotype were found. These rediscovered elements helped to complete the holotype specimen.
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Paul (2000) p. 107. Some of these models were initially created for the Great Exhibition of 1851, but 33 were eventually produced when the Crystal Palace was relocated to Sydenham, in South London. Owen famously hosted a dinner for 21 prominent men of science inside the hollow concrete Iguanodon on New Year's Eve 1853. However, in 1849, a few years before his death in 1852, Gideon Mantell had realized that Iguanodon, of which he was the discoverer, was not a heavy, pachyderm-like animal, as Owen was putting forward, but had slender forelimbs; his death left him unable to participate in the creation of the Crystal Palace dinosaur sculptures, and so Owen's vision of dinosaurs became that seen by the public.
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The overall robustness of the skeleton of Xingxiulong, especially in the hip, femur, and foot, are convergent upon sauropods, and collectively suggest that it had a relatively large gut and overall high body mass. However, unlike sauropods, Xingxiulong would have been bipedal; it lacks sauropodan adaptations to quadrupedalism including relatively longer forelimbs, the ulna bearing a prominent process on the front of its side, and the femur having a relatively straight shaft. Instead, its ulna and femur are overall more reminiscent of the typical basal sauropodomorph. The large and robust scapulae of Xingxiulong, Jingshanosaurus, and Yunnanosaurus may have increased the mobility of the forelimb during bipedal browsing, but this trait was later adopted as an adaptation to quadrupedality in sauropods.
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Further, these three could be regarded as extreme geographical variations within the one taxon. This group was hypercanivorous, had a large body size that is comparable with the northern populations of the modern gray wolf (Canis lupus) and are characterized by a short neurocranium relative to their skull size. The ancestral condition for canids is to have five toes on their forelimbs, but by the Early Pleistocene this lineage had reduced this to four, which is also a characteristic feature of the modern African wild dog (Lycaon pictus). The African wild dog cannot be positively identified in the fossil record of eastern Africa until the middle Pleistocene, and identifying the oldest Lycaon fossil is difficult because these are hard to distinguish from Canis (Xenocyon) africanus.
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Reconstructed forelimb and hand of Suchomimus, Museum of Ancient Life, Utah The use of the robust forelimbs and giant recurved claws of spinosaurs remains a debated topic. Charig and Milner speculated in 1986 that Baryonyx may have crouched by the riverbank and used its claws to gaff fish out of the water, similarly to grizzly bears. In 1987, British biologist Andrew Kitchener argued that with both its crocodile-like snout and enlarged claws, Baryonyx seemed to have too many adaptations for piscivory when one would have been enough. Kitchener instead postulated that Baryonyx more likely used its arms to scavenge the corpses of large dinosaurs, such as Iguanodon, by breaking into the carcass with the large claws, and subsequently probing for viscera with its long snout.
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Finally, it possesses comparatively longer forelimbs than other known pliosaurids, with a long humerus, more than 7 times the average width of cervical vertebral centra, in comparison to P. brachyspondylus and P. rossicus, which have humeri less than 4.5 times the cervical width. Its complete teeth count is not known, however, it has at least six pairs of teeth in the mandibular symphysis, and at least five premaxillary tooth pairs. The two known individuals of P. funkei preserve mostly different regions of the skeleton and overlap only by cervical vertebrae. Nevertheless, these cervical vertebrae are morphologically indistinguishable, and both individuals were found in proximity to one another, at exactly the same stratigraphic horizon of the Slottsmøya member, strongly supporting the referral of PMO 214.136 to P. funkei.
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The number of traumatic events that led to these features is not certain, and it is possible that they were all caused by a single encounter, for example by crashing into a tree or rock during a fight with another animal, which may have caused puncture wounds with its claws. Since all the injuries had healed, it is certain that the Dilophosaurus survived for a long time after these events, for months, perhaps years. The use of the forelimbs for prey capture must have been compromised during the healing process. The dinosaur may therefore have endured a long period of fasting or subsisted on prey that was small enough for it to dispatch with the mouth and feet, or with one forelimb.
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Unfortunately, a positive response to forelimb flexion tests is one reason horses may be deemed unsuitable for purchase during the prepurchase exam. The wide range of significance attributed to these tests varies according to opinion and the experience of the examiner. While there have been many purchase exams discontinued solely because a positive response to a flexion test in one or both forelimbs, there’s really nothing in the veterinary literature to support such an action. Due to the variable response to the test depending on such things as the force applied, duration of the test, age of the horse and the day of examination, discontinuation of a prepurchase examination based solely on a failed forelimb flexion test is probably unwarranted.
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