A diagram of the anatomy of the maxillae in centipedes In centipedes, both pairs of maxillae are developed. The first maxillae are situated ventrally to the mandibles and obscure them from view. This pair consists of a basal plate formed from the fused coxae of each leg plus ventral sternite from this segment and is hence called a coxosternite and two pairs of conically jointed appendages called telopodites and coxal projections. The second maxillae, which partly cover the first maxillae, consist of only a telopodite and a coxosternite.
|
|
In this malacostracan crustacean diagram, the maxillae are labelled maxilla and maxillula. In arthropods, the maxillae (singular maxilla) are paired structures present on the head as mouthparts in members of the clade Mandibulata, used for tasting and manipulating food. Embryologically, the maxillae are derived from the 4th and 5th segment of the head and the maxillary palps; segmented appendages extending from the base of the maxilla represent the former leg of those respective segments. In most cases, two pairs of maxillae are present and in different arthropod groups the two pairs of maxillae have been variously modified.
|
|
The mandibles are pointed, while the maxillae end in flat, toothed "blades". To force these into the skin, the mosquito moves its head backwards and forwards. On one movement, the maxillae are moved as far forward as possible. On the opposite movement, the mandibles are pushed deeper into the skin by levering against the maxillae.
|
|
In crustaceans, the first pair are called maxillulae (singular maxillula). Modified coxae at the base of the pedipalps in spiders are also called "maxillae", although they are not homologous with mandibulate maxillae.
|
|
Much like expansion in the maxillae the dentaries expand transversely on the alveolar accommodate multiple rows of teeth. These 6 rows conical peg like teeth occur on medially expanded on both maxillae and dentaries.
|
|
Species in genus Leptochilichthys have toothless maxillae. The maxillae are considered especially long There are teeth on the palate and dentary. Many long gill rakers are also present. This genus does not exhibit any shoulder sac apparatus.
|
|
The preoral cavity so-formed contains paired mandibles and any maxillae which are present.
|
|
The labium is a single structure, although it is formed from two fused secondary maxillae. It can be described as the floor of the mouth and functioning in close the mouth of the insect. With the maxillae, it assists manipulation of food during mastication.
|
|
Insect head parts. Legend: a, antennae; c, compound eye; lb, labium; lr, labrum; md, mandibles; mx, maxillae. Insect anatomy A typical insect head possesses a pair of antennae; eyes; mandibles, labrum, maxillae and labium (the latter four forming the cluster of "mouth parts", no. 32. in the diagram).
|
|
The maxillae and labium are spinulose. It lacks a rastellum on the chelicerae. All tarsal scopulae are bisected longitudinally.
|
|
The labium is immediately posterior to the first maxillae and is formed from the fusion of the second maxillae, although in lower orders including the Archaeognatha (bristletails) and Thysanura (silverfish) the two maxillae are not completely fused. It consists of a basal submentum, which connects with the prementum through a narrow sclerite, the mentum. The labium forms the lower portion of the buccal cavity in insects. The prementum has a pair of labial palps laterally, and two broad soft lobes called the paraglossae medially.
|
|
Paired maxillae cut food and manipulate it during mastication. Maxillae can have hairs and "teeth" along their inner margins. At the outer margin, the galea is a cupped or scoop-like structure, which sits over the outer edge of the labium. They also have palps, which are used to sense the characteristics of potential foods.
|
|
In adult males, the tarsus of each palp is modified to carry an elaborate and often species- specific structure used for mating (variously called a palpal bulb, palpal organ or copulatory bulb). The basal segments of the pedipalps, the coxae, next to the mouth, are modified to assist with feeding, and are termed maxillae, although they are not homologous with the maxillae of mandibulate arthropods. In mesothele and mygalomorph spiders, the maxillae are only slightly modified; in araneomorph spiders, the anterior edge is often saw-like and is used in cutting up prey.
|
|
In non-chewing insects, such as adult Lepidoptera, the maxillae may be drastically adapted to other functions. Unlike the mandibles, but like the labium, the maxillae bear lateral palps on their stipites. These palps serve as organs of touch and taste in feeding and in the inspection of potential foods and/or prey. In chewing insects, adductor and abductor muscles extend from inside the cranium to within the bases of the stipites and cardines much as happens with the mandibles in feeding, and also in using the maxillae as tools.
|
|
In many hexapods, the mouthparts have been modified for different functions and the maxillae and labium can change in structure greatly. In bees, the maxillae and labium have been modified and fused to form a nectar-sucking proboscis. In the order Hemiptera, the true bugs, plant hoppers, etc., the mouthparts have been modified to form a beak for piercing.
|
|
Situated beneath the mandibles, paired maxillae manipulate food during mastication. Maxillae can have hairs and "teeth" along their inner margins. At the outer margin, the galea is a cupped or scoop-like structure, which sits over the outer edge of the labium. They also have palps, which are used to sense the characteristics of potential foods.
|
|
The labium typically is a roughly quadrilateral structure, formed by paired, fused secondary maxillae. It is the major component of the floor of the mouth. Typically, together with the maxillae, the labium assists manipulation of food during mastication. Dragonfly nymph feeding on fish that it has caught with its labium and snatched back to the other mouthparts for eating.
|
|
To some extent the maxillae are more mobile than the mandibles, and the galeae, laciniae, and palps also can move up and down somewhat, in the sagittal plane, both in feeding and in working, for example in nest building by mud-dauber wasps. Maxillae in most insects function partly like mandibles in feeding, but they are more mobile and less heavily sclerotised than mandibles, so they are more important in manipulating soft, liquid, or particulate food rather than cutting or crushing food such as material that requires the mandibles to cut or crush. Like the mandibles, maxillae are innervated by the subesophageal ganglia.
|
|
At the very anterior end of the rostrum they are fused. The maxillae are partially covered, and only a few maxillary teeth are at all visible, all smaller than the premaxillary teeth. They extend back, forming the posterolateral border of the naris and the lateral border of the orbit to just beyond the midpoint. A few striations are visible on the maxillae.
|
|
North American goniopholidids have maxillae and palatines that do not contact, resulting in a more open palate and a ventrally exposed bony nasopharyngeal passage.
|
|
A second branch of the hemipteroid lineage includes insects in which the haustellate mouthparts contain feeding stylets derived from both the mandibles and maxillae.
|
|
Crustaceans comprise a number of classes, with various feeding modes supported by a range of adaptions to the mouthparts. In general, however, crustaceans possess paired mandibles with opposing biting and grinding surfaces. The mandibles are followed by paired first and second maxillae. Both the mandibles and the maxillae have been variously modified in different crustacean groups for filter feeding with the use of setae.
|
|
The mouthparts are adapted to sucking and the mandibles are usually reduced in size or absent. The first maxillae are elongated into a tubular proboscis which is curled up at rest and expanded when needed to feed. The first and second maxillae bear palps which function as sensory organs. Some species have a reduced proboscis or maxillary palps and do not feed as adults.
|
|
The maxillae form needle-like structures, called stylets, which are enclosed by the labium. When mosquito bites, maxillae penetrate the skin and anchor the mouthparts, thus allowing other parts to be inserted. The sheath-like labium slides back, and the remaining mouthparts pass through its tip and into the tissue. Then, through the hypopharynx, the mosquito injects saliva, which contains anticoagulants to stop the blood from clotting.
|
|
The mouth is located behind the large upper lip, flanked by mandibles. The first pair of maxillae is very small, and the second pair has the same structure as the following thoracic legs: a large basal part, equipped with outgrowths on the inner side, used in locomotion, a forked inner branch and two outer lobes - referred to as the "pseudoepipod" and the "exopod". The structural and functional similarity between the maxillae and the legs may be a sign of primitive organization; the maxillae are not specialized, as they are in other crustaceans. The thorax consists of 10 segments, and the abdomen bears a telson but no other appendages.
|
|
In millipedes, the second maxillae have been lost, reducing the mouthparts to only the first maxillae which have fused together to form a gnathochilarium, acting as a lower lip to the buccal cavity and the mandibles which have been enlarged and specialized greatly, used for chewing food. The gnathochilarium is richly infused with chemosensory and tactile receptors along its edge.Hopkin, S. P. and Read, H. J. 1992. The Biology of Millipedes.
|
|
Females of different social standing can also be told apart based on morphology. Primary females are larger than secondary or tertiary females, and also have more mandibular and wing wear. X. virginica have distinctive maxillae that are adapted to performing perforations on corolla tubes to reach nectaries. Their maxillae are sharp and wedge-shaped, allowing them to split the side of corolla tubes externally to access the nectar.
|
|
Symphyla are small, cryptic myriapods without eyes and without pigment. The body is soft and generally long, divided into two body regions: head and trunk. An exceptional size is reached in Hanseniella magna, which attains lengths of . The head has long, segmented antennae, a postantennal organ, three pairs of mouthparts: mandibles, the long first maxillae, and the second pair of maxillae which are fused to form the lower lip or labium of the mouth.
|
|
Insects have a range of mouthparts suited to their mode of feeding. These include mandibles, maxillae and labium and can be modified into suitable appendages for chewing, cutting, piercing, sponging and sucking. Decapods have six pairs of mouth appendages, one pair of mandibles, two pairs of maxillae and three of maxillipeds. Sea urchins have a set of five sharp calcareous plates which are used as jaws and are known as Aristotle's lantern.
|
|
Termite antennae have a number of functions such as the sensing of touch, taste, odours (including pheromones), heat and vibration. The three basic segments of a termite antenna include a scape, a pedicel (typically shorter than the scape), and the flagellum (all segments beyond the scape and pedicel). The mouth parts contain a maxillae, a labium, and a set of mandibles. The maxillae and labium have palps that help termites sense food and handling.
|
|
The female mosquito does not insert its labium into the skin; it bends back into a bow when the mosquito begins to bite. The tip of the labium remains in contact with the skin of the victim, acting as a guide for the other mouthparts. In total, there are six mouthparts besides the labium: two mandibles, two maxillae, the hypopharynx, and the labrum. The mandibles and the maxillae are used for piercing the skin.
|
|
Eastern carpenter bees also have galae on their maxillae that are shaped like large, flat blades. Bees with sharp galae can use these to further aid in penetrating the corolla tubes.
|
|
H. psychedelicus has a blue metallic tinge to the cephalothorax and legs, and has scattered maxillary setae on the prolateral face of the maxillae. In other species it is "C" shaped.
|
|
Beside these, the orbits are where the eyes are situated. The mouthparts comprise three pairs of maxillipeds, behind which are a pair of maxillae, a pair of maxillules, and finally the mandibles.
|
|
The upper temporal fenestra is large and kidney-shaped. There are 17 cervical vertebrae and the cervical ribs have anterior processes. The maxillae of Dactylosaurus extended broadly up the side of the snout.
|
|
In crustaceans, the two pairs of maxillae are called maxillulae (1st pair) and maxillae (2nd pair). They serve to transport food to the mandibles but also frequently help in the filtration process and additionally they may sometimes play a role in cleaning and grooming. These structures show an incredible diversity throughout crustaceans but generally are very much flattened and leaf-like. The two pairs are normally positioned very close together and their apical parts generally are in direct contact with the mandible.
|
|
They also have the secondary palate that other primitive therapsids lacked, except the therocephalians, who were the closest relatives of cynodonts. (However, the secondary palate of cynodonts primarily comprises the maxillae and palatines as in mammals, whereas the secondary palate of the therocephalians primarily comprises the maxillae and the vomer.) The dentary was the largest bone in their lower jaw. The cynodonts probably had some form of warm-blooded metabolism. This has led to many reconstructions of cynodonts as having fur.
|
|
The labium forms a sheath around a set of stylets that consist of an outer pair of mandibles and an inner pair of maxillae. In lapping flies, a proboscis is formed from mostly the labium specialized for lapping up liquids. The labial palps form a labella which have sclerotized bands for directing liquid to a hypopharangeal stylet, through which the fly can imbibe liquids. In Lepidopterans, the fluid-sucking proboscis is formed entirely from the galea of the maxillae although labial palps are also present.
|
|
Up to the first three pairs of legs are modified to maxillipeds, which assist manipulation of food items by passing food forward to the mandibles for chewing or to the maxillae for cutting into smaller pieces.
|
|
Olin has long and projected chelicerae, and a relatively broad and low carapace, with the maxillae long and nearly parallel, with depressions laterally. There is little sexual dimorphism and no elongation on the fourth trochanter or coxae.
|
|
A small gap between the last premaxillary and first maxillary alveolus was probably where a large tooth from the mandible fitted in when the jaws were closed. The maxillae are large, although quite short, and had a very straight suture with the nasal but complex interdigitating sutures with other bones. They underlay the jugal next to the orbit, although this section was not actually preserved. There is little bony palate formed by the maxillae as their dental alveoli are very large, and so there is little space between them.
|
|
It is somewhat elongate, being about 28 centimeters (11 in) long but only an estimated 13 centimeters (5 in) at its widest. The maxillae, the main tooth-bearing bones of the upper jaw, had unusual elongate depressions on their sides, nine or ten per maxilla. Other skull bones had heavily textured surfaces, as is seen on other crocodyliforms. The premaxillae at the tip of the snout had five teeth each, and the maxillae 16 or 17, with wide spacing; because the jaws are closed, the teeth of the lower jaw cannot be observed.
|
|
In mandibulate mouthparts, the labium is a quadrupedal structure, although it is formed from two fused secondary maxillae. It can be described as the floor of the mouth. With the maxillae, it assists with manipulation of food during mastication or chewing or, in the unusual case of the dragonfly nymph, extends out to snatch prey back to the head, where the mandibles can eat it. The labium is similar in structure to the maxilla, but with the appendages of the two sides fused by the midline, so they come to form a median plate.
|
|
These maxillae were mostly worn around the arm, generally on the biceps of soldiers. This was seen as a testament of strength and power that proved that these individuals had been in multiple battles or campaigns. Along with the maxillae, the men had necklaces made of teeth, obsidian projectile points and slate disks located behind their lower back, which were commonly found on Teotihuacan military figures. This led the excavators to believe that these soldiers were of an elite class of warrior, and not just some semi-organized militia.
|
|
The nasal chambers had two openings, including the choanae (internal nostrils), and the air passage was looped. The maxillae expanded to the sides, giving the impression of a bulge, which may have been due to the sinuses inside. The maxillae had a ridge that may have been the attachment site for fleshy cheeks; the presence of cheeks in ornithischians is controversial, but some nodosaurs had armor plates that covered the cheek region, which may have been embedded in the flesh. Specimen AMNH 5214 has 34–35 dental alveoli (tooth sockets) in the maxilla.
|
|
The second antenna is strongly reduced in females, and consists of numerous segments in males. Cumaceans have six pairs of mouthparts: one pair of mandibles, one pair of maxillules, one pair of maxillae and three pairs of maxillipeds.
|
|
It lacks eyes. Its mandibles are rod-like, with anterior dentition. Its maxillae has 7 pairs of free denticles. It also counts with two peristomial segments without setae, its parapodia being uniramous and showing short dorsal and ventral cirri.
|
|
Sason robustum is characterized by absence of teeth on the claws; cuspules present on maxillae and labium; rastellum absent; the apex of the first tibia with a single stout prolateral spine; and the palpal bulb spherical with a tapering embolus.
|
|
O. philippinus is orange in colour. It is 28 mm long, or 30 mm with chelicerae included. The fovea is procurved. The retrolateral face of the chelicerae is setae-less and the stridulatory setae on the maxillae are butter knife-shaped.
|
|
Mouthparts show little development, with only mandibles and maxillipeds present, sometimes with a second pair of rudimentary maxillae. Males are of smaller size than females and of different appearance. Development is through regressive metamorphosis, undergoing two or three larval stages.
|
|
At least eleven dental alveoli were present, although the total is not certain as both maxillae are broken off at the posterior ends. Small replacement teeth are visible above some of the alveoli, indicating it was probably a polyphyodont. The premaxillae are very similar to those of Postosuchus, but slightly smaller; the posterodorsal process is broken off, but sutures present on the nasal bones show it would have extended all the way up to the anterior border of the naris. The palatal processes of the premaxillae are incompletely preserved, but would almost certainly have articulated with those of the maxillae.
|
|
The preserved maxillae have length of about twelve centimetres. This indicates that Maleevus was a medium-sized ankylosaur of around . The height and weight of Maleevus is unknown due to the lack of known remains. (size estimates based on the related Talarurus).
|
|
The alveolar borders of the maxillae were eroded and no teeth were preserved. The recovered fossil material ranges from red to grey, but the coloration is not thought to bear any taphonomic significance, and the variation most likely arose from differential weathering.
|
|
Meyrick described this species as follows: Alfred Philpott studied the maxillae parts of lepidoptera including this species and stated that the genus to which this species belongs had palp that were three or four segmented and were smaller than other genera studied.
|
|
This species resembles O. puerilis in jaw morphology. O. eutrophila is dimorphic, with males being than females, while possessing K-type maxillae. Ophryotrocha eutrophila, however, differs from O. puerilis in the absence of eyes and the presence of a developed median pygidial stylus.
|
|
The prostomium has two short frontal antennae, two globular palps and five main antennae. The mandibles are large and the maxillae have several pairs of plates edged with fine teeth. Some tentacular cirri are present. The anterior parapodium points forward and has tapered ventral cirri.
|
|
The larvae, although preferring damp habitats near water, are non- aquatic and tend to drown easily. They have a distinct labrum and well developed galea of maxillae. 9th abdominal tergum has a pair of apical, re- curved ventral hook and 2-segmented urogomphi.Hydraenidae, Lucid Central.
|
|
The chelicerae are creamy colored. All four leg pairs are identical. The femur is blackish brown with a cream band, the patella is creamy and the tibia have two parallel lines of oblong spots. Ventrally the body is pale brownish with much darker maxillae.
|
|
It possesses no eyes, its mandibles being L-shaped, counting with anterior serration. Its maxillae exhibits 7 free denticles. It also counts with two peristomial segments without setae. Its parapodia has dorsal ventral cirri, with simple supraacicular chaetae and compound subacicular chaetae with serrated blades.
|
|
Mesocetus is similar to other tranatocetids in having rostral bones that override the frontals and contact the parietals, nasals dividing the maxillae on the vertex, a dorsoventrally bent occipital shield with a more horizontal anterior portion and more vertical posterior portion, and a tympanic bulla with short, narrow anterior portion with rounded or squared anterior end and wider and higher posterior portion that is particularly swollen in the posteroventral area. Shared characters with Tranatocetus include posterior ends of premaxillae fused with the maxillae and divided on the vertex by long, narrow and high (vertical plate-like) nasals and cervical vertebrae with wide transverse foramina, almost as wide as the centra.
|
|
It is widely agreed that the insect, myriapod and crustacean heads are very similar. The apparent lack of a second antenna in insects and myriapods is explained by the idea that this appendage has been lost, leaving an appendage-less segment known as the intercalary segment. Modern phylogenies do not in general support an insect-myriapod relationship, suggesting that the second antenna has been lost independently in each group, perhaps as a result of a convergent adaptation to life on land. Furthermore, there is general agreement that the mandibles, first maxillae and labium/second maxillae each represent a post-oral segment; and that the first antenna represents a preoral segment.
|
|
The golden mole thrusts its forearms from under its body to help it burrow deeper into the earth. Both the male and female have a cloaca. They have tabulars in the occipital which is not found in other mammals. Their zygomatic arches form elongations of the maxillae.
|
|
Mouthparts can have multiple functions. Some insects combine piercing parts along with sponging ones which are then used to pierce through tissues of plants and animals. Female mosquitoes feed on blood (hemophagous) making them disease vectors. The mosquito mouthparts consist of the proboscis, paired mandibles and maxillae.
|
|
The sternum (chest) is brownish black, with a yellow central area. The chelicerae (fangs) are black with four to six small teeth. The maxillae and other mouthparts are black at the base, lightening to brown and bright yellow at the tips. The pedipalps are dark brown.
|
|
The telopodite is recognizably leglike in structure and consists of three segments plus an apical claw. The second maxillae also have a metameric pore, which is the opening of the maxillary gland and maxillary nephridium homologous to those of millipedes.Lewis, J. G. E. 1981. The Biology of Centipedes.
|
|
Adephagans have simple antennae with no pectination or clubs. The galeae of the maxillae usually consist of two segments. Adult adephagans have visible notopleural sutures. The first visible abdominal sternum is completely separated by the hind coxae, which is one of the most easily recognizable traits of adephagans.
|
|
Diplura is a genus of South American curtain web spiders that was first described by C. L. Koch in 1850. It is found in South America and Cuba belonging to the subfamily Diplurinae. They possess a lyra on their prolateral maxillae. Diplura species can be distinguished from Trechona sp.
|
|
The female of the species has a total length of ; a cephalothorax length of , and a width of . Its labium length is 45% of its width; its sternum width is 66% of the length. Its labium possesses two cuspules, while the maxillae has six cuspules. A serrula is absent.
|
|
Ozopactus is a monotypic genus of Venezuelan tarantulas containing the single species, Ozopactus ernsti. It was first described by Eugène Louis Simon in 1889, and is found in Venezuela. They have an enlarged sternum and an enlarged maxillae. The front of the ocularium is no longer than the back.
|
|
The opposing surfaces bear strong brownish teeth. As the crustacean periodically opens and closes the mandibles the teeth move apart and close together. Of the usual crustacean head appendages, only the mandibles are well developed. In Triops longicaudatus, the larger second maxillae are absent, only maxillules being present.
|
|
The tooth rows of the upper jaws are inset while the maxillae and zygomatic arches extend outward, suggesting that traversodonts may have had cheeks. Primitive features of traversodonts include costal plates around the vertebrae, which stabilize the spine. These plates were lost in more advanced traversodonts like Exaeretodon.
|
|
The maxilla (plural: maxillae )OED 2nd edition, 1989. in vertebrates is the upper fixed (not fixed in Neopterygii) bone of the jaw formed from the fusion of two maxillary bones. In humans, the upper jaw includes the hard palate in the front of the mouth.Merriam-Webster Online Dictionary.
|
|
In addition, the surface characteristics of the labial side of the dentaries are similar to those of the maxillae, showing little sculpturing, and occasional small foramina. A well-developed, anteriorly extending Meckelian canal is formed by the dentary bone, below which it would be attached to the splenial by sutures.
|
|
The antennae are yellow with a darkened base. The head is yellow, the crown of the head being black and ending with reddish-brown stripes. The maxillae are reddish-brown, outlined in black. The thorax is yellow, the dorsal part black, but with a quartet of dark reddish- brown spots.
|
|
The lobster's head bears antennae, antennules, mandibles, the first and second maxillae. The head also bears the (usually stalked) compound eyes. Because lobsters live in murky environments at the bottom of the ocean, they mostly use their antennae as sensors. The lobster eye has a reflective structure above a convex retina.
|
|
Its unique stridulating organ consists of a long scopula surrounded by plumose setae on the retrolateral side of the chelicerae. It can be further distinguished by the a transverse fovea, multiple lobes on the maxillae and labium, a long distal segment of spinnerets, and the lack of a prolateral cheliceral scopula.
|
|
In other odontocetes, parts of the frontal and maxillae cover the temporal fossae. In Odobenocetops, these bones are reduced and narrowed so that the temporal fossae is open dorsally. The periotic and tympanic bones are similar to those in other dolphins. No mandible has been recovered and only few postcranial elements.
|
|
A spine is present on the upper side of the tip. Sound-producing ridges on the chelicerae (stridulatory organs) are absent in females but present in males. The chewing appendages (maxillae) are located immediately behind the chelicerae. They are strongly curved on the outside edges and tapers into a blunt tip.
|
|
A mosquito biting a human finger In female mosquitoes, all mouthparts are elongated. The labium encloses all other mouthparts like a sheath. The labrum forms the main feeding tube, through which blood is sucked. Paired mandibles and maxillae are present, together forming the stylet, which is used to pierce an animal's skin.
|
|
Behind this expansion, the upper jaw had a notch bearing significantly smaller teeth, into which the also expanded tips of the dentaries (tooth bearing bones of the mandible) fit into, with a notch behind the expansion of the dentary. The maxillae (main upper jaw bones) were long and formed a low branch under the nostrils that connected to the rear of the premaxillae. The teeth at the frontmost part of the maxillae were small, becoming significantly larger soon after and then gradually decreasing in size towards the back of the jaw. left Lengthwise atop their skulls ran a thin and shallow sagittal crest that was usually tallest near or above the eyes, either becoming shorter or disappearing entirely towards the front of the head.
|
|
Such traits include the presence of a sagittal crest on parietal bone, maxillae and dentaries that are expanded from the middle to the sides, and with teeth present on both the occlusal and lingual surfaces. However, unlike rhynchosaurids, but like both Howesia and Mesosuchus, Eohyosaurus lacks a longitudinal occlusal groove and an occlusal blade on its maxillae and dentaries, respectively. Like in Rhynchosauridae and possibly Howesia (but not Mesosuchus), the occlusal margin of its maxilla is offset to the bottom from the lower margin of the main body of the jugal bone. Unlike rhynchosaurids that possess a short anguli oris crest on the jugal, in Eohyosaurus it is present on the side surface of the maxilla, while Mesosuchus lacks it entirely and it is unknown in Howesia.
|
|
A brain endocast of P. transouralicum shows it was only 8 percent of the skull length, while the brain of the Indian rhinoceros is 17.7 percent of its skull length. Upper molars of P. transouralicum, Musee d'Histoire Naturelle, Paris The species of Paraceratherium are mainly discernible through skull characteristics. P. bugtiense had features such as relatively slender maxillae and premaxillae, shallow skull roofs, mastoid-paroccipital processes that were relatively thin and placed back on the skull, a lambdoid crest, which extended less back, and an occipital condyle with a horizontal orientation, which it shared with Dzungariotherium. P. transouralicum had robust maxillae and premaxillae, upturned zygomata, domed frontal bones, thick mastoid-paroccipital processes, a lambdoid crest that extended back, and occipital condyles with a vertical orientation.
|
|
These lice chew on their hosts, which means that they have mandibles for feeding. They do, however, lack the maxillae that are common to most insects that chew their food. These lice have spiracles located on the edges of each segment of the abdomen to allow the lice to breathe.Wikivet. Bovicola bovis – WikiVet en.Wikivet.
|
|
Members of Catumiri have a labium that is much wider than long, and also houses few cuspules along with the maxillae. The anterior scopula is divided by setae, and the spermathecae of females only have one lobe/terminus. There is a row of spines on the prolateral region of the tarsal claw of males.
|
|
They still have grooved maxillae and their tentoriolacinial muscle does not attach to the mesal stipial base. Their larvae, like those of predaceous diving beetles, do not possess eggshell-bursters on the head. It is not yet resolved whether Haliplidae and Dytiscidae are closest relatives, or whether they originated independently from the basal Adephaga.
|
|
Restoration The holotype, cataloged as MTM V2009.192.1. It consists only of a few skull fragments, including rostral bones, fused premaxillae, and maxillae fragments (the beak and jaw fragments). These fossils are kept in the Hungarian Natural History Museum, in Budapest. Although the fossils are fragmentary, the paper describing Ajkaceratops estimated a body length of .
|
|
For instance, maxillary lateral incisors originate where the lateral maxillae and medial nasal bone processes fuse. In contrast, Kjaer et al. (1994) suggested regions where innervation developed were more sensitive than areas of fusion. Commonly affected regions were found to undergo innervation last, this might imply the developmental relationship between nerve and hard tissue.
|
|
With the exception of some barnacles, maxillopodans are mostly small, including the smallest known arthropod, Stygotantulus stocki. They often have short bodies, with the abdomen reduced in size, and generally lacking any appendages. This may have arisen through paedomorphosis. Apart from barnacles, which use their legs for filter feeding, most maxillopodans feed with their maxillae.
|
|
Notwithstanding this treatment does not scope the disease itself. Actually, it is the repositioning of bone from calvaria to the maxillary bones, and placement of dental implants in a completely edentulous maxilla when the patient has already lost all teeth. An already developed method to reconstruct maxillae in edentulous elderly people by other dental professionals.
|
|
ODAN-A-19 (or ODAN-Amf-8), -20, and -21, all incomplete maxillae. The frontal bones belong to three different size classes, with -15 being largest, -16 and -17 being intermediate, and -23 being smallest. In 2017, Oardasaurus was named as a new genus by Vlad Codrea, Márton Venczel, and Alexandru Solomon in a research paper.
|
|
The occipital condyle, the contact with the neck, is obliquely pointing to below, an ankylosaurid trait causing the head to be pointing downwards. The beak is toothless. The tooth rows of the maxillae are rather straight and each consist of fifteen to sixteen small teeth, lacking a true cingulum, swollen basis. There is no armour on the snout.
|
|
They had smooth cutting surfaces, and, unlike those of other therocephalians, lacked facets or striae resulting from abrasion and wear. The large saber-like canines are held within the maxillae, and are quickly identifiable features of Moschorhinus. They are especially thick and strong, and uniquely circular in cross-section. In length, these sabers are comparable to gorgonopsids.
|
|
The symphysis has a low keel at the underside. The palate is well-preserved and seems to show that the traditional interpretation of its bones is the correct one, contra the more modern view that what have usually been seen as the fronts of the palatine bones would really be the internal wings of the maxillae.
|
|
Based on comparisons with Irritators relatives, the maxillae were probably lined with a total of 11 teeth each, similar to the number of 12 teeth in MSNM V4047, an upper jaw fossil referred to Spinosaurus. The hindmost tooth of the Irritator specimen's left maxilla was not yet fully erupted, and only the tip of it was visible.
|
|
The palate is only lightly constricted in top view and the typical ankylosaurian hourglass profile is largely lacking. The same is true for the curvature of the tooth rows in the maxillae. There are twenty- two to twenty-five maxillary teeth per side. The last six teeth in the rear are conspicuously larger than the front teeth.
|
|
It had slender, forked premaxillae that turned up and expanded in the front, creating a shovel-like structure. Desmatosuchus is unique among aetosaurs in that its species are the only known aetosaurs that lacked teeth on their premaxillae. Their premaxillae fit loosely together with their maxillae, indicating flexibility at that joint. Their maxilla contained 10 to 12 teeth.
|
|
The teeth are restricted to the front half of the maxillae in Parringtonia and Erpetosuchus, and the back of the maxilla is thicker than it is tall. Parringtonia has five tooth sockets, Erpetosuchus granti only four, and Erpetosuchus sp. six or more. Unlike Erpetosuchus, Parringtonia has a foramen or hole on the outer surface of the maxilla.
|
|
The maxillae, the upper jaws, were long and contained about eighteen small teeth on each side. The outside of the maxilla was covered by a large loreal osteoderm, overlapping the snout edge. A large lacrimal plate is present behind it. The rim above the eye socket has two osteoderms, each forming a separate peak as with Asian ankylosaurids.
|
|
The specific descriptor deinosauriscus, "little dinosaur", alludes to the animal's small size for a dinosaur. The holotype, ZPAL MgD-II/29, was discovered in Late Cretaceous river sandstones of the Djadokhta Formation beds, dating from the late Campanian. It consists of an articulated but fragmentary skull and lower jaws comprehending paired maxillae, a partial jugal, palate bones and dentaries.
|
|
The hypopharynx is a somewhat globular structure, located medially to the mandibles and the maxillae. In many species it is membranous and associated with salivary glands. It assists in swallowing the food. The hypopharynx divides the oral cavity into two parts: the cibarium or dorsal food pouch and ventral salivarium into which the salivary duct opens.
|
|
Relative lengths, 4, 1, 2, 3. Palpi concolorous, moderately long, armed with a few rather long spines. Falces yellow, short, arched, not strong; inferior ridge of each falx armed with two very small teeth, and the superior with two even smaller ones; fang short, weak. Maxillae short, robust, arched, yellow, apices inclined inwards, constricted near base.
|
|
The bowfin skull is made up of 28 fused bones, which compose the dermatocranium. The roof of the mouth is made up of 3 bones, the ectopterygoid, the palantine, and the vomer. The teeth are on two bones, the premaxillae and the maxillae. Another three bones make up the lower jaw the dentary, the angular, and the surangular.
|
|
Sophineta is known from holotype ZPAL RV/175, a nearly complete right maxilla. Many specimens are referred to the species and represent frontals, parietals, prefrontal, postfrontals, postorbitals, jugals, squamosals, pterygoids, quadrates, maxillae, premaxilla, dentaries, vertebrae and ilia. Skull fragments and vertebral column were associated. All specimens are housed in the Institute of Paleobiology, Polish Academy of Sciences, Warsaw.
|
|
Cryonectes is characterized by a unique combination of characters including a very slight constriction between premaxillae and maxillae, its snout is greatly elongated and the mandible has a long symphysis bearing seven tooth position and retaining a ventral mandibular ridge. A cladistic analysis performed by Peggy Vincent, Nathalie Bardet and Emanuela Mattioli found it to be basal to Pliosaurus, Peloneustes and other pliosaurids.
|
|
The mouthparts of these insects are adapted for predation. There are toothed stylets on the mandibles able to cut into and abrade tissues of their prey. There are further stylets on the maxillae, adapted as tubular canals to inject saliva and to extract the pre-digested and liquified contents of the prey. Some species attack pest insects and are used in biological control.
|
|
Oxford University Press Print, 3,??-??. The other four legs are slightly flattened and used for swimming. The mouth parts consist of a stout syringe-like rostrum or beak and long piercing stylets that were once mandibles and maxillae. They also have retractable strap-like appendages that allow for snorkeling while under water which are located on the posterier end of the abdomen.
|
|
The conglomerate is interpreted as debris flows along a lake margin. Redondavenator was named in 2005 by Sterling Nesbitt and colleagues. The type species is R. quayensis, referring to Quay County. The preserved portion of the skull includes the premaxillae (snout tip) and parts of the maxillae (main tooth-bearing bones of the upper jaw) and nasals, in front of the antorbital fenestra.
|
|
While there is no real modern analogue, the most similar living example would be the clouded leopard (Neofelis nebulosa). Like other therocephalians, Moschorhinus had a reduced number of molars which were housed in the maxillae. In most therocephalians, the “teeth,” or rather toothlike projection (denticulations) of the pterygoid bones, are greatly reduced or missing, and in Moschorhinus they are absent.
|
|
They have from four to six pairs of feathery limbs, or "cirri", which they project out of their borings to catch drifting detritus for food. The mouthparts consist of mandibles, maxillules and maxillae. One pair of cirri is close to these while the others are at the other end of the body. Each individual acrothoracican is either male or female.
|
|
The dorsal margin of the maxilla is unusually concave unlike the convex condition in tyrannosaurids. The nares are large and elliptical, supporting its relation to proceratosauridae. The dentary gradually curves upwards as it approaches its front edge. Many teeth are preserved attached to the maxillae, with a roughly equal number of denticles on each side, similarly to those of tyrannosaurids.
|
|
They are active under direct sunshine and hours when the temperature is above 22 °C (71.6°). When feeding, the females use scissor-like mandibles and maxillae to make a cross-shaped incision and then lap up the blood. Their bite can be painful. Anti-coagulants in the saliva of the fly prevents blood from clotting and may cause severe allergic reactions.
|
|
Yang originally assigned it to its own family (Edentosuchidae) within Protosuchia, but later research by Diego Pol and colleagues using the new material found it to be a protosuchid. Edentosuchus had markedly heterodont teeth. In the upper jaw, the teeth in the tip of the snout (premaxillae) were conical. Following them, the first two teeth of the maxillae had three cusps.
|
|
Qianosuchus had a skull around 33 cm (13 inches) long, with an elongated snout. The rostrum formed by the premaxilla is shallow at the front of the skull but deepens posteriorly. Each premaxilla has nine long teeth, and the maxillae bear eighteen teeth each. All the teeth are laterally compressed, curved backwards and serrated, like those of most other carnivorous archosaurs.
|
|
Size compared to a human The holotype, and only known specimen, is fragmentary. From the skull are preserved both maxillae, premaxillae, nasals, prefrontals, palatines and quadrates, the left jugal, the right pterygoid, quadratojugal, surangular, articular, squamosal and lacrimal, and fragments of the dentary. There are also the first three cervical vertebrae, nine caudal vertebrae, some caudal scutes and fragments of cervical ribs.
|
|
Most members of the second thalattosaur group, Thalattosauroidea, have more distinctive downturned snouts. Clarazia and Thalattosaurus both have snouts that taper into a narrow tip. Most of the snout is straight, but premaxillae at the tip are downturned. Xinpusaurus and Concavispina also have downturned premaxillae, but the end of the maxillae are sharply upturned, forming a notch in their skull.
|
|
Morphology, radio-tomographic study, and biomechanic considerations]. Paleontologia i Evolució 26-27:121-131. [Spanish] Additional material from the type locality was collected in 1994 - including two maxillae, two dorsal vertebrae, a complete sacrum, two fragmentary ribs, and a partial ischium. The species name was corrected to isonensis in 1997 by Laurent et al..Laurent, Y., LeLoeuff, J., & Buffetaut, E. (1997).
|
|
The trophi, or mouthparts of a locust, a typical chewing insect: 1 Labrum 2 Mandibles; 3 Maxillae 4 Labium 5 Hypopharynx Examples of chewing insects include dragonflies, grasshoppers and beetles. Some insects do not have chewing mouthparts as adults but do chew solid food when they feed while they still are larvae. The moths and butterflies are major examples of such adaptations.
|
|
The palate (roof of the mouth) also possesses teeth. The palatine bones, positioned right next to the maxillae, possess a fair number of teeth. The most notable assortment of palatal teeth are a bundle of large fangs preserved midway down the skull. Large palatal fangs are also shared by Sparodus, explaining how Boii crassidens was once considered to be part of that genus.
|
|
The eyes are close together and more or less equally spaced. The grooves in which the fangs of the chelicerae rest have two teeth on the outer margin and one on the inner margin. The male's maxillae each have an outgrowth (apophysis) that is absent in females. Accurate identification depends on the shape of the male palpal bulb and the female epigyne.
|
|
Amphionides grows to a length of . Morphologically, Amphionides is somewhat unusual, with many body parts being reduced or absent. For example, it has only one pair of mouthparts – the maxillae – the mandibles and maxillules being vestigial. Males and females differ in the form of the antennae, and also by the presence in males of the eighth thoracic appendage, albeit in a reduced form.
|
|
Sason hirsutum was first described by Peter J. Schwendinger in 2003. The species name, hirsutum, meaning "hairy", refers to the long dense hair on the legs. The male is similar to S. andamanicum, but can be distinguished by a number of features, including the short, stout cuspules on the labium and maxillae, and the thinner, straight embolus of the palpal bulb.
|
|
Its maxillae have seven pairs of free denticles. It counts with two peristomial segments without setae. It counts with a cirriform acicular lobe, its supraacicular chaetae being simple, while the subacicular chaetae are compound, and exhibit serrated blades. Its pygidium has a terminal anus, with two pygidial cirri that measure as long as its antennae and shows a short appendage ventrally.
|
|
The maxillae do not slip back because the toothed blades grip the skin. The hypopharynx and the labrum are both hollow. Saliva with anticoagulant is pumped down the hypopharynx to prevent clotting, and blood is drawn up the labrum. To understand the mosquito mouthparts, it is helpful to draw a comparison with an insect that chews food, such as a dragonfly.
|
|
The maxillae contained replacement teeth that had rugose enamel, similar to Camarasaurus, but lacked the small denticles (serrations) along the edges. Since the maxilla was wider than that of Camarasaurus, Brachiosaurus would have had larger teeth. The replacement teeth in the premaxilla had crinkled enamel, and the most complete of these teeth did not have denticles. It was somewhat spatulate (spoon-shaped), and had a longitudinal ridge.
|
|
Teeth were present only in the maxillae (upper cheeks) and dentaries (main bone of the lower jaw). The teeth were continually replaced, taking about half a year to form. They were composed of six types of tissues, rivaling the complexity of mammal teeth. They grew in columns, with an observed maximum of six in each, and the number of columns varied based on the animal's size.
|
|
Ostracods typically have no gills, instead taking in oxygen through branchial plates on the body surface. Most ostracods have no heart or circulatory system, and blood simply circulates between the valves of the shell. Nitrogenous waste is excreted through glands on the maxillae, antennae, or both. The primary sense of ostracods is likely touch, as they have several sensitive hairs on their bodies and appendages.
|
|
The family Elapidae is distinguished from other snake families by their proteroglyphous dentition. They have at least one pair of fangs that are hollow and fixed i.e. immobile at the front of the mouth, specifically located on the rostral area of the maxillae. This fang structure is designed to deliver toxins, which is why elapid snakes around the world are notoriously known as the most venomous.
|
|
On its top is a low crest, two to three millimetres high. The nares are long, slit-like and positioned above and in front of the large skull openings, the fenestrae antorbitales, with which they are not confluent. Of the jaws, which are very straight, the front part is lacking. There are six pairs of teeth in the maxillae and three pairs in the praemaxillae.
|
|
The teeth on the premaxillae (bones at the very tip of the upper jaw) were slender, unlike those of the maxillae (the main tooth-bearing bones in the upper jaw) which had a straight posterior edge.Gower (1999), pp. 37–38. The upper jaw bore 30 teeth, with each premaxilla carrying about 4 teeth and each maxilla 11, while the lower jaw held 22 teeth.
|
|
The maxillae are tall and laterally compressed, forming most of the borders of the antorbital fenestra (visible on the photo above). The palatal process extends anteroventrally and is very short. A ridge extending to form a suture with the palatine is present above the sixth, seventh and eighth dental alveoli. Small infraorbital foramina are located around the edge of the antorbital fenestra, near the teeth.
|
|
The developmental disturbance of anodontia (or hypodontia, if only one tooth), in which tooth germs are congenitally absent, may affect the development of the alveolar processes. This occurrence can prevent the alveolar processes of either the maxillae or the mandible from developing. Proper development is impossible because the alveolar unit of each dental arch must form in response to the tooth germs in the area.
|
|
Skull material for Mandasuchus is limited to maxillae and part of a dentary. The maxilla is low, with an elongated antorbital fenestra and at least 12 tooth sockets separated by discrete interdental plates. The antorbital fenestra is surrounded by an inset basin, the antorbital fossa, as with other archosaurs. However, Mandasuchus has a restricted and weakly differentiated antorbital fossa compared to other loricatans and Ticinosuchus.
|
|
This was due to the shared presence of 'rear forking' at the posterior end of the maxillae, only nine maxillary teeth, and the similarity between their right pterygoid bones. In 2016, M. Belén von Baczko and M. Ezcurra reassessed this synonymization and found that Dasygnathoides was in fact a much larger and quite different species to Ornithosuchus, and not even an ornithosuchid (see above).
|
|
At this excavation site in Mexico, archaeologists found roughly 72 males. Due to the evidence surrounding them they were determined to be soldiers. The individuals were placed in a series of highly structured graves that were below, and just outside, the pyramid. From the other evidence unearthed, it was found that each individual had between 7 and 11 human maxillae, or human jaw bones, in his possession.
|
|
Richardson's snaggletooth is a slender, laterally-compressed fish with a short snout, a terminal, horizontal mouth and large fang-like teeth. The teeth on the maxillae are backwards-pointing and comb-like. The long barbel on the chin is ribbon-like and lacks a bulb or swelling at its tip. The dorsal fin has 12 to 14 soft rays and the anal fin has 13 to 18.
|
|
Members of this genus are usually larger than those in Psiloderces and Merizocera, but can also be distinguished by teeth on the retromargin of the chelicerae (behind the fang), a round maxillae, and a longer labium. They can be distinguished from Althepus by the rounded posterior margin of the carapace and a shallow fovea that doesn't quite reach the posterior thoracic margin, among other factors.
|
|
Skull of the holotype specimen Tranatocetus is similar to "Aulocetus" latus, "Cetotherium" megalophysum, "Cetotherium" vandelli, Mesocetus, and Mixocetus in having rostral bones that override the frontals and contact the parietals, nasals dividing the maxillae on the vertex, a dorsoventrally bent occipital shield with a more horizontal anterior portion and more vertical posterior portion, and a tympanic bulla with short, narrow anterior portion with rounded or squared anterior end and wider and higher posterior portion that is particularly swollen in the posteroventral area. Like other tranatocetids, the skull vertex of Tranatocetus is X-shaped in dorsal view. However, Tranatocetus differs in having a wide skull with laterally expanded squamosals, straight ascending processes of maxillae which extend parallel to each other (rather than tapering and converging posteriorly), small lateral projection of the posterior meatal crest on the posterolateral side of the postglenoid process and paroccipital processes extending far posterior to the occipital condyles.
|
|
Lachrymal glands located behind each eye allow the loggerhead to maintain osmotic balance by eliminating the excess salt obtained from ingesting ocean water. On land, the excretion of excess salt gives the false impression that the turtle is crying. The urea content is high in Caretta caretta tears. The skull is most easily distinguished from other sea turtles by having maxillae that meet in the mid- line of the palate.
|
|
Juveniles have six pairs of legs, but over a lifetime of several years, they add an additional pair at each moult so an adult instar has twelve pairs of legs. Symphylans lack eyes. Their long antennae serve as sense organs. They have several features linking them to early insects, such as a labium (fused second maxillae), an identical number of head segments and certain features of their legs.
|
|
The body is elongated and cylindrical, with a postanal telson at the end. The mouthparts are entognathous (enclosed within the head capsule) and consist of thin mandibles and maxillae. There are no cerci at the end of the abdomen, which gives the group their name, from the Greek proto- (meaning "first", in this case implying primitive), and ura, meaning "tail". The first three abdominal segments bear limb-like appendages called "styli".
|
|
Numerous white or pale blue scales cover the clypeus ("face") and chelicerae. This covering extends around the sides of the carapace, ending beyond the posterior median eyes. In males, the labium is two-fifths as long as the maxillae, and as wide as it is long. The chelicerae of males are greatly enlarged and obliquely oriented, with each chelicera having a prominent inner tooth and a long, curved fang.
|
|
Radiocarbon and luminescence dating of the sediments established a minimum age of 51,000 to 46,000 years, and direct uranium-thorium dating of the fossils indicated a maximum age of 63,000 years. TPL1 includes the frontal, partial occipital, right parietal, and temporal bone, as well as the right and left maxillae and a largely complete dentition. It was identified as belonging to an anatomically modern human with distinct Sub-Saharan African features.
|
|
Many skull bones are also crushed and distorted, and some such as the maxillae ("mx"), nasal bones ("ns"), and sclerotic rings ("scl") are displaced. Part of the underside of the skull roof (perhaps the frontals, "?fr") can be seen among the bones of the lower jaws, palate (palatine bone, "pl" + pterygoid, "pt"), and braincase (parasphenoid, "ps" + basipterygoids, "bpt"). Twenty-one small teeth are preserved splaying out from the jaws.
|
|
Branchiurans are composed of an oval carapace, four pairs of swimming legs, a pair of anterior compound eyes, and an unsegmented abdomen. They are also compressed dorsoventrally and can be between two and thirty millimeters in length. In the genera Argulus, Chonopeltis, and Dipteropeltis, the adults have a pair of suction cups that are from modified first maxillae. The genus Dolops, keeps the larval stages claw-like appendages into adulthood.
|
|
The first and second preserved maxillary teeth were the largest, at and in crown length. The seven remaining teeth became progressively smaller towards the rear, one of the last ones measuring in estimated crown length. CT scans performed on the specimen revealed replacement teeth on both sides of the upper jaw. Their roots ran deep into the maxillae and converged close to the midline, nearly reaching the top of the skull.
|
|
Two pairs of well- developed antennae are used to swim through the water. In addition, there is a pair of mandibles and two pairs of maxillae. The thorax typically has two pairs of appendages, but these are reduced to a single pair, or entirely absent, in many species. The two "rami", or projections, from the tip of the tail, point downwards and slightly forward from the rear of the shell.
|
|
X. virginica survive mostly on nectar and pollen. Newly emerged bees do not have food stored in their nest, but they are occasionally brought nectar. X. virginica use their maxillae to penetrate the corolla of plants and reach the nectar stores, a behavior known as nectar robbing. This happens when the bee pierces the corollas of long-tubed flowers, thus accessing nectar without making contact with the anthers and bypassing pollination.
|
|
Meridiosaurus is an extinct genus of mesoeucrocodylian that is a possible member of the family Pholidosauridae.Page 135; Origins and evolution of the Antarctic biota By J. Alistair Crame, Geological Society of London, 1989. / Remains have been found in the Late Jurassic Tacuarembó Formation in Tacuarembó, Uruguay. The genus was described in 1980 on the basis of a partial rostrum that included the premaxillae and most of the maxillae.
|
|
The Australian herring has a streamlined, moderately deep and slightly elongate body which is somewhat compressed and has a relatively thin caudal peduncle. It has a quite small head with rather large eyes and a moderately large oblique mouth with the maxillae extending as far as thelevel of the centre of eyes. It has a narrow band of small, pointed teeth on each jaw. It has an almost straight lateral line.
|
|
The only described material of A. laaroussii are dentaries, maxillae, a premaxilla and several teeth. They broadly resemble A. madagaskarensis in general form but with a few distinguishing differences. The tooth count of A. laaroussii is higher, with 15–16 teeth in the maxilla compared to the 11–13 of A. madagaskarensis. The teeth of A. laaroussii are also taller than those of A. madagaskarensis and have more closely packed denticles.
|
|
Schramidontus had a subcylindrical smooth carapace and a triangular telson. It had two pairs of grasping maxillipeds, the second being twice as big as the first, that it could use to bring prey to the maxillae, maxillulae and its large mandibles. This feature was not present in its only close relative, Angustidontus, which probably used its maxillipeds to hit and hold its prey. In addition, Schramidontus had six pairs of pereiopods.
|
|
These structures are homologous to the lacinia and galea of maxillae. The labial palps borne on the sides of labium are the counterparts of maxillary palps. Like the maxillary palps, the labial palps aid sensory function in eating. In many species the musculature of the labium is much more complex than that of the other jaws, because in most, the ligula, palps and prementum all can be moved independently.
|
|
Two bright blue eyes peer out of the shell alongside two orange antennae and two orange antennules. The organism also features maxillae to help guide particles of food into its mouth. Some morphological differences arise based upon the geologic habitat the organism resides in. For instance, some individuals of Calcinus elegans found in Hawaii display orange bands on their ambulatory legs, differing from the pure blue bands found in individuals of the Indo-Pacific.
|
|
Rostrum tip Cimex pierces the skin of its host with a stylet fascicle, rostrum, or "beak". The rostrum is composed of the maxillae and mandibles, which have been modified into elongated shapes from a basic, ancestral style. The right and left maxillary stylets are connected at their midline and a section at the centerline forms a large food canal and a smaller salivary canal. The entire maxillary and mandibular bundle penetrates the skin.
|
|
Similarly, the mouthparts of Siphonaptera, some Diptera and Thysanoptera superficially resemble the rostrum of the Hemiptera, but on closer inspection the differences are considerable. Aside from the mouthparts, various other insects can be confused with Hemiptera, but they all have biting mandibles and maxillae instead of the rostrum. Examples include cockroaches and psocids, both of which have longer, many-segmented antennae, and some beetles, but these have fully hardened forewings which do not overlap.
|
|
The lacrimal likely did not form part of the border of either the orbit or nares. The palatine bones of the roof of the mouth in the front part of the snout extensively contacted the maxillae. Some bones in the front part of the palate (likely the vomers) were also covered in small denticles. Denticles were also present in the back of the palate, likely on the pterygoids and rear parts of the palatine bones.
|
|
The majority of Mysida are omnivores, feeding on algae, detritus, and zooplankton. Scavenging and cannibalism are also common, with the adults sometimes preying on their young once they emerge from the marsupium. The pelagic and most other species are filter feeders, creating a feeding current with the exopods of their pereopods. This wafts food particles into a ventral food groove along which they are passed before being filtered by setae (bristles) on the second maxillae.
|
|
Ambedus is a small diadectid known only from maxillae and dentary bones. It is considered the most primitive diadectid because unlike other forms it had a small, shallow lower jaw and many simple, conical teeth. It was also smaller than the later, rather bulky diadectids. Later diadectids have deep jaws with few teeth and forward-projecting incisiforms at the tips of the jaws for consuming plant material, and a corresponding greater girth.
|
|
The skull shows that it had a tall thin bony crest running along the midline of the front of the upper jaw, and a keel on the lower jaw. The teeth at the front of the upper jaw, in the premaxillae, were fanglike, whereas the teeth in the upper cheeks (the maxillae) had three, four, or five cusps, similar to those of Eudimorphodon. Caviramus had a wingspan of about 135 centimeters (53 in).
|
|
Aega psora is the type species of the genus Aega and was first described by Carl Linnaeus in 1758. It reaches in length and is mostly grey, with a faint dorsal stripe. It has slender mandibles and maxillae adapted for sucking blood and some of the setae (bristles) are hooked. The front three pairs of pereiopods (legs) cling on to its host, it inserts its mouthparts and blood is pumped rapidly into the gut.
|
|
The spot-fin beachsalmon is characterized by a deep, laterally compressed, and fusiform body. The dorsal fin is also reduced and begins behind the middle of the body; it contains four spines and 16-18 soft rays. The anal fin originates at about the middle of the body and contains three spines and 26-30 soft rays. The maxillae extend well beyond the small eyes; the preorbital is serrated, and the adipose lid is present.
|
|
The part of the head which projects in front of the first antennae is known as the rostrum or "beak". The mouthparts are small, and consist of an unpaired labrum, a pair of mandibles, a pair of maxillae, and an unpaired labium. They are used to eat "organic detritus of all kinds" and bacteria. The thorax bears five or six pairs of lobed, leaf-like appendages, each with numerous hairs or setae.
|
|
The premaxilae bear strong teeth, with the anterior most tooth being placed directly behind the beginning of the snout. Large nerve foramina are placed close to the dorsal surface of the paired premaxilae. The maxillae bones are unusual for mosasaurids, as they bear teeth which extend posterior to the front of the orbit. It is uncertain exactly how many teeth there were in the maxilla due to breakage, but there is probably around eleven.
|
|
The snout of Colobops is very short, with the portion of the skull in front of the eyes occupying only a quarter of the total length of the skull. This portion of the snout is also reinforced by overlapping bones. For example, the nasal bones (on the upper side of the snout) droop down to internally brace the maxillae (bones of the side of the snout). This feature is also known in rhynchosaurs and rhynchocephalians.
|
|
As an arthropod, D. personata is bilaterally symmetrical. The body is composed of a head, which contains the cephalon, and an elongated trunk, which consists of a thorax and abdomen. From the cephalon, there are two pairs of antennae and a mandible placed anteriorly, in addition to two pairs of maxillae positioned laterally. The trunk sprouts five pairs of walking legs, which are segmented medially to laterally: coxa, basis, ischium, merus, carpus, manus, and dactyl.
|
|
Rautiania fossils were first discovered during a 2005 paleontological expedition into the Orenburg Oblast of Russia. Numerous isolated bones from reptiles of the family Weigeltisauridae were found at the Kul'chumovo-A site. Some of these bones (namely, maxillae and parietals) showed two different morphotypes. In 2006, Russian Academy of Sciences paleontologists Valeriy V. Bulanov and Andrey G. Sennikov described these weigeltisaurid remains as the new genus Rautiania, named after Russian zoologist Aleksandr Sergeevich Rautian.
|
|
Both elements are at the snout tip separated by a gap, ending about thirty-five millimetres in front of the tip of the narrow and flat vomers at the midline. Behind the praemaxillae, the internal wings of the maxillae form the edges of the choanae, the internal nostrils. To the rear of the vomers, triangular palatine bones are located. These are not pierced by large fenestrae though a triangular depression is present at their undersides.
|
|
The snout of Cerrejonisuchus is narrow and consistent in width from the external nares, or nostril openings, to the orbits, or eye sockets. The margin of the snout, unlike that of many long- snouted dyrosaurids, is smooth rather than festooned. "Festooned" refers to the lateral undulations in the maxillae and premaxillae that form around the tooth sockets, or alveoli. The external nares are positioned extremely anteriorly at the very tip of the snout.
|
|
The total length of the individual was estimated as between twenty-four and twenty-eight centimetres. Only the skull shows osteoderms and the authors suggest this was a common developmental stage of all nodosaurids, together with a long middle section of the snout which is characterised by a unique cross-pattern of the bone plates, probably formed by the triangular osteoderms of the maxillae. Propanoplosaurus was by the describers assigned to the Nodosauridae.
|
|
On the maxilla, the alveolar process is a ridge on the inferior surface, and on the mandible it is a ridge on the superior surface. It makes up the thickest part of the maxillae. The alveolar process contains a region of compact bone adjacent to the periodontal ligament (PDL), called the lamina dura when viewed on radiographs. It is this part which is attached to the cementum of the roots by the periodontal ligament.
|
|
The nares (external nostrils) were relatively small and placed high on the skull. Restoration of a nesting individual The jaws of Nemegtomaia were toothless, and like other oviraptorid dinosaurs, it had a short snout with a deep, robust, and somewhat parrot-like beak. It had a hard palate formed by the premaxillae, vomers, and maxillae, like other oviraptorids. The palate was strongly concave (downwards-projecting), and had a cleft on the central part.
|
|
Emanating from the brain several nerves run to the sensory organs (eyes, antennulae, antennae). A pair of circumesophageal ("surrounding the esophagus") connectives connect the brain with the cephalothoracic ganglion. The latter is a compaction of several neuromeres in the lower part of the anterior cephalothorax. These neuromeres correspond morphologically with the body segments of the mandibles and the 1st and 2nd maxillae, the thoracic segments I-VIII and the first pleonal segment.
|
|
Juvenile remains are known from several locations, mostly based on teeth. Thescelosaurus was a heavily built bipedal animal, probably herbivorous, but potentially not. There was a prominent ridge along the length of both maxillae (the tooth-bearing "cheek" bones), and a ridge on both dentaries (tooth- bearing bone of the lower jaw). The ridges and position of the teeth, deeply internal to the outside surface of the skull, are interpreted as evidence for muscular cheeks.
|
|
The development of insect mouthparts from the primitive chewing mouthparts of a grasshopper in the centre (A), to the lapping type (B) of a bee, the siphoning type (C) of a butterfly and the sucking type (D) of a female mosquito. Legend: a, antennae; c, compound eye; lb, labium; lr, labrum; md, mandibles; mx, maxillae hp hypopharynx. Insects have a range of mouthparts, adapted to particular modes of feeding. The earliest insects had chewing mouthparts.
|
|
Situated beneath (caudal to) the mandibles, paired maxillae manipulate and, in chewing insects, partly masticate, food. Each maxilla consists of two parts, the proximal cardo (plural cardines), and distal stipes (plural stipites). At the apex of each stipes are two lobes, the inner lacinia and outer galea (plurals laciniae and galeae). At the outer margin, the typical galea is a cupped or scoop-like structure, located over the outer edge of the labium.
|
|
The defining feature of the order Hemiptera is the possession of mouthparts where the mandibles and maxillae are modified into a proboscis, sheathed within a modified labium, which is capable of piercing tissues and sucking out the liquids. For example, true bugs, such as shield bugs, feed on the fluids of plants. Predatory bugs such as assassin bugs have the same mouthparts, but they are used to pierce the cuticles of captured prey.
|
|
The tooth rows in the maxillae of this specimen are about long. Each alveolus had a foramen (opening) near its side where a replacement tooth could be seen. Compared to other ankylosaurs, the mandible of Ankylosaurus was low in proportion to its length, and, when seen from the side, the tooth row was almost straight instead of arched. The mandibles are completely preserved only in the smallest specimen (AMNH 5214) and are about long.
|
|
The maxillae have 11 and 13 on the right and left sides respectively, there is room for at least 17 teeth for each element. Smaller teeth are present along the sloping surface of the transverse flange, anterior to the large row of teeth. On the parasphenoid plate, two separate paired rows of teeth diverge posteriorly. The lateral-most rows sit on a ridge that runs the length of the main body of the parasphenoid.
|
|
These are evident in what are known as nutrient foramina. These nutrient foramina, present on the maxillae of the whale, are associated with grooves and sulci, or fissures, which in life are occupied by branches of the superior alveolar artery and nerve. This superior alveolar artery supplies nutrients to the epithelial, or surface cells of the body, from which the baleen continuously develops. In all known archaeocetes and odontocetes, nutrient foramina are absent.
|
|
Agrostichthys parkeri has an elongated, vertically compressed body which slims down to a point at the end. The body is not covered in scales, but rather small, horny nodules (dermal tubercles) that extend in longitudinal rows down the length of the body. Agrostichthys parkeri has a defined, protruding mouth with outer enlarged maxillae on a small, slender head that continues seamlessly right into the elongated body. Only the upper jaw protrudes, forming a long, tubular opening.
|
|
The pair of terga at the free end are trapezoid and more furrowed than the scutum and the carina in between are wide and forked. The tergal flaps are yellow, giving a coloured rim to the plates in the living animal. The body concealed by these plates consists of a head and thorax with a vestigial abdomen. The head bears the mouthparts consisting of a labrum with fine teeth on the inner margin, a blunt palpus, mandibles and maxillae.
|
|
Gamerabaena is an extinct genus of baenid turtle which existed in North Dakota during the late Cretaceous Period. It is known from a single fragmentary skull that was found in the Maastrichtian-age Hell Creek Formation. It contains the species Gamerabaena sonsalla. Gamerabaena is similar to the genus Palatobaena, but it differs in its lack of a posterior expansion of the triturating (or chewing) surface, a somewhat rectangular skull, and a wide angle between the maxillae.
|
|
The upper surface of a typical iguanodontid skull has a convex curve that extends from the snout to just past the orbit, where the skull flattens out to form a roughly level plane directly above the braincase. The antorbital fenestra, an opening in the skull anterior to the eye sockets, is reduced in size in iguanodontids. Their maxillae are roughly triangular, fairly flat, and sport thickened bony walls. An elongated maxilla is characteristic of the family.
|
|
B. bimaculatus queens forage on Aquilegia flowers. The queens hang upside down on stamens, clutch the filament with their forelegs, and scrape off pollen using their middle and hind legs. Workers enter the Aquilegia spurs by pushing their head and part of their thorax into the spur's mouth. They then extend the maxillae and tongue into the spur to drink nectar, repeating this process on multiple spurs of the same plant before visiting the next one.
|
|
The marsupial lion was a highly specialised carnivore, as is reflected in its dentition. Like other diprotodonts, it possessed enlarged incisors on both the upper (maxillae) and lower (mandibles) jaws. These teeth (the lower in particular) were shaped much more like the pointed canine teeth of animals such as dogs and cats than those of kangaroos. The most unusual feature of the creature's dentition were the huge, blade-like carnassial premolars on either side of its jaws.
|
|
Aega antarctica can grow to a length of up to but most individuals are less than long. This isopod is an elongate oval when viewed from above and has two large compound eyes and two pairs of antennae. The first pair of antennae are short with thirteen whip-like segments (known as articles) and the second pair longer with fifteen articles. The long slender maxillae and mandible are specialised for puncturing the skin of the host fish.
|
|
Inside the lacrimal bones were depressions that may have held glands, such as salt glands. Within the maxillae were sinuses that were better developed than those of more basal theropods such as Ceratosaurus and Marshosaurus; they may have been related to the sense of smell, perhaps holding something like Jacobson's organs. The roof of the braincase was thin, perhaps to improve thermoregulation for the brain. The skull and lower jaws had joints that permitted motion within these units.
|
|
Restoration The lacrimal has a thick rugose ridge extending back from that on the nasal. Its lamellar part forms the posterodorsal border of the antorbital fenestra, and is articulated with the maxillae which form much of the rest of the borders. There is also a descending process of the lacrimal which forms most of the posterior border of the antorbital fenestra, with a noticeably striated ridge. This descending process would probably have contacted the jugal at its ventral end.
|
|
The genus was erected in 1872 by Ludwig Koch. He placed four species in the genus, including the species then known as Epeira malabarensis, first described by Walckenaer in 1842. Koch described Nephilengys as very similar in the form of the cephalothorax, maxillae and labium to Nephila, but differing in the position of the eyes, and in leg lengths. The name Nephilengys refers to the close relationship with Nephila: Nephilengys = Nephila + Ancient Greek -engy-, "near to" or "close to".
|
|
Upon removal, special care was taken to protect any bones that may be lost or damaged. For example, all maxillae bones and mandibles were wrapped to prevent the teeth from falling out and crania were removed with soil still attached (a measure that helps to prevent the bones from fragmenting). These and other large elements like long bones, scapulae, sacra, and innominate bones were bagged individually and assigned their own unique catalogue number. All small elements (e.g.
|
|
A typical fish louse of the genus Argulus is very flat with an oval or rounded carapace, two compound eyes, sucking mouthparts with a piercing stylet, and two suction cups it uses to attach to its host. These "suctorial organs" are the first of its two pairs of maxillae, modified in shape. Its paired appendages have hooks and spines, and are used for swimming. A. foliaceus in particular is up to 7 millimeters long by 5 millimeters wide.
|
|
Cryonectes is a moderate-sized pliosaurid, as its skull has a length of . The specimen when discovered was prepared first with acid, which damaged some parts, especially the teeth, which are now broken and lack enamel. The complete mandible and the skull are in occlusion with teeth in situ and one separated and almost complete tooth is also known. The premaxillae and maxillae are partially preserved and the most important part of the palate is preserved separate from the skull.
|
|
Restoration of A. scagliai Aetosauroides was proposed to be synonymous with the genus Stagonolepis in 1996 and 2002. Smaller specimens of both species were placed with Stagonolepis robertsoni, and larger specimens were considered to be S. wellesi. This synonymy is not accepted, with several studies identifying unique features that distinguish Aetosauroides from Stagonolepis. Among these are maxillae that do not touch the nostrils, oval- shaped holes on the centra of the vertebrae, and a convex margin of the lower jaw.
|
|
Diagram of a single maxilla from the cockroach Periplaneta americana showing the anatomy and musculature The generalized condition in hexapods is for the first pair of maxillae to consist of a basal triangular sclerite called the cardo and a large central sclerite called the stipes from which arise three processes: the lacinia, the galea and the maxillary palp. The lacinia is often strongly sclerotized and toothed. It functions to cut and manipulate food in the mouth.Gullan, P. J. and Cranston, P. S. 2005.
|
|
A cast of C. ohioensis assembled from various specimens The Castoroides fossils were discovered in 1837 in a peat bog in Ohio, hence its species epithet ohioensis. Catalogue no.1195, Mus. North. Ind. Hist. Soc. Well- preserved skull of Castoroides ohioensis but with the mandibles lost, both zygomatic arches missing, and the facial portions of the maxillae broken away; dental series complete and in good condition. Castoroides had cutting teeth up to 15 cm-long with prominently-ridged outer surfaces.
|
|
Members of this genus live in thick, parchment-like tubes that project from the sediment on the seabed. The tubes are covered on the outside by fragments of shell, algae, fibers and other small objects, collected by the worm and stuck in place by mucus. The worm's tube is a food-catching tool that creates a small micro-reef where small invertebrate prey reside. Diopatra dart partially out of the tube and grasp the prey with their maxillae and mandibles.
|
|
Irritators teeth were circular in cross section, as opposed to the laterally flattened condition of most theropod teeth. The enamel (first layer of the teeth) was thin, with a finely wrinkled texture also observed in Baryonyx. Both of Irritators maxillae preserve nine teeth, although the left maxilla's tooth crowns are more intact, and there are traces of a tenth tooth in the rock matrix. The teeth were deeply inserted into the jaw and widely spaced towards the front of the maxilla.
|
|
The front of the snout was expanded, forming the spoon-shaped terminal rosette characteristic of spinosaurids. This concave underside of the premaxillae would have complemented a convex and enlarged mandible tip. The premaxillae connected with each other on the bottom to form Angaturamas secondary palate, which was also partially contributed to by two processes extending from the maxillae. The snout was strongly compressed laterally, and the premaxillae gently tapered towards the top to form a tall sagittal crest in thickness.
|
|
The upper jaw of T. sethi was primarily composed of premaxillae and maxillae; the suture which formed the border between these bones is not visible. As in all members of its clade, the jaws were edentulous (toothless). The rostrum (snout) was long from the tip of the premaxilla to the joint where the quadrate bone of the skull connected with the articular bone of the lower jaw. The front of the premaxillae had sharp upper and lower edges, unique to this species.
|
|
When the mouth is closed, the fangs fit into grooved slots in the buccal floor and usually below the front edge of the eye and are angled backwards; some elapids (Acanthophis, taipan, mamba, and king cobra) have long fangs on quite mobile maxillae and can make fast strikes. A few species are capable of spraying their venom from forward-facing holes in their fangs for defense, as exemplified by spitting cobras. Venom may cause intense pain, if not blindness, upon contact with eyes.
|
|
Mythunga is known from a partial skull, holotype QM F18896 found in April 1991 by Philip Gilmore in marine rocks of the late Albian-age Toolebuc Formation at Dunluce Station west of Hughenden, Queensland. Only the middle snout and corresponding parts of the lower jaws are known, including the rear of a left premaxilla, the lower parts of both maxillae, the rear dentaries and a right splenial. They were three-dimensionally preserved, associated in a chalk nodule. It represents a subadult individual.
|
|
Teeth of Kwanasaurus have been found both as isolated material and within maxillae and dentaries. Isolated teeth are leaf-shaped, with coarse denticles, slightly flattened sides, and crown tips more than halfway towards the rear of the tooth. The lingual (tongue) side of the tooth has a thick vertical ridge covered in striations. Sacisaurus, Eucoelophysis, and possibly Technosaurus are the only other silesaurids known to possess similar teeth, although leaf-shaped teeth are also common in various other herbivorous archosaurs.
|
|
This region bears a pair of maxillipeds, and the head also has two pairs of maxillae, a pair of limb-like mandibles, and two pairs of long antennae. The appendages on the head are much longer than those on the thorax, and have a number of fine hairs that the animal uses to strain detritus from the water to feed on. They have a single naupliar eye. After mating, mystacocarids lay tiny eggs which hatch into a nauplius or metanauplius larva.
|
|
The upper jaw contains a secondary palate which separates the nasal passages from the rest of the mouth, which would have given Thrinaxodon the ability to breathe uninterrupted, even if food had been kept in its mouth. This adaptation would have allowed the Thrinaxodon to mash its food to a greater extent, decreasing the amount of time necessary for digestion. The maxillae and palatines meet medially in the upper jaw developing a midline suture. The maxillopalatine suture also includes a posterior palatine foramen.
|
|
The rough- haired golden mole sometimes feeds above ground, and, when it does, it roots about like a pig in search of worms and insects. It walks at night to foraging sites that are recognizable by the disturbed soil where these golden moles have rooted for insects with their horny nose pads.[6] They have a pair of bones, called tabulars, in the occipital area of the skull, which are not found in other mammals. The zygomatic arches are formed by elongations of the maxillae.
|
|
However, in the back, the cutting edge of the beak is dull compared to sea turtles. Much of the length of the head derives from the elongated premaxillae–which is the front part of the beak in this animal–and maxillae. The jugal bones, the cheek bones, due to the elongate head, do not project as far as they do in other turtles. The nostrils are elongated and rest on the top of the skull, slightly posited forward, and are unusually horizontal compared to sea turtles.
|
|
Iguanodontidae is a family of iguanodontians belonging to Styracosterna, a derived clade within Ankylopollexia. Characterized by their elongated maxillae, they were herbivorous and typically large in size. This family exhibited locomotive dynamism; there exists evidence for both bipedalism and quadrupedalism within iguanodontid species, supporting the idea that individual organisms were capable of both locomoting exclusively with their hind limbs and locomoting quadrupedally. Iguanodontids possess hoof-like second, third, and fourth digits, and in some cases, a specialized thumb spike and an opposable fifth digit.
|
|
Carnivory can be inferred for Teleocrater from the single tooth that was preserved, which is compressed, recurved, and bears serrations on both edges. Like other members of the Archosauria, the recess in the maxilla in front of the antorbital fenestra (the antorbital fossa) extends onto the backward- projecting process of the bone, and the palatal projection of the two maxillae contacted each other. Additionally, like early dinosaurs, there is a depression on the frontal bone in front of the supratemporal fenestra (the supratemporal fossa).
|
|
Labrum is the "upper lip" which is in the front area of the head and is the most exterior part. A pair of mandible is found on backside of the labrum flanking the side of the mouth, succeeded by a pair of maxillae each of which is known as maxilliary palp. At the back side of the mouth is the labium or lower lip. There is also an extra mouth part in some insects which is termed as hypopharynx which is usually located between the maxillac.
|
|
Figure 2: Ventral view of forcipules of a centipede, arising from the first body segment Myriapods comprise four classes of arthropod, each with a similar morphology: Class Chilopoda (centipedes); class Diplopoda (millipedes); class Pauropoda; and class Symphyla. Myriapod mouthparts are similar to those of chewing insects, although there is some variation between the myriapod classes. A labrum is present but sometimes is not obvious and forms an upper lip, often in association with an epistome. The labium is formed by first maxillae in diplopoda forming the gnathochilarium.
|
|
Many different species of insects have mouthparts derived from the same embryonic structures, indicating that the mouthparts are modifications of a common ancestor's original features. These include a labrum (upper lip), a pair of mandibles, a hypopharynx (floor of mouth), a pair of maxillae, and a labium. (Fig. 2c) Evolution has caused enlargement and modification of these structures in some species, while it has caused the reduction and loss of them in other species. The modifications enable the insects to exploit a variety of food materials.
|
|
The mouthparts are adapted for chewing with powerful mandibles and a pair of maxillae, each with a segmented palp. Adjoining these is the labium-hypopharynx which houses a tubular spinneret which is able to extrude silk. Caterpillars such as those in the genus Calpodes (family Hesperiidae) have a specialized tracheal system on the 8th segment that function as a primitive lung. Butterfly caterpillars have three pairs of true legs on the thoracic segments and up to six pairs of prolegs arising from the abdominal segments.
|
|
The type species is S. venezuelensis. Like other gavialoids, Siquisiquesuchus had a long, narrow rostrum on its skull, accounting for approximately 60% of the skull's length. The number of teeth in the premaxillary bones at the tip of the snout is not known, but the maxillae making up most of the rostrum had at least 20 teeth each, and the dentaries of the lower jaws had at least 23. Some details of the described skulls cannot be determined because the sutures are not visible.
|
|
A beetle leg In invertebrate biology, an appendage (or outgrowth) is an external body part, or natural prolongation, that protrudes from an organism's body (in vertebrate biology, an example would be a vertebrate's limbs). An appendage is any of the homologous body parts that may extend from a body segment. These include antennae, mouthparts (including mandibles, maxillae and maxillipeds), gills, walking legs (pereiopods), swimming legs (pleopods), sexual organs (gonopods), and parts of the tail (uropods). Typically, each body segment carries one pair of appendages.
|
|
The maxillae occupy a lateral position, one on each side of the head behind the mandibles. The proximal part of the maxilla consists of a basal cardo, which has a single articulation with the head, and a flat plate, the stipes, hinged to the cardo. Both cardo and stipes are loosely joined to the head by membrane so they are capable of movement. Distally on the stipes are two lobes, an inner lacinea and an outer galea, one or both of which may be absent.
|
|
The head of Scutigera coleoptrata, showing antennae, compound eyes and mouthparts Myriapods have a single pair of antennae and, in most cases, simple eyes. Exceptions include the large and well-developed compound eyes of Scutigera The mouthparts lie on the underside of the head, with an "epistome" and labrum forming the upper lip, and a pair of maxillae forming the lower lip. A pair of mandibles lie inside the mouth. Myriapods breathe through spiracles that connect to a tracheal system similar to that of insects.
|
|
247 was low, without elevated rims over the eyes, and was long. The snout was short and pointed compared to Cretaceous alligatorids. Its premaxillae (the bones of the tip of the snout) had five teeth each, while the maxillae (main tooth-bearing bones of the upper jaw) had thirteen teeth each, with the fourth being the largest and the last three having broad flattened crowns. The lower jaws had twenty teeth on each side, and like the upper jaws, the last five had broad crushing crowns.
|
|
Schramidontus was found in a continental environment, and although this represents the first documentation of continental angustidontids, it differs from the marine environment in which Angustidontus is usually found. The first two pairs thoracopods are inserted laterally in the mouth. Several factors such as the size and articulation of the three endopodal articles suggest that these thoracopods were able to bring prey to the maxillae, maxillulae and its large mandibles. In addition, the spiny occlusal margins of their dactyli suggest that the genus was fed by filtration.
|
|
All other silesaurid maxillae recovered from the area seem to represent the same taxon, indicating that Kwanasaurus was likely the only silesaurid from the Eagle Basin. With this in mind, all other Eagle Basin fossils resembling those of silesaurids have been referred to the taxon. These include multiple dentaries, teeth, ilia, femora, and a humerus. Dinosauromorph-like tibia and scapulae from the area may also belong to Kwanasaurus, though they have not been referred to the genus due to lacking any clear silesaurid features.
|
|
Maxillae, including the holotype, DMNH EPV.65879, A-H The maxilla is much deeper and more robust in Kwanasaurus than in any other silesaurid. There are replacement pits on the inner edge of the tooth row similar to those of thyreophorans, and smaller and more numerous pits on the outer surface of the maxilla. Five of the replacement pits at the midlength of the bone are set in a groove, a trait also present in Silesaurus and silesaurid skull material from the Ntawere Formation.
|
|
Maxillae of Eolambia The crestless skull of Eolambia has a similar overall shape to those of Equijubus and Probactrosaurus. The front of the snout is highly roughened, being punctuated by many foramina (openings). At the tip of each premaxilla, there are two tooth-like structures known as denticles, which is also seen in its closest relative Protohadros. Further back, the rear portion of the lower branch of the premaxilla abruptly projects upwards, closing off the nostril at the rear as in Probactrosaurus, Protohadros, and other hadrosauroids.
|
|
Unlike other proterochampsians, the nares (nostril holes) did not seem to be oriented upwards. The rear branch of the premaxilla wedges into an extensive suture between the nasal and maxilla. There were 20 teeth in the maxillary tooth row, significantly more than in the maxillae of proterochampsids but in line with other doswelliids. Four enlarged teeth in the front half of the tooth row are covered by a convex extension, giving the maxilla a sigmoid lower edge akin to that of "robust-morph" phytosaurs.
|
|
Galadi is an extinct genus of predatory bandicoot from Oligo-Miocene deposits of Riversleigh, northwestern Queensland, Australia. It was first named by K.J. Travouillon, Y. Gurovich, R.M.D. Beck and J. Muirhead in 2010 and the type species is Galadi speciosus; additional three species, G. adversus, G. amplus and G. grandis, were described in 2013. The genus is represented by three well-preserved skulls and several isolated maxillae and dentaries. Its body mass would have been close to two pounds, making it relatively large for its family.
|
|
The maxillae still "grip" the "food" while the mandibles "bite" it. The top of the mouth, the labrum, has developed into a channeled blade the length of the proboscis, with a cross-section like an inverted "U". Finally, the hypopharynx has extended into a tube that can deliver saliva at the end of the proboscis. Its upper surface is somewhat flattened so, when the lower part of the hypopharynx is pressed against it, the labrum forms a closed tube for conveying blood from the victim.
|
|
A proteroglyphous snake. A king cobra skull (Ophiophagus hannah)Proteroglyphous snakes (forward grooved) have shortened maxillae bearing few teeth except for a substantially enlarged fang pointing downwards and completely folded around the venom channel, forming a hollow needle. Because the fangs are only a fraction of an inch long in even the largest species these snakes must hang on, at least momentarily, as they inject their venom.LD50 for various snakes Some spitting cobras have modified fang tips allowing them to spray venom at an attacker's eyes.
|
|
Pedipalps are composed of six segments or articles: the coxa, the trochanter, the femur, the short patella, the tibia, and the tarsus. In spiders, the coxae frequently have extensions called maxillae or gnathobases, which function as mouth parts with or without some contribution from the coxae of the anterior legs. The limbs themselves may be simple tactile organs outwardly resembling the legs, as in spiders, or chelate weapons (pincers) of great size, as in scorpions. The pedipalps of Solifugae are covered in setae, but have not been studied in detail.
|
|
Pachycheilosuchus (meaning "thick lipped crocodile") is an extinct genus of mesoeucrocodylian from the Early Cretaceous of Texas, United States. Previously known, in part, as the "Glen Rose form", this crocodylomorph is notable for its procoelous vertebrae, otherwise found only in derived eusuchian crocodilians (the vertebrae articulate with a cup on the anterior surface and a rounded posterior surface), a thick margin on the maxillae (the main tooth-bearing bones of the upper jaw; thus "thick lipped crocodile"), and a shield of armor on the neck formed by the fusion of six individual scutes.
|
|
Additionally, a 49 millimeter-long (1.9 in) crocodyloid egg was recovered with the skeletal fossils, and is of reasonable size to have come from an individual with a length of 63.5 centimeters, suggesting that some of the individuals were sexually mature. The maxillae had overhanging lips along their outer margins, and the tooth row was set away from the margin. One maxilla has an oval puncture mark, 5 millimeters by 6.5 millimeters (0.2 by 0.26 in), probably made by a larger predator. The snout was short and flat.
|
|
The antennae are well-developed but variable, being thread-like, feathery or comb-like in the different families. The mouthparts are adapted for piercing and sucking, as in the black flies, mosquitoes and robber flies, and for lapping and sucking as in many other groups. Female horse-flies use knife-like mandibles and maxillae to make a cross-shaped incision in the host's skin and then lap up the blood that flows. The gut includes large diverticulae, allowing the insect to store small quantities of liquid after a meal.
|
|
Rostrals and tectals are small skull bones scattered around the snout, which are present in tetrapodomorph fish but lost in true tetrapods. Both maxillae (toothed bones at the side of the snout) are well-preserved, but not particularly specialized. The premaxillae and maxilla bear numerous tapering teeth, with about 11 on each premaxilla and up to 24 on each maxilla. This is slightly more than Ichthyostega (which has 8-10 on the premaxilla and 16-23 on the maxilla), and Ymeria further differs by having the largest teeth be slightly further forwards in the snout.
|
|
The German State Museum of Natural History Karlsruhe obtained a pterosaur fossil from an illegal commercial digger who had found it somewhere near Santana do Cariri in the Araripe Basin. The deposits it was recovered from likely belong to the Santana Formation of northeastern Brazil, which was dated by Martill to the latest Albian stage of the Cretaceous period. The specimen is catalogued as SMNK PAL 6597, and represents a partial skull consisting only the fused premaxillae and maxillae, some teeth and parts of the palate. The frontmost centimeter of the snout tip is missing.
|
|
The lower back teeth were close together, and the space between the teeth increased from front to back, suggesting they were used for shearing, unlike the suction-feeding modern-day sperm whales which lack teeth in their upper jaws. The front teeth were more worn on the sides, whereas the bottom teeth were more worn along the middle. It had 12 teeth in the upper jaw and 13 teeth in the bottom jaw, and like other raptorials, it had tooth enamel. The premaxillae bore three teeth, and the maxillae had nine teeth.
|
|
Rajasaurus was then formally described in 2003 by geologist Jeffrey A. Wilson and colleagues. The holotype specimen of Rajasaurus comprises a partial skeleton, GSI Type No. 21141/1-33, which includes the maxillae, premaxillae, braincase, and quadrate bone on the skull; and spine, hip bone, legs, and tail in post-cranial remains. It is the first Indian theropod to have preserved these post-cranial remains. It is possible Rajasaurus, Lametasaurus, and Indosaurus are synonymous, though this cannot be confirmed due to fragmentary remains, and the Lametasaurus specimen has been lost.
|
|
Psephoderma had a long, narrow rostrum, which was the main difference between its skull and those of its relatives. This rostrum bore paired grooves on the inside of the mouth, which led to the internal nares and are a diagnostic feature for the genus. The anterior processes of the maxillae stretched forwards a long way along the rostrum, while the posterior processes of the premaxillae stretched a long way back up the rostrum and came between the external nares and between the nasal bones. The nasal bones were very small, mere splinters of bone.
|
|
Teeth were present only in the maxillae (upper cheeks) and dentaries (main bone of the lower jaw). They grew in columns, with an observed maximum of six in each, and the number of columns varied based on the animal's size. There were 51 to 53 columns per maxilla and 48 to 49 per dentary (teeth of the upper jaw being slightly narrower than those in the lower jaw). Life restoration E. regalis had thirteen neck vertebrae, eighteen back vertebrae, nine hip vertebrae, and an unknown number of tail vertebrae.
|
|
Holotype of Angaturama limai from various angles The holotype of Angaturama limai consists only of the front part of the upper jaw, comprising the tips of the paired premaxillae and the frontmost ends of the maxillae. The specimen measures in height and in length, with the width of the palatal region being . The suture between the maxilla and premaxilla was jagged at the front and straightened out towards the rear. The lower margin of the premaxillae was concave, with the concavity reaching its apex at the sixth premaxillary tooth.
|
|
The known teeth of the front part of the lower jaw were large fangs, and the teeth at the back of the jaws appear to have been smaller. The dentition of elasmosaurids was generally heterodont (irregular throughout the jaws), with the teeth becoming progressively smaller from front to back. The maxillae (largest tooth bearing bone of the upper jaw) of elasmosaurids usually contained 14teeth, whereas the dentaries (the main part of the lower jaws) usually contained 17 to 19. The teeth interlocked, and their tooth crowns were slender and rounded in cross-section.
|
|
The alveolar margin is vertically oriented, but runs anteroposteriorly rather than transversely as that of the premaxilla does. The maxilla is quite highly textured with pits and neurovascular canals, although far less than the nasal, frontal and parietal bones in particular. The maxillae also form much of the palate, particularly at the anterior section of the palate; the palatine bones form almost all the remainder. The median one- third (measured transversely from left to right) is arched dorsally, making the buccal cavity larger, whereas the two lateral thirds by this measure are horizontal.
|
|
Oral and maxillofacial pathology refers to the diseases of the mouth ("oral cavity" or "stoma"), jaws ("maxillae" or "gnath") and related structures such as salivary glands, temporomandibular joints, facial muscles and perioral skin (the skin around the mouth). The mouth is an important organ with many different functions. It is also prone to a variety of medical and dental disorders.Mouth Disease Information Retrieved on 2010-02-01 The specialty oral and maxillofacial pathology is concerned with diagnosis and study of the causes and effects of diseases affecting the oral and maxillofacial region.
|
|
It also bears a pair of stalked compound eyes, as well as a sessile median eye, two pairs of antennae, and the mouthparts. The mouthparts comprise a labrum, directed backwards over the mouth and pairs of mandibles, paragnatha, maxillules and vestigial maxillae. The thorax is made up of twelve body segments, the last of which is fused to the first segment of the abdomen. There is no carapace, but each of the eleven free segments bears a pair of phyllopodia, which have a series of bristles pointing along the animal's midline.
|
|
Chewing insects have two mandibles, one on each side of the head. The mandibles are positioned between the labrum and maxillae. The mandibles cut and crush food, and may be used for defense; generally, they have an apical cutting edge, and the more basal molar area grinds the food. They can be extremely hard (around 3 on Mohs, or an indentation hardness of about 30 kg/mm2); thus, many termites and beetles have no physical difficulty in boring through foils made from such common metals as copper, lead, tin, and zinc.
|
|
The front of the snout expanded into a spatulate (spoon-like), "terminal rosette", a shape similar to the rostrum of the modern gharial. The front of the lower margin of the premaxillae was downturned (or hooked), whereas that of the front portion of the maxillae was upturned. This morphology resulted in a sigmoid or S shaped margin of the lower upper tooth row, in which the teeth from the front of the maxilla were projecting forward. The snout was particularly narrow directly behind the rosette; this area received the large teeth of the mandible.
|
|
The proboscis, as seen in adult Lepidoptera, is one of the defining characteristics of the morphology of the order; it is a long tube formed by the paired galeae of the maxillae. Unlike sucking organs in other orders of insects, the Lepidopteran proboscis can coil up so completely that it can fit under the head when not in use. During feeding, however, it extends to reach the nectar of flowers or other fluids. In certain specialist pollinators, the proboscis may be several times the body length of the moth.
|
|
Restoration Fukuivenator had an estimated length of 245 centimetres and an estimated weight of twenty-five kilogrammes. Distinctive traits include spatulate teeth in the front praemaxillae, pointed, recurved and unserrated teeth in the maxillae and a long neck with elongated neck vertebrae. The anatomy of Fukuivenator shows a unique combination of primitive and advanced coelurosaurian features. A phylogenetic analysis performed by the research team that described Fukuivenator found it to be a primitive member of the group Maniraptoriformes, in an unresolved position equally closely related to ornithomimosaurs, maniraptorans, and Ornitholestes.
|
|
Arripis truttacea has a streamlined, moderately deep, slightly elongate body which is a little compressed with a relatively narrow caudal peduncle and a moderately small head. The eyes are quite small with an obvious growth of transparent adipose tissue on the anterior and posterior edges of the eye on larger fish. There is a series of fine serrations along the lower edge of the preorbital bone but these largely disappear in larger fish. The mouth is moderate in size and is oblique, its maxillae reaches a level below the centre of eyes.
|
|
The abdomen consists of ten segments, some of which may be obscured by a large pair of operculate gills, a thoracic shield (expanded part of the prothorax) or the developing wing pads. In most taxa up to seven pairs of gills arise from the top or sides of the abdomen, but in some species they are under the abdomen, and in a very few species the gills are instead located on the coxae of the legs, or the bases of the maxillae. The abdomen terminates in a pair of, or three, slender thread-like projections.
|
|
Lying above the oesophagus is the brain or supraesophageal ganglion, divided into three pairs of ganglia: the protocerebrum, deutocerebrum and tritocerebrum from front to back (collectively no. 5 in the diagram). Nerves from the protocerebrum lead to the large compound eyes; from the deutocerebrum to the antennae; and from the tritocerebrum to the labrum and stomatogastric nervous system. Circum- oesophageal connectives lead from the tritocerebrum around the gut to connect the brain to the ventral ganglionated nerve cord: nerves from the first three pairs of ganglia lead to the mandibles, maxillae and labium, respectively.
|
|
The animal's mouthparts comprise paired mandibles, maxillules, maxillae and three pairs of maxillipeds, although the third maxillipeds are very long and more closely resemble the walking legs than the other mouthparts. There are five pairs of walking legs, or pereiopods, diminishing in size from front to back. There are no chelae (claws), although the last segment may be able to grip against an extension of the previous segment in some cases (subchelate). The first four pairs are similarly arranged, extending forwards and downwards to be used in walking; the fifth pair is directed upwards.
|
|
Unlike most other early tetrapods which have rounded or pointed snouts, Spathicephalus mirus has a flattened, almost perfectly square- shaped skull up to in both width and length. The squared shape is caused primarily by a widening of the paired nasal bones along the midline of the snout. The premaxilla bones at the tip of the snout form the entire front edge of the square, while the maxilla bones form the side edges. The maxillae of Spathicephalus are unusual in being thin (no more than in thickness) along their entire length.
|
|
Morphology of stomatopods is consistent with most malacostracans in that they have three main body segments: the cephalon, the thorax and the abdomen. The abdomen is made up of six segments, five of which possess a pair of pleopods, which are used for respiration and swimming. The key appendage used by stomatopods for fighting behaviour is referred to as the raptorial appendage, which is actually a pair of enlarged second maxillipeds just behind the maxillae. These strong maxillipeds are used for purposes of prey capture in addition to fighting.
|
|
Compared to other adapiform primates, the fossil record of Sivaladapis is limited, lacking any cranial or postcranial fossil material. The genus is known exclusively from isolated fossil teeth and partial dentaries and maxillae recovered from the Chinji Formation (Siwalik Group) of India and Pakistan. Both S. nagrii and S. palaeindicus are considered a fairly large adapiforms, with body-size estimates ranging from 2.6 to 3.4 kilograms. The prominent and well-developed shearing crests on its molars and premolars suggests the genus was adapted to a predominately folivorous diet, subsisting on fibrous leaves.
|
|
A dragonfly has two mandibles, which are used for chewing, and two maxillae, which are used to hold the food in place as it is chewed. The labium forms the floor of the dragonfly's mouth, the labrum forms the top, while the hypopharynx is inside the mouth and is used in swallowing. Conceptually, then, the mosquito's proboscis is an adaptation of the mouthparts that occur in other insects. The labium still lies beneath the other mouthparts, but also enfolds them, and it has been extended into a proboscis.
|
|
The Aglycyderini have several highly distinctive characters as adults: The rostrum of adult Aglycyderini is very short compared to the average belid and attaches exactly symmetrically at the tip of the head; at first glance, do not look "snouted" but merely somewhat long-headed. Viewed in profile, the head is flat-sided and almost triangular in males, and somewhat swollen and rounded in females. The prementum is large and prevents the maxillae from being seen from below. The sternite of the mesothorax is slightly convex and extends to between the midlegs in a smooth inward curve.
|
|
The remains of Ekrixinatosaurus helped fill in more information about abelisaur anatomy as it contained portions of the skeleton that were previously unknown, unpublished, or poorly preserved in other specimens. The holotype skeleton (MUCPv-294) was well preserved yet disarticulated. It contained elements including a left and partial right maxillae; basicranium; both dentaries; teeth; cervical, a dorsal, sacral and caudal vertebrae; haemal arches; ribs; ilia, pubis and proximal ischia; left and distal end of right femur; left tibia; left astragalus and calcaneum; proximal end of left fibula and right tibia; metatarsals; phalanges; and a pedal ungual.
|
|
It meets the nasal bone where it presents a rough, uneven serrated notch known as the nasal notch, and this articulates on either side of the middle line with the nasal bone, and laterally with the frontal process of the maxilla and with the lacrimal. This part is sometimes called the nasal part of frontal bone. The term nasion is applied to the middle of the frontonasal suture. From the center of the notch the nasal process projects downward and forward beneath the nasal bones and frontal processes of the maxillae, and supports the bridge of the nose.
|
|
Although the dentary bones assigned are nearly complete anteriorly, their morphology cannot confirm the entire depth or height of the lower jaw at the symphysis. This is because the dentary contributes only to the dorsal half of the symphysis in caseids, and the splenial most likely contributed to the symphysis, as it formed the lower part of the symphyseal region of the mandible. The assignment of these dentaries to Arisierpeton is based mainly on dental features, and to some extent on the labial surface characteristics of the bone. The teeth of these dentaries are identical to those found on the maxillae.
|
|
The head bears two pairs of antennae, the first of which is often biramous (branching into two parts) and the second pair bear exopods (outer branches) which are often flattened into antennal scales known as scaphocerites. The mouthparts consist of pairs each of mandibles, maxillules (second pair of mouthparts) and maxillae. Usually a pair of stalked compound eyes is present, although in some taxa the eyes are unstalked, reduced or lost. Up to three thoracic segments may be fused with the head to form a cephalothorax; the associated appendages turn forward and are modified as maxillipeds (accessory mouthparts).
|
|
The fifth and sixth pleonal somites expanded laterally, with some partial overlap over the telson. Angustidontus had large grasping appendages, modified from the first or second thoracopods, which represent some of the earliest maxillipeds within the Eucarida. These maxillipeds were likely used through being folded downwards to strike at prey, then hold the prey and prevent it from wriggling itself free. Schramidontus, the only known close relative of Angustidontus, also possessed a second smaller pair of maxillipeds that it could use to bring prey to the maxillae, maxillulae and its large mandibles, but these are absent in Angustidontus.
|
|
The maxillae are also protected by the large prefrontals (bones in front of the eyes), similar to the condition in turtles. The prefrontals are also contacted by the wide palatine bones of the roof of the mouth, similar to lepidosaurs (squamates and rhynchocephalians), as well as turtles. All of these features exist to strengthen the front part of the skull, which explains how they convergently evolved in multiple different types of reptiles. The original fossil prior to further preparation and 3D rendering Colobops also possesses large orbits (eye holes), although this may be a juvenile feature.
|
|
All of the teeth were either completely flattened or weakly pointed, and many of the teeth bore a constriction between the root and the crown. Unlike other ichthyosauriforms with molariform teeth, all of the tooth crowns were "swollen" to a similar extent. On the maxilla (upper jawbone) and dentary (lower jawbone), the teeth were arranged in three rows, with the outermost row having the most and largest teeth; the maxillae had seven, five, and probably one teeth each, while the dentaries had ten, seven, and four teeth each. Among ichthyosauriforms, only Cartorhynchus and Xinminosaurus have multiple rows of teeth.
|
|
Extending from it was an elongate and low snout, with both sides relatively flat and slightly angled towards the skull midline. Only the rear ends of the paired (frontmost snout bones) remain intact, forming the front upper and lower borders of the (bony nostrils). As in all spinosaurids, the (main upper jaw bones) extended below and past the nostrils in a long, low branch that formed the lower border of this opening, consequently separating the premaxillae and bones in that location. Irritators maxillary sinuses (located in the body of the maxillae) bore a large oval opening, as in Allosaurus.
|
|
Life restoration with size compared to a human The holotype of Sinotyrannus is KZV-001, a disarticulated partial skeleton including the front portion of the skull, three dorsal vertebrae, the incomplete ilia, three articulated manual phalanges (including an ungual), and other fragmentary bones. In 2010 Gregory S. Paul estimated its length at 9 meters (30 ft) and its weight at 2.5 tonnes (2.75 short tons). In 2016 it was given a smaller size of 7.5 meters (24.6 ft) and 1.2 tonnes (1.3 short tons). The preserved cranial elements include the premaxillae, dentary, and anterior portions of the maxillae and nasals.
|
|
The smooth narial fossae are located just behind these, and help to give the snout its broad flattened look. The maxillae are, by quite a long way, the largest and most expansive bones in the skull; each holds nineteen small recurved teeth. They have a narrow alveolar margin at the edge of their broad expanse, giving the head of Anatosuchus a rather rectangular appearance, and broad rami that extend above and below the antorbital opening. The upper of these rami form a long suture with the nasal, and then meet the prefrontal and lacrimal directly above the antorbital fenestra.
|
|
In arthropods, cephalization progressed with increasing incorporation of trunk segments into the head region. This was advantageous because it allowed for the evolution of more effective mouth-parts for capturing and processing food. Insects are strongly cephalized, their brain made of three fused ganglia attached to the ventral nerve cord, which in turn has a pair of ganglia in each segment of the thorax and abdomen. The insect head is an elaborate structure made of several segments fused rigidly together, and equipped with both simple and compound eyes, and multiple appendages including sensory antennae and complex mouthparts (maxillae and mandibles).
|
|
Cyriopagopus schmidti resembles C. hainanus, but can be distinguished by its dark yellow-brown body and the shorter length of the "thorns" on the forward- facing (prolateral) sides of the maxillae. The carapace (upper surface of the cephalothorax) is dark yellow-brown; the abdomen is similarly coloured, with black stripes running across it and a black stripe down the centre of the upper surface. The female has been described as one of the largest Asian spiders, and is said to be able to live up to 30 years. It is between 53 and 85 mm long (body plus chelicerae).
|
|
Cyriopagopus hainanus resembles C. schmidti, but can be distinguished by its dark black-brown body and the longer "thorns" on the forward-facing (prolateral) side of the maxillae. The carapace (upper surface of the cephalothorax is black-brown, the sternum (under surface of the cephalothorax) is red-brown; and the abdomen is dark brown, with six black stripes running across it and a black stripe down the centre of the upper surface. The female is about 60 mm long (body plus chelicerae). The first leg is longest, at about 67 mm, the third being the shortest, at about 51 mm.
|
|
Life reconstruction of Pseudochampsa ischigualastensis The type species of Pseudochampsa was originally thought to be a member of Chanaresuchus. Trotteyn et al. (2012) referred this species to Chanaresuchus and diagnosed Chanaresuchus based on the presence of cranial ornamentation by longitudinal crests and depressions on the upper surfaces of the premaxillae, maxillae and nasal bones, a side fossa on the centrum of the presacral vertebrae, a low deltopectoral crest on the humerus, and the absence of a fifth toe. However, Trotteyn and Ezcurra (2014) revised these supposed synapomorphies of Chanaresuchus and found them to represent synapomorphies of larger clades.
|
|
Occlusion according to The Glossary of Prosthodontic Terms Ninth Edition is defined as 'the static relationship between the incising or masticating surfaces of the maxillary or mandibular teeth or tooth analogues'. When exploring different complete denture occlusal schemes, it is more useful to define occlusion as the relative movement of one object to another viz the dynamic relationship between mandible to the maxillae during function. Bilateral balanced occlusion and non-balanced occlusion are two separate entities that make up complete denture occlusion. Bilateral balanced occlusion is observed when simultaneous contacts achieved in both centric and eccentric positions.
|
|
Apparently, there was niche partitioning among species, such is the case of high browser therizinosaurids Erlikosaurus and Segnosaurus, or the grazer Talarurus and browser Tsagantegia. Erketu, a long necked sauropod from the formation, may have been the tallest herbivore. While other dromaeosaurids filled a variety of specialized ecological niches like the slender unenlagiines, Achillobator retained a conservative life-style and filled the niche of large-bodied predator of often medium to large-sized prey. The re-examination of the maxillae in eudromaeosaur taxa indicates that Asian and North American eudromaeosaurs were separated by snout morphology and ecological strategies.
|
|
The submaxillary space is a historical term for the combination of the submandibular, submental and sublingual spaces, which in modern practice are referred to separately or collectively termed the perimandibular spaces. The term submaxillary may be confusing to modern students and clinicians since these spaces are located below the mandible, but historically the maxilla and mandible together were termed "maxillae", and sometimes the mandible was termed the "inferior maxilla". Sometimes the term submaxillary space is used synonymously with submandibular space. Confusion exists, as some sources describe the sublingual and the submandibular spaces as compartments of the "submandibular space".
|
|
The palate of Labidosaurikos shares a general resemblance to the captorhinid pattern however; there are some specializations that come with the presence of multiple rows of teeth. Some of these features include transverse constriction of the palate by medially expanding tooth laminae of the maxillae and the loss of teeth from the palatine and anterior process of the pterygoid. The vomer is exceptionally slender, long and smoothly convex anteriorly which is a trait shared by Moradisaurus. The anteroventrally directed premaxillae which contain five long premaxillary teeth that decrease in size posteriorly as is the case in other captorhinids.
|
|
Each side of the tip of the upper jaw had four teeth, while the maxillae (main tooth-bearing bone of the upper jaw) and dentaries (tooth- bearing bone of the lower jaw) had twelve or thirteen each. The thigh bones were slender, and there were bony scutes on both the back and belly. The scutes on the upper surface were arranged in two rows running the length of the animal. Clark and Sues performed a phylogenetic analysis and found Kayentasuchus to have an unresolved position along with several other sphenosuchians, neither closer to true crocodiles or to Sphenosuchus.
|
|
A lower right left Cranial bones recovered from the Manda Beds consist of a badly crushed orbito-ethmoidal region, a practically complete right mandible, two fragments of the left mandible, several loose teeth, a portion of the occiput, and several unidentified fragments. In the upper jaw, only the posterior ends of the maxillae, a portion of the palate, and the floor of the orbits are well preserved. The maxillary postcanines are transversely ovate and have three main cusps arranged upon the same transverse plane. The three main cusps are composed of the lingual, central, and labial cusp.
|
|
Maxillae, premaxillae, palatines, and a vomer along with large skull fragments from Pavāri have been identified as Ventastega. The maxilla is long and low, and unlike some fish, the posterior third of the maxilla is the lowest part of the bone. The teeth on the maxilla are approximately equal in size to each other, except for teeth in the posterior part where they shrink in size. The presence of a coronoid fangs in Ventastega is a primitive feature lost in Ichthyostega, Acanthostega, and likely Tulerpeton, indicating that Ventastega was more basal on a phylogeny in comparison other tetrapods.
|
|
The septal nasal cartilage (cartilage of the septum or quadrangular cartilage) is composed of hyaline cartilage. It is somewhat quadrilateral in form, thicker at its margins than at its center, and completes the separation between the nasal cavities in front. Its anterior margin, thickest above, is connected with the nasal bones, and is continuous with the anterior margins of the lateral cartilages; below, it is connected to the medial crura of the major alar cartilages by fibrous tissue. Its posterior margin is connected with the perpendicular plate of the ethmoid; its inferior margin with the vomer and the palatine processes of the maxillae.
|
|
When ready to emerge from the water, nymphs vary in length, depending on species, from . The head has a tough outer covering of sclerotin, often with various hard ridges and projections; it points either forwards or downwards, with the mouth at the front. There are two large compound eyes, three ocelli (simple eyes) and a pair of antennae of variable lengths, set between or in front of the eyes. The mouthparts are designed for chewing and consist of a flap-like labrum, a pair of strong mandibles, a pair of maxillae, a membranous hypopharynx and a labium.
|
|
An opisthoglyphous snake. A hognose snake skull (Heterodon nasicus)Opisthoglyphous ("rearward grooves") snakes possess venom injected by a pair of enlarged teeth at the back of the maxillae, which normally angle backward and are grooved to channel venom into the puncture. Since these fangs are not located at the front of the mouth, this arrangement is vernacularly called "rear-fanged". In order to envenomate prey, an opisthoglyphous snake must move the prey into the rear of its mouth and then penetrate it with its fangs, presenting difficulties with large prey although they can quickly move smaller prey into position.
|
|
Skeletal diagram The braincase of Piatnitzkysaurus has been reviewed in detail by Oliver Rauhut; the review constitutes one of the few detailed accounts of braincase morphology in basal theropods. Piatnitzkysaurusis the only member of Piatnitzkysauridae with cranial material preserved, for which two maxillae, a frontal, a braincase, and a partial dentary are known. Piatnitzkysaurus is among the most basal members of the tetanurans and is important for understanding not only Middle Jurassic theropod evolution in the Southern Hemisphere, but also for knowledge of character evolution at the base of tetanurae. The braincase of the holotype of Piatnitzkysaurus floresi (PVL 4073) is rather well preserved and shows no signs of deformation.
|
|
While Erpetosuchus and Parringtonia had unserrated and only slightly mediolaterally compressed teeth, Tarjadia had thin and serrated teeth more similar to other carnivorous archosauriforms. Erpetosuchids also had broad maxillae with antorbital fenestrae set approximately in the middle of the deep antorbital fossa, which in turn was completely surrounded by bony ridges. Under the ridge which composes the ventral edge of the antorbital fossa, the maxilla (particularly the rear part) slopes inwards towards the teeth. Although erpetosuchid skulls were not low and flat like those of some archosauriform groups, they were broader than those of other basal pseudosuchians, particularly behind the orbits, which were large and pointed upwards.
|
|
Maxillae The maxillary dorsal process may have been slenderly built, and is similar in some respects to the observed anatomy in Oromycter. A modest anterodorsal process of the maxilla, is present at the level of the internal narial border of the bone medially. The dorsal terminus is broken in the more complete maxillary fragment, making it difficult to determine its original height. In contrast to Oromycter, the preserved base of the narial border of the dorsal process is wide and rounded, suggesting that an anterior maxillary shelf may have been present on the complete maxilla, the shape of the maxilla in this region also suggests that there may have been one.
|
|
The maxillae and labium are adapted to manipulating the algae the larvae feed on, while the mandibles contain a channel through which fluids are sucked out of the food. The larval legs are short and carry a single claw each, but the forelegs have various adaptations for climbing among water plants. Respiration is via gills which are either long and filamentous, or (in Peltodytes) short microtracheal extensions; they are carried on the tergites of all sternal and all but the tenth (last) abdominal segments. The latter may be absent, but in the larvae of some Haliplidae it is tapering and ends in two prongs (which are not urogomphi though).
|
|
The rostrum of Oxalaia features broad, deep (holes) that are possibly nutrient canals for blood vessels and nerves; it is also rounder in side view than that of Spinosaurus, whose upper jaw ends in a more acute downward angle as shown by specimens MSNM V4047 and MNHN SAM 124. The maxillae show a pair of elongated and thin processes extending forwards along the midline of the roof of the mouth; they are encased between the praemaxillae and border an elaborate, triangle-shaped pit at their front end. Similar processes are present in Suchomimus, Cristatusaurus, and MNHN SAM 124, although not as exposed. These structures compose the animal's secondary palate.
|
|
It consists of two upper jawbones, left and right maxillae. Maleev erroneously assumed these represented the lower jaws. Referred was specimen PIN 554/2-1, the rear of the skull of another individual. In 1977, Teresa Maryańska noted a similarity with another Mongolian ankylosaur, Talarurus, in that both taxa have separate openings for the ninth to twelfth cerebral nerve; she therefore renamed the species as Talarurus disparoserratus.T. Maryańska, 1977, "Ankylosauridae (Dinosauria) from Mongolia", Palaeontologia Polonica 37: 85-151 Having determined that Syrmosaurus is a junior synonym of Pinacosaurus, Soviet palaeontologist Tatyana Tumanova named the material as a new genus Maleevus in honor of Maleev in 1987.
|
|
The skull of Yarasuchus is poorly represented, known from only a few isolated pieces. A number of bones were initially identified by Sen (2005), including a jugal, quadrate and part of the quadratojugal, squamosal, both pterygoids and two maxilla that included a portion of premaxilla attached to one of them, as well as an associated tooth. However both maxillae differ from the known maxilla in Teleocrater and instead more closely resemble those of an allokotosaur. Nesbitt and colleagues also regarded the jugal, quadrate and quadratojugal as indeterminate bones, and re- identified the squamosal as a postorbital belonging to a larger individual than the holotype specimen.
|
|
No teeth were present along the premaxillae or the rostral area of the maxillae, but four crushing teeth were in each side of the palate, the first three in a triangle of small, rounded teeth and the fourth a short distance behind them. The fourth tooth was huge, far larger than the first three. The lack of teeth near the front of the mouth and rostrum indicate that the elongated rostrum was mainly used for rooting out or digging up shellfish, which would then be taken into the back of the mouth and crushed by the large teeth. Psephoderma's temporal fossae were narrow, but highly elongated.
|
|
The prothorax forms a slender mobile "neck" for the large, square, flattened head, which bears an enormous pair of sickle-like jaws with several sharp, hollow projections. The jaws are formed by the maxillae and mandibles; the mandibles each contain a deep groove over which the maxilla fits neatly, forming an enclosed canal for injecting venom to immobilise the victim, and enzymes to digest its soft parts. The larva is clad in forward-pointing bristles which help it to anchor itself and exert greater traction, enabling it to subdue prey considerably larger than itself. Antlion larvae are unusual among insects in lacking an anus.
|
|
The teeth of both the upper and lower jaws are small and cone-shaped, some having slightly serrated edges, and are only differentiated by slight differences in length (some other synapsids have teeth that vary greatly and shape across their jaws). The three forward- most dentary teeth are angled slightly outward as in more derived synapsids such as Dimetrodon and Sphenacodon. Several features, including straight- margined maxillae and simple conical teeth, are also seen in the earliest reptiles. Twenty-three presacral (neck and back) vertebrae are preserved in the holotype, although several may be missing because the typical number of presacral vertebrae in early synapsids is 27.
|
|
The first fingers were large, being both longer and thicker than either of the bones of the forearm. The teeth differed slightly (they were heterodont) based on position: those near the tips of the upper jaws (on the premaxillae) were slender and lacked serrations, while those behind them (on the maxillae) were serrated and laterally compressed. The teeth of the lower jaws were similarly differentiated. A pigmented area in the abdomen of the holotype has been suggested as possible traces of organs, and was interpreted as the liver by John Ruben and colleagues, which they described as part of a crocodilian-like "hepatic piston" respiratory system.
|
|
The platypus has an average body temperature of about rather than the typical of placental mammals. Research suggests this has been a gradual adaptation to harsh environmental conditions on the part of the small number of surviving monotreme species rather than a historical characteristic of monotremes. Modern platypus young have three teeth in each of the maxillae (one premolar and two molars) and dentaries (three molars), which they lose before or just after leaving the breeding burrow; adults have heavily keratinised pads in their place. The first upper and third lower cheek teeth of platypus nestlings are small, each having one principal cusp, while the other teeth have two main cusps.
|
|
These fangs are articulated so that they can extend downward and outward in preparation to bite or can fold back toward the chelicerae as a pocket knife blade folds back into its handle. The chelicerae of a tarantula completely contain the venom glands and the muscles that surround them, and can cause the venom to be forcefully injected into prey. The pedipalpi are two six-segmented appendages connected to the prosoma near the mouth and protruding on either side of both chelicerae. In most species of tarantulas, the pedipalpi contain sharp, jagged plates used to cut and crush food often called the coxae or maxillae.
|
|
Since Velociraptor was the first to be named, these species were renamed Velociraptor antirrhopus and V. langstoni. However, the only currently recognized species of Velociraptor are V. mongoliensis and V. osmolskae. Size of Velociraptor (2) compared with other dromaeosaurs Maxillae of V. osmolskae and V. mongoliesis compared Diagram of the V. mongoliensis type skull and the associated claw from 1924 When first described in 1924, Velociraptor was placed in the family Megalosauridae, as was the case with most carnivorous dinosaurs at the time (Megalosauridae, like Megalosaurus, functioned as a sort of 'wastebin' taxon, where many unrelated species were grouped together). As dinosaur discoveries multiplied, Velociraptor was later recognized as a dromaeosaurid.
|
|
Several features indicate that Smok is an archosaur, including serrated teeth, a contact between the jugal and quadratojugal bones at the back of the skull, a hole in front of the eye socket called the antorbital fenestra, maxillae bones in the upper jaw that connect along their palatal processes, and a rounded projection on the upper part of the femur bone. The braincase of Smok includes many derived (advanced) features. The most prominent of these is a funnel-shaped structure on the bottom of the braincase, formed by a very wide, rounded basisphenoid bone. A deep notch called the basisphenoid recess cuts into the back of this funnel.
|
|
The position of the mouth and the circum-oesophageal connectives allows a distinction to be made between pre- and post-oral structures; although it should be borne in mind that because structures can move around during development, a pre-oral position of a structure in the adult does not necessarily prove that its developmental origin is from there. The myriapod head is very similar to that of the insects. The crustacean head is broadly similar to that of the insects, but possesses, in addition, a second pair of antennae that are innervated from the tritocerebrum. In place of the labium, crustaceans possess a second pair of maxillae.
|
|
Reconstructed skull, Museum of Ancient Life, Utah Unlike most giant theropod dinosaurs, Suchomimus had a very crocodilian-like skull, with a long, low snout and narrow jaws formed by a forward expansion of the (frontmost snout bones) and the hind branch of the (main upper jaw bone). The praemaxillae had an upward branch excluding the maxillae from the (bony nostrils). The jaws had about 122 conical teeth, pointed but not very sharp and curving slightly backwards, with fine serrations and wrinkled enamel. The tip of the snout was enlarged sideways and carried a "terminal rosette" of longer teeth, seven per side in the premaxillae and about the same number in the corresponding part of the lower jaw.
|
|
The holotype, AODF 876, was found in a layer of the Winton Formation dating from the Cenomanian - lower Turonian, about ninety-six million years old. It consists of a partial skeleton with skull and lower jaws. It contains the front part of the head with the premaxillae, the maxillae and the dentaries; the left frontal bone, the rear part of the left lower jaw; forty single teeth; five neck vertebrae; the right shoulder joint; the left ulna; the left radius; the proximal and distal left wrist bones; two fourth metacarpals; phalanges from the first to third fingers of the left hand; and the first phalanx of the fourth finger. It represents a fully-grown but not yet mature animal.
|
|
Life restoration of the cochleosaurid Chenoprosopus milleri Edopoids are relatively large temnospondyls, with many species estimated to have grown several meters in length. The skull of Edops is broad while those of cochleosaurids are narrower and elongated. Distinguishing features of edopoids include the presence of an intertemporal bone that is absent in all other temnospondyls, and the lack of a pineal foramen, a small hole on the skull roof of many early tetrapods (young individuals still possess this hole). Relative to other temnospondyls, edopoids also have enlarged premaxillae, maxillae, and nasal bones in the snout region, which constrict the nostrils to small holes and push them to the sides of the skull.
|
|
There were five teeth in both of the bones that made up the tip of the snout (premaxilla), fifteen in the paired maxillae that formed the sides of the upper jaw, and twenty in both dentaries of the lower jaw. The front of the lower jaw had a flattened shape, and the teeth located here pointed partially forward, with a spade-like form. The teeth had variable shapes; the first thirteen teeth in the lower jaw were pointed, while the last seven graded from a spatulate shape to a large globular shape. Aside from the horns, the skull and particularly the lower jaw of Ceratosuchus were very similar to that of its contemporary Allognathosuchus.
|
|
Tooth, 203x203px The teeth of D. orgosense (from which that species is mainly known) are 25 percent larger than those of Paraceratherium transouralicum, indicating that it was one of the largest known indricothere,Prothero, 2013. pp. 67–86 but the teeth and skull was proportionally large compared to the body, making it smaller overall. Paraceratherium bugtiense and D. orgosense share features such as relatively slender maxillae and premaxillae, shallow skull roofs, mastoid-paroccipital processes that are relatively thin and placed back on the skull, a lambdoid crest, which extends less back, and an occipital condyle with a horizontal orientation. D. orgosense is distinguished from Paraceratherium species by the larger size of its teeth, and distinct crochets of its molars.
|
|
This suggestion was refuted by François-Xavier Gauffre in 1993 when he re-described the material, as well describing additional jaw bones and teeth including two maxillae. He correctly concluded that the material belonged to a single taxon, but assigned the genus to "Prosauropoda" incertae sedis based again on the characteristics of the jaws and teeth. However, he could not determine its position within "Prosauropoda" due to the ambiguous distribution of these traits in early herbivorous dinosaurs, as well as a lack of any comparable Triassic reptiles, so he referred it to incertae sedis. His assessment was accepted by many other researchers in the years following up until the description of the new material from the Madagascan species.
|
|
Tethysaurus is the type genus, as it is the best-represented genus of the subfamily, known from multiple partial skeletons. Thus the subfamily name derives from the name of its type genus. Pannoniasaurus is known from various material, including 2 isolated premaxillae, 3 maxillae, 2 postorbitofrontals, 2 quadrates, 3 dentaries, 3 splenials, 3 angulars, a coronoid, 2 surangulars, an articular, 91 isolated teeth, 20 cervical, 40 dorsal, 4 sacral, and 18 caudal vertebrae, 34 vertebral fragments, 3 ribs, 2 humeral fragments, and 4 ilia. Since all remains are isolated bones, the basis for the referral of this material to Pannoniasaurus is based on similar methods used by other authors, such as Houssaye et al.
|
|
Both head and thorax are clad in short hairs, but no bristles are on the body. The membranous forewings are clear, uniformly shaded grey or brown, or patterned in some species; they have a basal lobe (or calypter) that covers the modified knob-like hindwings or halteres. The tips of the legs have two lobes on the sides (pulvilli) and a central lobe or empodium in addition to two claws that enable them to grip surfaces. Species recognition is based on details of head structures (antennae, frons, and maxillae), the wing venation and the body patterning; minute variations of surface structure cause subtle alterations of the overlying hairs which alters the appearance of the body.
|
|
Steppan, 1996, p. 523 The material Riggs collected includes nine mandibles, three maxillae, and five isolated molars. The specific name Steppan gave to the animal, primigenus, means "primitive" in Latin and refers to the primitive features of the animal when compared to its relatives Holochilus and Lundomys.Steppan, 1996, p. 524 In order to determine the relationships of his new species, Steppan carried out a cladistic analysis, in which he also included the oryzomyines Holochilus, Lundomys, Pseudoryzomys, and Cerradomys, as well as the non- oryzomyine Sigmodon.Steppan, 1996, table 2; Weksler et al., 2006, for nomenclature His results supported a close relation between R. primigenus and extant Holochilus, with Lundomys and Pseudoryzomys more distantly related.
|
|
The same year, Hans- Dieter Sues and colleagues regarded both Cristatusaurus and Suchomimus as junior synonyms of Baryonyx, stating that there is no fossil evidence indicating more than one spinosaur lived in the Elrhaz Formation. More recent research has retained Suchomimus and Baryonyx as distinct genera. Others, such as Bertin Tor in 2010, and Carrano and colleagues in 2012, have referred to Cristatusaurus as an indeterminate baryonychine, because of how fragmentary its remains are. In 2016, Christophe Hendrickx, Octávio Mateus, and Buffetaut noted that Taquet and Russel might have interpreted Cristatusaurus as having a shorter snout than Baryonyx by mistaking the notch where the maxillae articulated with the premaxillae for the nostril openings.
|
|
"Biscoveosaurus" is the informal name of an ornithopod dinosaur specimen from the Early Maastrichtian age Snow Hill Island Formation of James Ross Island, Antarctica. It comes from the Cape Lamb Member of the formation, the same member as Morrosaurus, another basal ornithopod. As such, it's been suggested it may be a secondary specimen of that species, but as the holotype of Morrosaurus is fragmentary and doesn't overlap with the material of "Biscoveosaurus", this can't as yet be tested. The specimen consists of dentaries, teeth, a braincase, parts of the maxillae, forelimb elements, assorted vertebrae, and the pectoral girdle; this makes it unique compared to the other James Ross Island ornithopods, which don't presever both cranial and postcranial remains.
|
|
The most famous case is of Novemthree Siahaan (who died on September 15, 2005), a young Indonesian boy from Batam Island who received medical care in Haulien, Taiwan through a Buddhist missionary from the Tzu Chi Foundation, which was documented on the Discovery Health Channel. Another famous case is a young Korean girl named Ayun Lee (August 26, 2003~) and her father Young-hak Lee whose case has shown that the tumor can be heritable. She is currently under treatment, which she may need to continue until her growth stops in her early 20s. The term has been used in the past to describe florid cemento-osseous dysplasia, but it is now reserved for an autosomal dominant condition affecting the maxillae.
|
|
Raeticodactylus had a tall thin bony crest running along the midline of the front of the upper jaw, and a keel on the lower jaw; however, it does not seem to be closely related to Austriadactylus, the only other crested Triassic pterosaur named by the time Raeticodactylus was described. The teeth at the front of the upper jaw, in the premaxillae, were fanglike, whereas the teeth in the upper cheeks (the maxillae) had three, four, or five cusps, similar to those of Eudimorphodon. Raeticodactylus had a wingspan of about 135 centimeters (53 in), and may have been a piscivore, potentially feeding by skimming the water. However, skim-feeding has since been disproven in pterosaurs, and the related Caviramus appears to have been an omnivore.
|
|
The total number of fossils recovered from both expeditions at the dig sites included a temporal bone, three partial mandibles, two partial maxillae, and forty four teeth, but it was the skull dubbed KNM-WT 40000 that sparked the most scientific interest because of its relative completeness (Leakey 2001). This skull had many characteristics that had been seen before in other specimens, however the combination of features had never been seen before; this led scientists to realize that this was indeed a separate and unique species. KNM-WT 40000 and the other bones were collected from a dark mudstone, which contained volcanic pebbles and solidified CaCO3. The mudstone was located in between the Lokochot Tuff and the Tulu Bor Tuff in the Kataboi Member.
|
|
Mixed dentition stage starts when the first permanent tooth appears in the mouth, usually at five or six years with the first permanent molar, and lasts until the last primary tooth is lost, usually at ten, eleven, or twelve years. There are 32 permanent teeth and those of the maxillae erupt in a different order from permanent mandibular teeth. Maxillary teeth typically erupt in the following order: (1) first molar (2) central incisor, (3) lateral incisor, (4) first premolar, (5) second premolar, (6) canine, (7) second molar, and (8) third molar. Mandibular teeth typically erupt in the following order: (1) first molar (2) central incisor, (3) lateral incisor, (4) canine, (5) first premolar, (6) second premolar, (7) second molar, and (8) third molar.
|
|
Dorsal (left) and ventral (right) views of the holotype of Kiwa puravida (Kiwaidae); two pereiopods have broken off on the animal's left side. The cephalothorax is made of 13 body segments (somites), although the divisions are not obvious and are most easily inferred from the paired appendages. From front to back, these are, the two pairs of antennae, six pairs of mouthparts (mandibles, maxillae, maxillules and three pairs of maxillipeds), five pairs of pereiopods. The cephalothorax is covered with a thick carapace, which may extend forwards in front of the eyes to form a rostrum; this is highly variable among squat lobsters, being vestigial in Chirostylus, wide and often serrated in some genera, and long, narrow, and flanked with "supraorbital spines" in others.
|
|
It contains both praemaxilla (frontmost upper jaw bones), both maxillae (main upper jaw bone), teeth, a lacrimal, a jugal, a postorbital, a squamosal, a supraoccipital, parts of the lower jaws, a possible hyoid, two cervical (neck) vertebrae (backbones), cervical ribs, rear dorsal (back) vertebrae, at least five front caudal (tail) vertebrae, chevrons, ribs, gastralia (or "belly ribs"), the lower parts of a left forelimb, a furcula (wishbone), both pubic bones, a left ischium (lower and rearmost hip bone), a right femur, a tibia (shin bone), the upper part of a fibula (calf bone), a left astragalus (ankle bone), three tarsals, and three metatarsals. About 40% of the skeleton is presented. Dracoraptor is thus the most complete Mesozoic non-bird theropod dinosaur known from Wales.
|
|
Along with the width of the frontal bone (a bone at the top of the skull), this appeared to have made the rear part of Lythronaxs skull very broad, with orbits (eye sockets) that faced nearly forwards. These features are otherwise only known in Tarbosaurus and Tyrannosaurus; earlier-diverging tyrannosaurids had less forward-facing orbits, and the rears of their skulls were narrower. Lythronax was also distinct in that the surfaces of the frontal bone that contacted the prefrontal and postorbital bones at its front and rear sides were separated by only a narrow groove. The maxillae of Lythronax were robust and strongly convex along their outer margins, as in all other known tyrannosaurids, but differed in their sigmoid-shaped margins.
|
|
Reconstruction of the youngest and most mature skulls The type species D. priscus is known from the holotype KU 11117, a fragmentary left maxilla bearing 4 teeth, and from the fragmentary referred specimens KU 11118 and KU 11119, a right and a left maxillae respectively, each bearing 4 teeth. All known specimens of D. priscus are housed at the University of Kansas Natural History Museum in Lawrence, Kansas. Unlike the type species, D. cifellii is known from a well-preserved partial subadult skeleton, an isolated adult skull, and other disarticulated elements, all housed at the Oklahoma Museum of Natural History. The subadult individual preserves both the partial skull and the postcranial remains in articulation, and thus was chosen as the holotype, represented by OMNH 73515\.
|
|
Godefroit and colleagues assigned additional remains from the bonebed to their new genus, including three braincases, a cheekbone, two maxillae (the toothbearing bone of the upper jaw), another dentary, two shoulder blades, two sternal elements, two upper arm bones, and an ischium. It can be distinguished from other hadrosaurids by its slender dentary and the unique form of its upper arm, which had distinctive articulations and placements for muscle attachments. Godefroit and colleagues performed a phylogenetic analysis that suggests Wulagasaurus was the most basal saurolophine known (which would result in a long ghost lineage), and interpreted this as evidence that saurolophines and hadrosaurids in general originated in Asia, which has been supported by other finds since. As a hadrosaurid, Wulagasaurus would have been an herbivore.
|
|
The type species D. serratus was, and still is, based solely on two partial maxillae with a few teeth, cranial fragments, and a dozen vertebrae with some additional material, collected but not described by Gibbes, and referred to the type species. Before Uhen 2004, D. atrox was based solely on Andrews holotype skull, lower jaw, and the vertebrae he referred to it, but is now the best known archaeocete species. The two species of Dorudon differ from other members of Dorudontinae mainly in size: they are considerably larger than Saghacetus and slightly larger than Zygorhiza, but also differ from both these genera in dental and/or cranial morphology. The limited known material for D. serratus makes it difficult to compare the two species of Dorudon.
|
|
Hexapods have bodies ranging in length from 0.5 mm to over 300 mm which are divided into an anterior head, thorax, and posterior abdomen. The head is composed of a presegmental acron that usually bears eyes (absent in Protura and Diplura), followed by six segments, all closely fused together, with the following appendages: :Segment I. None :Segment II. Antennae (sensory), absent in Protura :Segment III. None :Segment IV. Mandibles (crushing jaws) :Segment V. Maxillae (chewing jaws) :Segment VI. Labium (lower lip) The mouth lies between the fourth and fifth segments and is covered by a projection from the sixth, called the labrum (upper lip). In true insects (class Insecta) the mouthparts are exposed or ectognathous, while in other groups they are enveloped or endognathous.
|
|
It contains the right premaxilla, both maxillae, the left jugal, a part of the right lacrimal, the rear of a left nasal bone, the middle part of a right nasal bone, the skull roof from the frontal bones to the exoccipitals, both squamosals, both quadrate bones, the predentary of the lower jaws, both dentaries, a right surangular, eleven neck vertebrae, eleven back vertebrae, twenty-nine tail vertebrae, nineteen chevron bones, nineteen ribs, the entire pelvis, both lower legs, a right second metatarsal and a right fourth metatarsal. The bones have not been found in articulation. Specimen MOR 1097, a fragmentary skull of a subadult individual, was referred to the species. It had been found at a kilometre distance from the holotype.
|
|
The pair of large compound eyes almost touch in the male, but are more widely separated in the female. They have three simple eyes (ocelli) and a pair of short antennae. Houseflies process visual information around seven times more quickly than humans, enabling them to identify and avoid attempts to catch or swat them, since they effectively see the human's movements in slow motion with their higher flicker fusion rate. Housefly mouthparts, showing the pseudotracheae, semitubular grooves (dark parallel bands) used for sucking up liquid food The mouthparts are specially adapted for a liquid diet; the mandibles and maxillae are reduced and not functional, and the other mouthparts form a retractable, flexible proboscis with an enlarged, fleshy tip, the labellum.
|
|
Further back, there were at least 22 teeth per upper jaw side in the maxilla, while the entire lower jaw side carried 32 teeth in the dentary bone. Closeup of front of the snout and dentition The upper jaw had a prominent kink just behind the rosette, protruding downwards; this convexly curved part of the maxilla had the longest teeth of the entire skull. The internal bone shelves of the maxillae met each other in the midline of the skull over a long distance, forming a closed secondary palate that stiffened the snout, and setting off the internal nostrils and palatal complex (including the pterygoid, palatine and ectopterygoid) towards the back of the skull. The nostrils, unlike in most theropods, were retracted further back on the skull and behind the premaxillary teeth.
|
|
Several single bones and teeth found in other American sites have been referred to Torvosaurus. Maxillae of T. gurneyi and T. tanneri compared In 1992, fossils of a large theropod found at Como Bluff in Wyoming, containing skull, shoulder girdle, pelvis and rib elements, were named by Robert T. Bakker et al. as the species Edmarka rex. Bakker et al were impressed with the size of Edmarka, noting that it "would rival T. rex in total length," and viewing this approximate size as "a natural ceiling for dinosaurian meat-eaters."Bakker, R.T., Siegwarth, J., Kralis, D. & Filla, J., 1992, "Edmarka rex, a new, gigantic theropod dinosaur from the middle Morrison Formation, Late Jurassic of the Como Bluff outcrop region", Hunteria, 2(9): 1–24 This was often considered a junior synonym of Torvosaurus.
|
|
The skull is approximately 5 – 7 mm in length with reduced kynesis and a more rigid skull for burrowing. The combination of fossorial habits and small size, contributes to the development of a skull configuration that is frequently found in other groups of burrowers and miniaturized species. Among those characteristics are the closure of the supratemporal fenestra and the post-temporal fenestra, the relative large braincase, tubular or scroll-like palatines and modified jaw suspension mechanism with the quadrate articulating with the lateral wall of the braincase. Other characteristics of the skull of blind skinks include the absence of a parietal foramen, a well developed secondary palate formed by three different bones, the maxillae, vomers and palatines which are expanded ventromedially to form a scroll, and the lack of palatal teeth.
|
|
Even completely lyophilized human mandibles were used successfully in patients. In 1989, Sailer was the first to describe the use of dental implants simultaneously with the reconstruction of the atrophic maxilla.Sailer, H.F., A New Method of Inserting Endosseous Implants in Totally Atrophic Maxillae, in: J. Cran-Max-Fac Surgery Nr. 17, 1989, p. 299 Between 1992 and 2001 Sailer published several works on the production and application of bone-regenerating proteins (bone morphogenetic proteins) in collaboration with his colleagues Edit Kolb und Franz Weber. These proteins were designed to save the patient from undergoing an operative removal of the bone during reconstruction surgery in the region of the jaws and the faceSailer, H.F. & Weber F.E., Gewebsersatz durch die Anwendung von Bone morphogenetic proteins, in: Nova Acta Leopoldina Nr. 32, 2001, p.
|
|
The lips were once believed to be unable to function as a sucker while respiration continued, as the inflowing water would cause the system to fail; however, respiration and suction can function simultaneously. Inflowing water passing under the sucker is limited to a thin stream immediately behind each maxillary barbel; the maxillae in loricariids support only small maxillary barbels and are primarily used to mediate the lateral lip tissue in which they are embedded, preventing failure of suction during inspiration. To achieve suction, the fish presses its lips against the substrate and expands its oral cavity, causing negative pressure. Also, unlike most other catfishes, the premaxillae are highly mobile, and the lower jaws have evolved towards a medial position, with the teeth pointed rostroventrally; these are important evolutionary innovations.
|
|
Teeth The fossil material consists of dentaries and maxillae, hence the characters mentioned by the name Lycorhinus angustidens that Sidney H. Haughton attributed to the remains in 1924, where the generic name means "wolf snout", as it was at first misidentified as a cynodont, and the specific descriptor means "constricted tooth".S.H. Haughton, 1924, "The fauna and stratigraphy of the Stormberg Series", Annals of the South African Museum 12: 323-497 The holotype, SAM 3606, consists of a mandible found by Dr M. Ricono. Three other species of Lycorhinus have been named. Lycorhinus parvidens was created by Robert Broom and Lycorhinus tucki by Richard Anthony Thulborn in 1970 renaming Heterodontosaurus tucki,R.A. Thulborn, 1970, "The systematic position of the Triassic ornithischian dinosaur Lycorhinus angustidens", Zoological Journal of the Linnean Society 49: 235-245 but these have failed to find recognition.
|
|
Endocranial reconstruction of AENM 2/121 based on a CT scan. Kundurosaurus is known from holotype AENM 2/921, a partial, disarticulated skull, including a nearly complete braincase (AENM 2/921 1-2), two quadrates (3-4), squamosal (5), postorbital (6), frontal (7) and parietal (8) bones. The referred specimens are AENM 2/45-46, two jugals; AENM 2/83-84, 2/86, maxillae; AENM 2/57-58, nasals; AENM 2/48, postorbital; AENM 2/19, quadrate; AENM 2/121, 2/928 partial braincases; AENM 2/846, 2/902, dentaries; AENM 2/906, scapula; AENM 2/913, sternal; AENM 2/117, 2/903, 2/907-908, humeri; AENM 2/905, ulna; AENM 2/904, radius; AENM 2/922, nearly complete pelvic girdle and associated sacral elements. These were found at the same level as the holotype, but may belong to other individuals.
|
|
In 2010, Benson pointed out that the fragment was basically indistinguishable from other known M. bucklandii maxillae, to which it had in fact not been compared by the other authors. Referred femur in France Apart from the finds in the Taynton Limestone Formation, in 1939 Sidney Hugh Reynolds referred remains to Megalosaurus that had been found in the older Chipping Norton Limestone Formation dating from the early Bathonian, about thirty single teeth and bones. Though the age disparity makes it problematic to assume an identity with Megalosaurus bucklandii, in 2009 Benson could not establish any relevant anatomical differences with M. bucklandii among the remains found at one site, the New Park Quarry, and therefore affirmed the reference to that species. However, in another site, the Oakham Quarry, the material contained one bone, an ilium, that was clearly dissimilar.
|
|
Mantispinae have the most specialized larval development among all mantidflies studied to date (the life history of the Drepanicinae remains unknown): their campodeiform larvae seek out female spiders or their egg sacs which they then enter; the scarabaeiform larvae then feed on the spider eggs, draining egg contents through a piercing/sucking tube formed by modified mandibles and maxillae, pupating in the egg sac. First-instar mantispids use two strategies to locate spider eggs: larvae may burrow directly through the silk of egg sacs they find, or they may board and be carried by female spiders prior to sac production (phoresy), entering the sac as it is being constructed. Mantispids that board spiders usually adopt positions on or near the pedicel; some species may enter the spider's book lungs. Larvae maintain themselves aboard spiders by feeding on spider hemolymph.
|
|
Echinerpeton is known from six specimens, five housed in the Museum of Comparative Zoology and a sixth in the Redpath Museum: the holotype MCZ 4090, which consists of a partial postcranial skeleton and some jaw fragments; MCZ 4091, which includes vertebrae and an interclavicle; MCZ 4092, a left maxilla or upper jaw bone; MCZ 4093, a partial right maxilla; MCZ 4094, including three neural arches or vertebral spines; and RM 10057, consisting of a right maxilla, neural arch, rib, and a phalanx or finger bone. Since all other specimens besides the holotype are isolated bone fragments, their assignment to the same species is not certain. The maxillae are distinct in having straight lower margins, distinct from the often curved jaws of ophiacodontids and sphenacodontids but similar to the straight jaws of some other synapsids like Archaeothyris, Haptodus, and Varanops. The dentary or lower jaw bone has a slight upward curve.
|
|
Achelousaurus thus holds particular importance for being one of the few ceratopsid genera named in the late twentieth century. The holotype specimen MOR 485 was collected by Hostetter and Ray Rogers from the Landslide Butte Field Area about northwest of Cut Bank. In 1995 Sampson described it as the partial skull of an adult animal including the nasal and supraorbital (region above the eye socket) bosses (roundish protuberances instead of horns), and the parietal bones. Additionally, MOR 485 preserves some bones of the skull rear and sides, which in 2009 were listed by Tracy L. Ford as a right squamosal bone, the left squamosal, both maxillae, both lacrimal bones, both quadrate bones, both palatine bones, the braincase and the basioccipital bone. In 2015, Leonardo Maiorino reported that as part of the same specimen a fragmentary lower jaw has been catalogued as MOR 485-7-12-87-4.
|
|
Massetognathus was a medium- sized cynodont, which documents different ontogenetic stages. It had the largest size of any cynodont in the Chañares assemblage with an approximate skull length ranging from the smallest being to the largest . The Middle Triassic Probainognathus and Massetognathus are the earliest non-mammalian cynodonts in the fossil record that show the initial steps of several phylogenetic transformations of the quadrate and can be characterized by several features: The rotation of the dorsal plate relative to the trochlea exhibits a progressively greater rotation more closely related to mammals, squamosal contact and medial expansion of the squamosal were crucial factors in the transforming the quadrate and the articulation of the cranium. The maxillae extend far out dorsally (with a downward slope) to a point about opposite the lower margins of the orbits, then curving downward and inward, present a broad ventral surface lateral to the tooth rows.
|
|
It is perforated by numerous foramina for the passage of the nutrient vessels; is channelled at the back part of its lateral border by a groove, sometimes a canal, for the transmission of the descending palatine vessels and the anterior palatine nerve from the spheno- palatine ganglion; and presents little depressions for the lodgement of the palatine glands. When the two maxillae are articulated, a funnel-shaped opening, the incisive foramen, is seen in the middle line, immediately behind the incisor teeth. In this opening the orifices of two lateral canals are visible; they are named the incisive canals or foramina of Stenson; through each of them passes the terminal branch of the descending palatine artery and the nasopalatine nerve. On the under surface of the palatine process, a delicate linear suture, well seen in young skulls, may sometimes be noticed extending laterally and forward on either side from the incisive foramen to the interval between the lateral incisor and the canine tooth.
|
|
Goronyosaurus hunting juvenile plesiosaurs The clade of Goronyosaurus and Prognathodon, and the other branch with Mosasaurini, were found to be grouped by two unique (unambiguous) features, the lack of frontal bone bordering the nasal opening, and a humerus with a hooked process behind the glenoid cavity. An earlier version of the 2010 analysis found a more typical phylogeny of mosasaurs, with Goronyosaurus closest to Plotosaurus in derived Mosasaurinae, and the clade Plioplatecarpinae resolved, including Ectenosaurus and Prognathodon (the latter typically a mosasaurine). A clade of Goronyosaurus and Plotosaurus was diagnosed by the presence of teeth to the very front of the premaxilla, extension of the tooth row below and behind the orbit, frontally contacting the maxillae, the unforked shape of the contact between skull roof and supratemporal arch bones, location of the vidian canal opening moved posteriorly, absence of zygapophyseal articulations in vertebrae, and complete separation of the deltoid anc pectoral muscle crests on the humerus.
|
|
Little is known about the mandible due to its compression during fossilisation, but the angular had a lateral process just below the facet for attachment which, along with the long articular facet enabling a sliding motion, probably allowed Chimaerasuchus to move its lower jaw back and forth in a chewing motion to grind plant matter. The absence of a posterior buttress on the articular facet indicates that the pterygoideus muscle could have generated horizontal force enabling this chewing to take place. The two roughly conical teeth in each premaxilla would have been used for nipping off plant material or possibly for defence, while the molariform, polycuspid teeth in the maxillae (at least four in each) could have ground up the food. Although the dentary teeth are not known, it is very likely that there was one conical pair at the front which fitted in the gap between premaxilla and maxilla, while the remainder worked with the maxillary teeth to grind, indicating that Chimaerasuchus was almost certainly a herbivore.
|
|
Hadrocodium, whose fossils date from approximately 195 million years ago, in the early Jurassic, provides the first clear evidence of a jaw joint formed solely by the squamosal and dentary bones; there is no space in the jaw for the articular, a bone involved in the jaws of all early synapsids. Fossil of Thrinaxodon at the National Museum of Natural History The earliest clear evidence of hair or fur is in fossils of Castorocauda and Megaconus, from 164 million years ago in the mid-Jurassic. In the 1950s, it was suggested that the foramina (passages) in the maxillae and premaxillae (bones in the front of the upper jaw) of cynodonts were channels which supplied blood vessels and nerves to vibrissae (whiskers) and so were evidence of hair or fur; it was soon pointed out, however, that foramina do not necessarily show that an animal had vibrissae, as the modern lizard Tupinambis has foramina that are almost identical to those found in the nonmammalian cynodont Thrinaxodon. Popular sources, nevertheless, continue to attribute whiskers to Thrinaxodon.
|
|