Great apes, by contrast, have two or three separate and diverging premolar roots.
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A lower jaw bone and upper premolar were found in Greece and Bulgaria, respectively.
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The Luzon premolar teeth also look primitive, but the molars are modern and H. sapiens-like.
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It's all in the distinct premolar teeth, which vary considerably from anything identified in the other species belonging to the Homo genus.
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The Bulgarian premolar dates back some 7.24 million years ago, and the Greek jaw fossil dates back 7.175 million years ago, they said.
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"So they are an all-around 'triple-threat' of a predator, being able to run with their long legs, hunt and cut meat with their sharp teeth, and scavenge with their powerful premolar teeth," he said.
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The two studies, both published in PLOS ONE: The dental study examines specimens of a lower jaw from Greece and an upper premolar from Bulgaria from a relatively new species called Graecopithecus freybergi and concluded they most likely belong to pre-humans called hominin.
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The premolars in humans are the maxillary first premolar, maxillary second premolar, mandibular first premolar, and the mandibular second premolar. Premolar teeth by definition are permanent teeth distal to the canines, preceded by deciduous molars.
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As usual in Hipposideros, the second upper premolar is small and displaced from the toothrow, and the second lower premolar is large.
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The upper premolars have one to two cusps, with the first premolar having only one cusp, a paracone. The second premolar has a paracone and protocone cusp connected by transverse crest. The third premolar has three cusps, paracone, metacone, and protocone, with the metacone and protocone connected by a crista oblique. There is a recorded hypocone on the third premolar.
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Even though the terms are synonymous, "bicuspid" refers to having two functional cusps, and the mandibular first premolar is an example of a premolar with only one functional cusp. Thus, "bicuspid" is technically not as accurate as "premolar". In the universal system of notation, the permanent mandibular premolars are designated by a number. The right permanent mandibular first premolar is known as "28", and the left one is known as "21".
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The Premolar Teeth, hosted by the University of Illinois at Chicago (UIC) website. Page accessed May 16, 2007. The maxillary 1st premolar is also bifurcated with two roots.
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There is always one large buccal cusp, especially so in the mandibular first premolar. The lower second premolar almost always presents with two lingual cusps. The lower premolars and the upper second premolar usually have one root. The upper first usually has two roots, but can have just one root, notably in Sinodonts, and can sometimes have three roots.
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Pont's Analysis is an analysis developed by Pont in 1909. This analysis allows one to predict the width of the maxillary arch at the premolar and molar region by measure the mesio-distal widths of the four permanent incisors. The analysis helps to determine if the dental arch is narrow or normal and if expansion is possible or not. The width from Left Premolar to Right Premolar or Measured Premolar Value (MPV) can be calculated by using Sum of Incisal Widths (S.
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The lingual cusps are well developed and functional, which means the cusps assist during chewing. Therefore, whereas the mandibular first premolar resembles a small canine, the mandibular second premolar is more like the first molar.
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Two premolars in juveniles are replaced by a permanent sectorial premolar.
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Because it was found in enamel, and not dentine, AHSG may have been an additional component in Gigantopithecus which facilitated biomineralisation of enamel during prolonged amelogenesis (enamel growth). In the upper jaw, the third premolar averages in surface area, the fourth premolar , the first and/or second molars (which are difficult to distinguish) , and the third molar . In the lower jaw, the third premolar averages , the fourth premolar , the first/second molars , and the third molar . The molars are the biggest of any known ape.
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In the bottom premolars, the first premolar has one cusp although it can be bicuspid. The second and third premolar generally have 2-3 cusps, although the second bottom premolar has an entoconid and hypoconid and the third bottom premolar in belzebuth has five cusps with a small hypoconulid. Upper molars generally have four cusps although the third molar may not have a hypocone (might even have only two cusps). With the bottom molars, there are generally four cusps and a fifth cusp on the third molar.
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It has three pairs of premolars, with the upper canine much longer than the third premolar. The second premolar is small and slightly intruded from the tooth row (Yasuma, Andau, Apin, Tuh Yit Yu, & Kimsui, 2003).
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Root fracture is a very possible finding in premolar and anterior teeth.
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In some cases this sequence results in simultaneous eruption of canines and first premolar, which may cause an increased distal translation of the permanent canines and possible impaction of first premolars. Enucleation of first premolar buds – it is advocated when first premolar eruption is behind that of canines and second premolars. This allows maximal distal translation of the erupting canines.it is rarely indicated in the maxillary arch.
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Widening of the PDL surrounding the premolar is likely due to secondary oclcusal trauma.
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One of the curiosities of the Ecuadorian Hairless Dog is the absence of premolar teeth.
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The maxillary left first premolar of a dentiform was prepared for all-ceramic crown restoration.
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The holotype preserves all 3 lower molars, and the isolated teeth are: a left first incisor, a right first incisor, a right canine, a right third upper premolar, a left third upper premolar, a right left fourth upper premolar, a left fourth upper premolar, a right first upper molar, a right third upper molar, a left third upper molar, and a left fourth lower premolar. It is debated if great apes evolved in Africa or Eurasia given the abundance of early fossil apes species in the latter and the paucity in the former, despite all modern great apes except the orangutan being known from Africa. The first Miocene African ape, Samburupithecus, was discovered in 1997, and the only others known are Nakalipithecus and Chororapithecus. It is unclear how Nakalipithecus is related to other apes.
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The fossil preserves a bladelike premolar, identified as the fourth premolar, and the piece of the jawbone below it. A diastema (gap) is present between the premolar and the incisor that would have been located in front of it. The alveolus (socket) of the lower incisor extends all the way through the fossil. The p4 bears eight ridges on both sides of the longitudinal crest and is supported by two roots at the front and back.
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Nonetheless, the incisors were likely much broader in KNM-WT 16005. KNM-WT 16005 preserved four cheek teeth on the left side: the third premolar measuring , the fourth premolar measuring , the first molar measuring , and the second molar measuring . The fourth premolar and first molar are a little smaller than those of the Peninj mandible, and the second molar a bit bigger. The KNM-WT 16005 jawbone is smaller than what KNM WT 17000 would have had.
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The lower premolar is tricuspidate and the first and second molars are quadritubercular with a broad cingulum.
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FORL of the lower third premolar Clinical signs of TRs are often minimal since the discomfort can be minor. However, there may be subtle signs of discomfort while chewing, as well as anorexia, dehydration, weight loss, and tooth fracture. The lower third premolar is the most commonly affected tooth.
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A rostral hook is characterized by the first premolar developing a growth that precedes the adjacent tooth. This diagram depicts a rostral hook of the upper first premolar, however a rostral hook can also affect the lower first premolar as well. Rostral hooks occur when the dominant upper front premolars overhang the lower premolars. They can be hereditary or developmental meaning that the horse can have an overbite at birth or can have another malocclusion that forces the disalignment of the jaw.
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As is characteristic of Miniopterus, the first upper premolar (P1) is smaller and more simplified than the second (P2).
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They may also make it difficult during equine dentistry work to rasp the second premolar, and are frequently removed.
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Known material of Dermotherium includes a handful of jaw fragments and isolated teeth. Dermotherium major is known only from a fragment of the left lower jaw bearing the third lower molar (m3) and a poorly preserved second lower molar (m2). The holotype of Dermotherium chimaera is a lower jaw fragment in which remnants of the deciduous third lower premolar are visible. X-ray microtomography reveals the unerupted lower third incisor (i3), canine (c1), third premolar (p3), and fourth premolar (p4) still inside the jaw.
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Lower premolars have smooth enamel set in a relatively deep jaw and the third premolar crown is large and bulbous.
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They had somewhat piglike proportions, short faces, a large upper canine and a caniniform first lower premolar, and selenodont molars.
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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.
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The mandibular second premolar is the tooth located distally from both the mandibular first premolars of the mouth but mesially from both mandibular first molars. The function of this premolar is to assist the mandibular first molar during mastication. Mandibular second premolars have three cusps. There is one large cusp on the buccal side of the tooth.
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When developing the lingual brackets, Craven used reciprocal tip and torque values of that of Lawrence Andrew's straighwire appliance for each tooth in his lingual brackets. Eventually first order bend at the junction of the canine and premolar, and the premolar and molar were placed in the wires as these values were not incorporated in the brackets.
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Rostral hooks can result in improper and extreme molar wear especially to the opposing lower premolar. Other problems include bit problems and soft tissue damage. Fixing Rostral hooks requires that you reduce the dominant portion of the upper premolar and round the unopposed portion smoothly towards the gum. Preventive maintenance is required to prevent recurring Rostral hooks.
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Heterohyrax is a bush hyrax, as opposed to a rock hyrax (Procavia capensis) or a tree hyrax (Dendrohyrax). Although difficult to distinguish in the field, the bush hyrax differs from the rock hyrax in being smaller and less heavily built and having a narrower muzzle. Hyraxes have molariform teeth that are brachydont, meaning they have short crowns and well-developed roots. The bush hyrax has an upper premolar series that is the same length as the molar series, while the rock hyrax has a shorter upper premolar series and the tree hyrax has a longer upper premolar series.
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MACN Pv-RN 975, a fragment of the mandible (lower jaw) preserving one premolar, was discovered in 1991 and tentatively identified as Ferugliotherium by Kielan-Jaworowska and Bonaparte in 1996, but this assignment remains controversial. The poorly preserved and worn premolar is a bladelike tooth, resembling multituberculate fourth lower premolars (p4). The premolar is 4.8 mm long and bears eight faint ridges on both the labial (towards the lips) and lingual (towards the tongue) sides. On the labial side, the four ridges at the back are more widely separated than the four in front of them.
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The lingual cusps (located nearer the tongue) are well developed and functional (which refers to cusps assisting during chewing). Therefore, whereas the mandibular first premolar resembles a small canine, the mandibular second premolar is more alike to the first molar. There are no deciduous (baby) mandibular premolars. Instead, the teeth that precede the permanent mandibular premolars are the deciduous mandibular molars.
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Thus, "biscupid" is technically not as accurate as "premolar". In the universal system of notation, the permanent mandibular premolars are designated by a number. The right permanent mandibular second premolar is known as "29", and the left one is known as "20". In the Palmer notation, a number is used in conjunction with a symbol designating in which quadrant the tooth is found.
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The incisors are long and procumbent and contain a band of enamel on only part of the tooth. The jaw fragment contains a long tooth socket for the incisor and bears a bladelike fourth lower premolar, resembling those of multituberculates. The premolar of Argentodites is similar. Two upper premolars also resemble multituberculate teeth, but whether these premolars are referable to Ferugliotheriidae is controversial.
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Its horseshoe noseleaf helps to focus the ultrasound it uses to 'see'. The greater horseshoe bat also has tooth and bone structures that are distinct from that of other rhinolophids. Its first premolar on the upper jaw protrudes from the row of teeth.Greater horseshoe bat Animal Diversity Web For other horseshoe bats, this premolar is very small or non-existent.
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Where there are two wolf teeth next to each other it is very likely that one is a fragment of the deciduous 2nd premolar.
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Since the lingual cusp is small and nonfunctional, which means it is not active in chewing, the mandibular first premolar resembles a small canine.
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The carnassials are usually formed by the fourth upper premolar and the first lower molar, working one against the other with a scissorlike action.
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The mandibular first premolar is the tooth located laterally from both the mandibular canines of the mouth but mesially from both mandibular second premolars. The function of this premolar is similar to that of canines in regard to tearing being the principal action during mastication. Mandibular first premolars have two cusps. The one large and sharp is located on the buccal side of the tooth.
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Around 10-11 years of age, the primary molars are shed and the permanent premolars erupt in their place. It takes about 3 years for the adult premolar and its root to fully calcify. In the universal system of notation, the permanent maxillary premolars are designated by a number. The right permanent maxillary first premolar is known as "5", and the left one is known as "12".
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When there is excessive height to the lower premolars, the horse has a condition known as ramps. They occur when the upper from the premolar deciduous cap or baby tooth is kept resulting in the abnormal growth of the permanent premolar. The problem with ramps is that they prevent the horse from freely chewing side-to-side. This causes improper and over wear of the molars.
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The next upper premolar (P3) is very small, with a single, pointed cusp that contacts the lingual cingulum (a crest or ridge on the tongue side), which circles the base of the tooth. The two cusps on the last upper premolar (P4) are a large paracone and a smaller protocone. Like other cheirogaleids, their first lower premolar (P2) is caniniform and large, while the cingulids (ridges) on the three lower premolars are more developed compared to most other cheirogaleids. The first two upper molars (M1–2) have a developed hypocone, and the buccal cingulum (a crest or ridge on the cheek side) is well developed on all three upper molars.
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The feature that defines the close association with Hadronomas was the upper first premolar, which was more bulbous with no lingual cingulum, differing it from most Macropods.
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Wołoszyn described the species on the basis of two mandibles, one damaged and with the third premolar (p3) through third molar (m3), and the other intact and with the fourth premolar (p4) through second molar (m2). Miniopterus tao is a large member of the "schreibersii group" and about as large as Miniopterus rummeli from the Miocene of Germany.Ziegler, 2003, p. 487 The mandible is robust and generally resembles M. schreibersii.
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Viewed from the buccal the buccal cusp is centered over the root as in the three cusp variety. Viewed from the mesial or distal its heights of contour are similar to the three cusp variety. Sometimes, premolars are referred to as bicuspids. Even though the terms are synonymous, "bicuspid" refers to having two functional cusps, and the mandibular second premolar is an example of a premolar with three functional cusps.
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The maxillary second premolar is the tooth located laterally from both the maxillary first premolars of the mouth but mesially from both maxillary first molars. The function of this premolar is similar to that of first molars in regard to grinding being the principal action during chewing. There are two cusps on maxillary second premolars, but both of them are less sharp than those of the maxillary first premolars.
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Diagnosis of otodental syndrome was established using clinical, histopathological and audiometric methodologies. In normal individuals, by the age of 2-3, radiograph images should depict any signs of premolar development. A formal diagnosis of no premolar growth can be done by age 6 in order to check for signs of otodental syndrome. Sensorineural hearing loss can be another measure for proper diagnosis as well as checking for ocular coloboma.
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Collar bones are very much reduced, and one incisor, one premolar and three molars are present in each quadrant. The male's penis is directed caudally when not erect.
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Figs, the stones of Parinari excelsa and other large or hard items are often stored in cheek pouches, being cracked open later with the help of strong premolar teeth.
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The wings are dark and the feet are small. Males have a long penis and baculum (penis bone), which is somewhat similar to those of P. endoi, P. abramus and P. paterculus. In the skull, the rostrum (front part) is less flat than in related species and the supraorbital ridges (above the eyes) are prominent. The fourth upper premolar does not touch the upper canine and the second lower premolar is well-developed.
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Dr. Max Pleasure introduced the 'Pleasure curve' where he used a reverse Curve of Monson in the premolar area therefore generating a 'lever' balance effect. This concept arose from observations of tooth wear in both human and primate dentitions. The first molars are flat in the horizontal plane and the second molars follow the Curve of Monson. Similarly, the first premolar teeth are shaped such that they have a reverse curve of Monson.
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This subspecies was named Diceros bicornis longipes by Ludwig Zukowsky in 1949. The word “longipes” is of Latin origin, combining longus (“far, long”) and pēs (“foot”). This refers to the subspecies’ long distal limb segment, one of many special characteristics of the subspecies. Other distinct features of the western black rhino included the square based horn, first mandibular premolar retained in the adults, simple formed crochet of the maxillary premolar, and premolars commonly possessed crista.
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Excavations at Locality 4 in Zhoukoudian, from 1972–73, unearth a Homo sapiens premolar. Modern scientific dating techniques confirm that the site was occupied between 500,000 and 230,000 years ago.
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The forearm length of the holotype was . It had a large nose-leaf of in length and in width. Its first premolar is small and its nasal septum is very thin.
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When compared to other glossophagines, M. redmani is small to medium-sized. The color of its fur is light brown or gray. The species can also be distinguished from other species in the genus by dental characteristics. The diastema between its upper premolars and the first premolar is at least half the length of the first premolar or longer, while other species have a diastema that is less than half the length of their first premolars.
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The mandibular second premolar is the tooth located distally (away from the midline of the face) from both the mandibular first premolars of the mouth but mesial (toward the midline of the face) from both mandibular first molars. The function of this premolar is assist the mandibular first molar during mastication, commonly known as chewing. Mandibular second premolars have three cusps. There is one large cusp on the buccal side (closest to the cheek) of the tooth.
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Teeth are numbered starting at 1 in each group. Thus the human teeth are I1, I2, C1, P3, P4, M1, M2, and M3. (See next paragraph for premolar naming etymology.) In humans, the third molar is known as the wisdom tooth, whether or not it has erupted. Regarding premolars, there is disagreement regarding whether the third type of deciduous tooth is a premolar (the general consensus among mammalogists) or a molar (commonly held among human anatomists).
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With the exception of Prokennalestes, these advanced forms lacked a Meckelian groove. Furthermore, they were equipped with double-rooted canines, a lower premolar with a reduced or absent metaconid and a more elongated lower premolar than their predecessors. In addition, the entoconid and hypoconulid on the lower molars are untwinned, the entotympanic is non-existent, the alisphenoid is enlarged, a Vidian foramen is present as well as a promontorium linked to the paroccipital process via the crista interfenestralis.
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Oligopithecus savagei has a dental formula of 2.1.2.3 on the lower jaw. The canine is relatively small and the front premolar is narrow. It also resembles the callitrichines more than the catarrhines.
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The kinkajou has one less premolar in each row: for a total of 36 teeth. They are mostly solitary animals; mothers generally raise litters of up to four young on their own.
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Hypsiprymnodon moschatus have a fine and delicate skull structure with a rostrum that is narrow and elongate. A long nasal bone structure and distance between the canine and premolar teeth is large.
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Ambondro mahabo is a mammal from the Middle Jurassic (Bathonian) Isalo III Formation (about 167 million years ago) of Madagascar. The only described species of the genus Ambondro, it is known from a fragmentary lower jaw with three teeth, interpreted as the last premolar and the first two molars. The premolar consists of a central cusp with one or two smaller cusps and a cingulum (shelf) on the inner, or lingual, side of the tooth. The molars also have such a lingual cingulum.
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Muroids are most closely related to the Dipodidae, a smaller group of rodents that includes the jerboas, birch mice, and jumping mice.Carleton and Musser, 2005, p. 749 Jerboas have a dental formula of , including incisors in the upper and lower jaws, three molars in the upper and lower jaw, and in most species a small premolar (the fourth upper premolar, P4) in the upper jaw only.Ellerman, 1940, p. 561 In contrast, all muroids lack the P4,Carleton and Musser, 1984, p.
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The posterior premolar teeth are long located between the canines. Their flight patterns are slow with high maneuverability. They have lower wing loading which increases their ability to lift and move quickly and easily.
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The mandibular first premolar is the tooth located laterally (away from the midline of the face) from both the mandibular canines of the mouth but mesial (toward the midline of the face) from both mandibular second premolars. The function of this premolar is similar to that of canines in regard to tearing being the principal action during mastication, commonly known as chewing. Mandibular first premolars have two cusps. The one large and sharp is located on the buccal side (closest to the cheek) of the tooth.
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The maxillary first premolar is the tooth located laterally from both the maxillary canines of the mouth but mesially from both maxillary second premolars. The function of this premolar is similar to that of canines in regard to tearing being the principal action during chewing. There are two cusps on maxillary first premolars, and the buccal cusp is sharp enough to resemble the prehensile teeth found in carnivorous animals. There is a distinctive concavity on the cervical third of the crown extending onto the root.
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Restoration of H. schinzii The genus Halitherium has had a confusing nomenclatural history.D. P. Domning. 1987. Halianassa studeri von Meyer, 1838 (Mammalia, Sirenia): proposed designation of a neotype, and proposed conservation of Halitheirum Kaup, 1838 by designation of a type species. Bulletin of Zoological Nomenclature 44(2):122-125 It was originally coined by Johann Jakob Kaup on the basis of a premolar from the early Oligocene (Rupelian) of southern Germany, but Kaup himself mistakenly stated that the premolar, in his opinion, gehort zu Hippopotamus dubius Cuv.
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Kollikodon is an australosphenidan species, often classified as a monotreme but more recently recovered as an outgroup. It is known only from an opalised dentary fragment, with one premolar and two molars in situ, as well as a referred maxillary fragment containing the last premolar and all four molars. The fossils were found in the Griman Creek Formation at Lightning Ridge, New South Wales, Australia, as was Steropodon. Kollikodon lived in the Late Cretaceous period, during the Cenomanian age (99-96 million years ago).
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Long-eared jerboas have ears that are 1/3 longer than their heads. The incisors are thin and white. A small premolar can be found on each side of the upper jaw. Females have eight mammae.
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It was found in Bolivia by the paleontologist Leonardo Branisa, and it was named after him by Hoffstetter, the scientist who first described and classified it in 1969. Morphologically, it is similar to Proteopithecus, an Oligocene primate from Africa, in its reduced upper second premolar and unreduced lower second premolar. This suggests the primitive platyrrhine ancestors of Branisella came to South America from Africa. Other features, however, suggest that it may have been related to the omomyids, an extinct group of tarsier-like primates found in North America, among other places.
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Miniopterus zapfei is a fossil bat in the genus Miniopterus from the middle Miocene of France. First described in 2002, it is known only from the site of La Grive M, where it occurs with another fossil Miniopterus species, the smaller and more common Miniopterus fossilis. M. zapfei is known from five mandibles (lower jaws) and an isolated fourth upper premolar (P4). The fourth lower premolar is more slender than in M. fossilis and the cingulum shelf surrounding the P4 is less well-developed than in living Miniopterus.
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The dental formula of Ocepeia is , meaning it has 3 incisors, 1 canine, 2 premolars, and 3 molars on each side of the upper and lower jaw. The ancestral eutherian condition is four premolars, and the evolutionary loss of the 1st and 2nd premolar, along with lack of a gap (diastema) between the canine and premolar, is one of the unique distinguishing traits of Ocepeia similar to those of simian primates. The large, stout canine teeth of O. daouiensis are 7.7–8 mm (about .3 in) long and also bear subtle similarities to primate canines.
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The skull is similar to that of dwarf and mouse lemurs, and the auditory bullae are small. Like other cheirogaleids, the dental formula for giant mouse lemurs is ; on each side of the mouth, top and bottom, there are two incisors, one canine, three premolars, and three molars—a total of 36 teeth. Their upper teeth converge towards the front of the mouth, but are straighter than those in mouse lemurs. The first upper premolar (P2) is relatively small, but nearly as tall as the next premolar (P3).
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Partial skull Premolar 1840 illustration As the type genus of Squalodontidae, Squalodon has become a repository for various squalodontids or even taxa that were once thought to belong to Squalodontidae. However, there has been no revision of Squalodon.
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A second, smaller cusp is present in the back crest. The fourth premolar (p4) also has a high central cusp; in addition, there are smaller roots before and behind it on the lingual side. This tooth has two roots.
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In Hungary in 1969, a tooth (the premolar of the Maxilla) was found which dated to the Middle Pleistocene, and was assessed as being midway between that of Canis mosbachensis and Canis lupus spelaeus, but leaning towards C.l. spelaeus.
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An upper premolar is generally variable among the family Sciuridae but is significantly different as seen in A. insularis compared to other Ammospermophilus species. A larger skull is also observed in A. insularis, specifically the zygomatic arches, nasals, and auditory bullae.
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The first upper premolar is absent, the canine is pronounced, and the molars have a longitudinal furrow. As of 1999, it is the longest-lived member of its genus; one individual lived for 31 years and 5 months in captivity.
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Only multirooted teeth have furcation. Therefore, upper first premolar, maxillary and mandibular molars may be involved. Upper premolars have one buccal and one palatal root. Furcation involvement should be checked from the mesial and the distal aspects of the tooth.
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The upper jaw has a high number of incisors, up to ten, and they have more molars than premolars. The second set of teeth grows in only at the 3rd premolar: all remaining teeth are already created as permanent teeth.
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The true machairodontines have a synapomorphy of flattened, small, lower canines and other bone variations such as the small upper first molar compared to basal, pre-saber toothed cats large, transversely situated upper first molar and large upper third premolar parastyle.
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In all known ptolemaiid teeth, there is great wear on the surfaces of premolar 3 to molar 3, in the lower jaw, and premolar 4 to molar 1 in the upper jaw. As the other teeth in the upper jaw were greatly reduced, it is probable that Cleopatrodon and its relatives used these heavy-duty teeth for grinding against one another to crush its food. However, its teeth seemed very unsuited for grinding plant material, as they were not flat. For this reason, it has been hypothesised that it used them for cracking open shells or crushing some other resilient type of food.
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Some features of the teeth differentiate Dermotherium from both living colugo species, but other features are shared with only one of the two. The third lower incisor, lower canine, and third lower premolar at least are pectinate or comblike, bearing longitudinal rows of tines or cusps, an unusual feature of colugos (the first two lower incisors are unknown in Dermotherium). The fourth lower premolar instead resembles the lower molars. The front part of these teeth, the trigonid, is broader in D. chimaera than in D. major, which is known only from the second and third lower molars.
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The maxillary first premolar is one of two teeth located in the upper jaw, laterally (away from the midline of the face) from both the maxillary canines of the mouth but mesial (toward the midline of the face) from both maxillary second premolars. The function of this premolar is similar to that of canines in regard to tearing being the principal action during mastication, commonly known as chewing. There are two cusps on maxillary first premolars, and the buccal (closest to the cheek) cusp is sharp enough to resemble the prehensile teeth found in carnivorous animals. There are no deciduous maxillary premolars.
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The maxillary second premolar is one of two teeth located in the upper jaw, laterally (away from the midline of the face) from both the maxillary first premolars of the mouth but mesial (toward the midline of the face) from both maxillary first molars. The function of this premolar is similar to that of first molars in regard to grinding being the principal action during mastication, commonly known as chewing. There are two cusps on maxillary second premolars, but both of them are less sharp than those of the maxillary first premolars. There are no deciduous (baby) maxillary premolars.
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Buccal Cusp- One other variation of the upper first premolar is the 'Uto-Aztecan' upper premolar. It is a bulge on the buccal cusp that is only found in Native American Indians, with highest frequencies of occurrence in Arizona. The name is not a dental term; it comes from a regional linguistic division of Native American Indian language groups. Buccal-The side of a tooth that is adjacent to (or the direction towards) the inside of the cheek, as opposed to lingual or palatal, which refer to the side of a tooth adjacent to (or the direction towards) the tongue or palate, respectively.
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68-69, Weidenfeld and Nicolson, 1968 The North American C. ossifragus was similar in build to C. lunensis, but had slightly more robust jaws and teeth. It may have preyed on the giant marmot Paenemarmota, and competed with the far more numerous Borophagus diversidens.Wang, Xiaoming & Tedford, Richard H. (2008) Dogs: their fossil relatives and evolutionary history Columbia University Press, A study on the genus' premolar intercuspid notches indicated Chasmaporthetes was likely hypercarnivorous rather than durophagous as its modern cousins (excluding the aardwolf) are.A. Hartstone-Rose (2011) Reconstructing the diets of extinct South African carnivorans from premolar ‘intercuspid notch’ morphology, Journal of Zoology, Vol.
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The skull contains a pronounced swelling around the nose and the second upper premolar is displaced outside the toothrow. The maximum frequency of the echolocation call averages 94.2 kHz and the species can easily be recognized on the basis of its call.
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347 The canine is more robust than in the brown-tailed mongoose. The first upper premolar is small, but the second and third are larger; these two teeth are shorter and broader than in the brown-tailed mongoose.Durbin et al., 2010, p.
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Mathis remarks the exceptional development of the paraconid (or mesiobucal cusp) of the lower P4 premolar. Its premolars and molars were quite small in comparison to the dentition as a whole. The name of the species refers to the Roman settlement of Auderia.
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The mental nerve can be blocked with local anesthesia, a procedure used in surgery of the chin, lower lip and buccal mucosa from midline to the second premolar. In this technique, local anesthetic is infiltrated in the soft tissue surrounding the mental foramen.
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Young bettongs have two molars which are replaced by one adult premolar; this event is a good indication of maturity. The postcranial skeleton of all potoroids has seven cervical, 13 thoracic, six lumbar, two sacral, and 22 caudal vertebrae, with 13 pairs of ribs.
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There is a small diastema between the upper canine and the first premolar (P2), which is smaller and more caniniform than the other premolars. Unlike other lemurs, the first two upper molars (M1 and M2) have prominent lingual cingulae, yet do not have a protostyle.
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The molariform premolar teeth are a characteristic of the genus Leptictidium as a whole which is very marked in the P4 premolars of L. tobieni. The well-developed mesostyle and the transversal configuration of the upper molars are other typical traits of this species.
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Wezmeh Child maxillary right premolar tooth (P3 or possibly P4) of an individual between 6–10 years old from Wezmeh Cave Wezmeh Child or Wezmeh 1 represented by an isolated unerupted human maxillary right premolar tooth (P3 or possibly P4) of an individual between 6–10 years old. It was found with large numbers of animal fossil remains Mashkour, M.; Monchot, H.; Trinkaus, E.; Reyss, J.-L.; Biglari, F.; Bailon, S.; Heydari, S.; Abdi, K. "Carnivores and their prey in the Wezmeh Cave (Kermanshah, Iran): a Late Pleistocene refuge in the Zagros". International Journal of Osteoarchaeology. 19 (6): 678–694. doi:10.1002/oa.997.
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The toothcomb is kept clean by the sublingua or "under-tongue", a specialized structure that acts like a toothbrush to remove hair and other debris. The sublingua extends below the tip of the tongue and is tipped with keratinized, serrated points that rake between the front teeth. Slow lorises have relatively large maxillary canine teeth, their inner (mesial) maxillary incisors are larger than the outer (distal) maxillary incisors, and they have a diastema (gap) between the canine and the first premolar. The first mandibular premolar is elongated, and the last molar has three cusps on the crown, the shortest of which is near the back.
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Besides that, the harmony of the gingival outline between anterior and posterior segments may be affected. Some people are more prone to expose the maxillary teeth from second premolar of one side to another side of second premolar while smiling. Hence, there have been discussions in some cases whereby all teeth between the first molars are included in the procedure, especially in surgical crown lengthening, to achieve an aesthetically pleasing gingival architecture blending in harmoniously the gingival contours of the maxillary anterior and posterior teeth. Apart from that, “black triangles” are likely to develop in areas where there is labial or interproximal soft tissue recession.
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Its skull is long and low with strong occipital and sagittal crests. The canine teeth are exceptionally long, the upper being about three times as long as the basal width of the socket. The first premolar is usually absent. The upper pair of canines measure or longer.
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292 but some species of Pappocricetodon from the Eocene of Asia, one of the earliest known muroids, do have a P4.Emry, 2007, p. 147 Some have suggested that the first molar in muroids is in fact a retained deciduous premolar, but this hypothesis has been discredited.
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Deccanolestes hislopi is based on an isolated first upper molar (VPL/JU/NKIM/10). A third molar, a lower third premolar, various other isolated teeth, and some postcranial remains have been referred to it.Prasad GVR, Sahni A (1988) First Cretaceous mammal from India. Nature 332:638–640.
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Its premolar and molar teeth were quite small in comparison to the dentition as a whole. The name of the species refers to the nose of the animal. The holotype is the complete skeleton of an adult specimen kept in the Forschungsinstitut Senckenberg in Frankfurt am Main.
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The lower third premolar is sectorial. Oligopithecus savagei has primitive molars as compared to other haplorrhines. The lower molars have a trigonid which is higher than the talonid. The lower molars also have a long and obliquely directed cristid obliqua and a small paraconid on the first molar.
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The holotype specimen is deposited at the University of Texas at El Paso Biodiverstiy Collections as UTEP:ES:120-2526. It is an adult, left dentary with the first incisor, fourth premolar and first through third molars. The specimen was collected from Big Manhole Cave in Eddy County, New Mexico.
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Miller’s mastiff bats have a powerfully built body, with a broad body frame and narrow wings. They have a thick mandible in comparison to other mastiff bats. They have a distinctive cusp shaped pattern on their molars and lack their third premolar. Males tend to be larger than females.
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6–7 Cryptonanus usually lacks maxillary fenestrae, perforations of the palate near the first and second molars, has the second upper premolar shorter than the third,Voss et al., 2005, p. 7 lacks a rostral process, which extends the premaxillary bone further to the front,Voss et al.
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On April 30, 1789, the date of his presidential inauguration, although he had mostly dentures, he had only one remaining natural tooth, a premolar. During that same year, he began wearing full dentures. Washington's last tooth was given as a gift and keepsake to his dentist John Greenwood.
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Pappocetus is an extinct protocetid cetacean known from the Eocene of Nigeria and Togo.. Retrieved April 2013. The type specimen BMNH M11414 an incomplete left mandible with symphysis, a deciduous premolar, and unerupted molars. It was found in Bartonian () layers of the Ameki Formation (, paleocoordinates ). Retrieved April 2013.
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A class II skeletal and dental malocclusion was observed in Myrtis' remains. Other reported dental issues are the ectopic labial eruption of the maxillary canines mesially to their retained deciduous predecessors, the ectopic distally directed eruption of a lower first premolar and a unilaterally missing lower third molar.
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Hans Thewissen with the holotype Ambulocetus skeleton The first remains were unearthed by an expedition jointly funded by Howard University and the Geological Survey of Pakistan, in the upper Kuldana Formation in the Kala Chitta Hills of Punjab, Pakistan, dating to the middle Eocene. The formation is constrained to sometime during the Lutetian stage. The holotype specimen, HGSP 18507, is a partial skeleton initially discovered preserving a partial skull excluding the snout, some elements of the vertebral column and ribs, as well as portions of the fore- and hind-limb. Other specimens initially found were HGSP 18473 (a second premolar), HGSP 18497 (a third premolar), HGSP 18472 (a tail vertebra), and HGSP 18476 (lower portion of a femur).
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Australopithecines are generally considered to have had a faster, apelike growth rate than modern humans largely due to dental development trends. Broadly speaking, the emergence of the first permanent molar in early hominins has been variously estimated anywhere from 2.5–4.5 years of age, which all contrast markedly with the modern human average of 5.8 years. The tips of the mesial cusps of the 1st molar (on the side closest to the premolar) of KNM-ER 1820 were at about the same level as the cervix (where the enamel meets the cementum) of its non-permanent 2nd premolar. In baboons, this stage occurs when the 1st molar is about to erupt from the gums.
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Surameryx is known from the left half of the nearly complete lower jaw, reminiscent of the North American palaeomerycids, which are known from numerous fossils. The jaw of Surameryx is similar to that of Barbouromeryx in having a premolar row without reduction compared to the molar row; additionally it showed the characteristic "Palaeomeryx fold", a typical molar crest present in various types of primitive ruminants, and a vertical groove on the back or inner surface of the fourth premolar. Surameryx still differs from its relatives in the much wider shape of the molars and premolars, and in its shorter, upward recurved coronoid process; the stylids were also higher than in other related genera.
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The morphology of the premolar deduced from the impression at the palate was proposed to separate the sister taxon as separate and previously unknown genus. The holotype material is composed of the partial remains of the left maxillary, still set with the direct evidence of the second and third molar (M2–M3), roots for third premolar (P3) to M1, the impression of the alveoli at M4, and the root at the arch of the cheek. A partial right maxillary is also described, preserved inset with P3–M2 and revealing the alveoli for M1 and P1–2. Another specimen, the left M3, was included as a paratype for the original description of Microleo attenboroughi.
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Its skull has a rostral projection; the projection is on the top of the skull, with its leading edge aligned over the fourth premolar. Its head and body is long. Its tail is ; its ears are . It has a very narrow connecting process between the sella and the posterior lancet.
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Descending upon the tuberosity of the maxilla, it divides into numerous branches, it descends on the posterior surface of the maxilla and gives branches that supply the molar and premolar teeth and the lining of the maxillary sinus, while others are continued forward on the alveolar process to supply the gingiva.
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Odontogenic infections may spread to involve the canine space. The most likely causative tooth is the maxillary canine or maxillary first premolar. This occurs when pus (e.g. from a periapical abscess), perforates the buccal cortical plate of the maxilla above the level of attachment of the levator anguli oris muscle.
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A fragment of the lower jaw shows that the tooth socket of the lower incisor was very long, extending below the fourth premolar (p4). The p4 is preserved in this fragment. It is blade-shaped and resembles multituberculate p4s. However, the determination of this fossil as Ferugliotherium is in question.
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It descends with the inferior alveolar nerve to the mandibular foramen on the medial surface of the ramus of the mandible. It runs along the mandibular canal in the substance of the bone, accompanied by the nerve, and opposite the first premolar tooth divides into two branches, incisor and mental.
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Archäologische Mitteilungen aus Iran und Turan.34, 171-194. Location map of the Wezmeh Cave in the range of Neanderthals The premolar is relatively large compared with both Holocene and Late Pleistocene P3 and P4.Trinkaus, E.; Biglari, F.; Mashkour, M.; Monchot, H.; Reyss, J. L.; Rougier, H.; Heydari, S.; Abdi, K. (2008).
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There is fur lining the inner ears, which are almost invisible. Black-spotted cuscuses can be distinguished from other cuscuses by their teeth. They have low crowns and small premolars that lie anterior to the primary premolar in the upper jaw. In addition, they have a prominent protocone on their first, upper molars.
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The enamel of the lower premolars is crenulated (has scalloped edges). The fourth premolar is a high triangular shape. Like other ancient cetaceans, and most pronouncely in ambulocetids, the lower molars are shorter than the back premolars. The lower premolars are larger than those of Pakicetus and are separated by wider gaps (diastema).
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Raemeotherium is an extinct genus of diprotodont marsupial from the late Oligocene Namba Formation of South Australia. It was much smaller than other diprotodonts, approximately the size of a lamb, and comparatively gracile. It is usually placed within the Zygomaturinae, but because the upper third premolar is unknown doubt remains about its affinities.
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Tabelia hammadae, which was also considered to be one of the oldest known simians along with Algeripithecus, was shown to be a synonym of Azibius when more complete fossils were discovered at Gour Lazib between 2003 and 2009. Likewise, the second upper molar (M2) of Dralestes hammadaensis have been reinterpreted as being the upper fourth premolar (P4) of Azibius and has been considered a synonym. However, in 2010, Godinot cautiously suggested that Dralestes may be a synonym of Algeripithecus based on a blade-like premolar. He also reasserted his view that Algeripithecus was a simian based on its upper molar morphology and hypothesized that this applied to all azibiids, favoring his earlier view that they may be early simians instead of stem lemuriforms.
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The known material (hypodigm) of Miniopterus zapfei includes a mandible (lower jaw) with the fourth premolar (p4), first molar (m1), and second molar (m2); a mandible with m1; a mandible with m1 and m2; a mandible with m2 and the third molar (m3); a mandible without any teeth; and an isolated fourth upper premolar (P4). Some of the mandibles also preserve the alveoli (openings) for teeth that have not been preserved. The dimensions of the p4 (length and width) are 1.03 x 0.88 mm; m1 is 1.57 to 1.60 x 1.01 to 1.07 mm; m2 is 1.51 to 1.64 x 0.95 to 1.05 mm; the single m3 is 1.41 mm long; and the single P4 is 1.38 x 1.52 mm.Mein and Ginsburg, 2002, pp.
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In this bilateral balanced occlusal scheme, the posterior teeth are set up at different angles in the coronal plane; 5° for the first premolar teeth, 10° for second premolar teeth, and 15° angle for both the first and second molar teeth. In addition, the occlusal surfaces of mandibular posterior teeth are reduced in a buccal lingual dimension with the aim of improving stability of, particularly the lower prosthesis. Regardless which of the above occlusal schemes are adopted, it is difficult to achieve bilateral balanced occlusion in the prosthetic laboratory. Notwithstanding this, this aspiration of bilateral balanced occlusion is easier to achieve if the 'Buccal Upper Lingual Lower (BU-LL) and Mesial Upper -Distal Lower (MU-DL)' rules are adopted for adjusting cusps.
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Excavation work was recommenced in 1949 unearthing new Peking Man fossils including 5 teeth and fragments of thigh and shin bone. The following year a third premolar was discovered in the material sent back to Uppsala by Zdansky in 1921 and 1923. The Peking Man Site is designated type section of cave deposits of Middle Pleistocene in North China by the Annual Congress of the National Committee of Stratigraphy of China 1959 and a mandible fragment is unearthed. Excavations led by Pei in 1966 unearthed a premolar and two pieces of skull fragment, these were discovered to match fragments retained from previous excavations in 1934 and 1936, and the only extant example of a nearly complete skullcap was pieced together.
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Kielan-Jaworowska, Zofia, Richard L. Cifelli, and Zhe-Xi Luo (2005). Mammals from the Age of Dinosaurs: Origins, Evolution, and Structure , p. 299 Multituberculates are notable for the presence of a massive fourth lower premolar, the plagiaulacoid; other mammals, like Plesiadapiformes and diprotodontian marsupials, also have similar premolars in both upper and lower jaws, but in multituberculates this tooth is massive and the upper premolars aren't modified this way. In basal multituberculates all three lower premolars were plagiaulacoids, increasing in size posteriorly, but in Cimolodonta only the fourth lower premolar remained, with the third one remaining only as a vestigial peg-like tooth, and in several taxa like gondwanatherians and taeniolabidoideans, the plagiaulacoid disappeared entirely or was reconverted into a molariform tooth.
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The second premolar is also placed right up against the first molar rather than noticeably separated from it. The bat has a nose leaf, elongated muzzle, and a papillated tongue. The tongue is used to gather pollen from flowers. The bat can elongate individual papillae to create a "mop" that can lap up pollen.
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Argentodites is known from a single premolar tooth, MPEF 604, in the collections of the Museo Paleontológico "Egidio Feruglio" in Trelew, Argentina.Kielan-Jaworowska et al., 2007, pp. 257–258. It is from the middle part of the La Colonia Formation of Chubut Province, Argentina, which is Late Cretaceous (Maastrichtian and perhaps partly Campanian) in age.
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Jaw fragment of Ambondro mahabo seen from the inner (lingual) side. Scale bar is 1 mm. Ambondro mahabo was described from the middle Jurassic (Bathonian, about 167 million years ago) of northwestern Madagascar in 1999. It is known from a single lower jaw fragment with three teeth, probably the last premolar and first two molars.
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The premolars, also called premolar teeth, or bicuspids, are transitional teeth located between the canine and molar teeth. In humans, there are two premolars per quadrant in the permanent set of teeth, making eight premolars total in the mouth. They have at least two cusps. Premolars can be considered transitional teeth during chewing, or mastication.
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Cats have highly specialized teeth for killing prey and tearing meat. The premolar and first molar, together called the carnassial pair, are located on each side of the mouth. These teeth efficiently function to shear meat like a pair of scissors. While this feature is present in canids, it is highly developed in felines.
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"Hence most of the prosimians and platyrrhines have three premolars. Some genera have also lost more than one. A second premolar has been lost in all catarrhines. The remaining permanent premolars are then properly identified as P2, P3 and P4 or P3 and P4; however, traditional dentistry refers to them as P1 and P2".
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It was described in 2013. Its closest relative is the dark-brown serotine, Neoromicia brunnea. Rosevear's serotine and the dark-brown serotine are separated by a genetic distance of 6.9-7.2%. The new species was assigned to the genus Neoromicia based on its single upper premolar: a trait shared amongst all species in the genus.
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Tissue supported expanders allow the forces to be applied directly to the tissues of palatal mucosa instead of teeth. The most common type of tissue-borne expander is known as the Haas Appliance. This appliance was popularized by Andrew Haas in 1961. This appliance involves bands placed on maxillary first premolar and first molars on each side.
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Other features which it shares with other specialised gum-eating primates, such as the Masoala fork-marked lemur, include a long, extensible tongue, an enlarged upper first premolar, a large caecum and sharp nails for climbing and gripping. A solitary, nocturnal animal, the southern needle- clawed bushbaby communicates with other individuals by voice and by urine marking.
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Since the lingual cusp (located nearer the tongue) is small and nonfunctional (which refers to a cusp not active in chewing), the mandibular first premolar resembles a small canine. There are no deciduous (baby) mandibular premolars. Instead, the teeth that precede the permanent mandibular premolars are the deciduous mandibular molars. Sometimes, premolars are referred to as bicuspids.
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The Zhangheotheriidae and Spalacotheriidae families form the superfamily Spalacotheroidea. Akidolestes cifellii has acute triangulation of the molar cusp pattern, which is characteristic of Spalacotheroids. However, unlike to Maotherium, which has symmetrical premolar and molar patterns, Akidolestess premolars and molars are gradually longer, respectively. Also, Akidolestes has protocristid on its molars, which is different from Zhangheotherium and Maotherium.
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Triangular ridges are those that project from the cusp tips of premolar and molars to the central groove. Transverse ridges are formed by the union of two triangular ridges on posterior teeth. The joining of buccal and lingual triangular ridges is usually named as an example. The oblique ridge is found on the occlusal surfaces of maxillary molars.
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It is most commonly seen in the canine and premolar regions of the mandible, and are sometimes confused with lateral periodontal cysts. It is not normally problematic, but when it grows larger, it can cause some discomfort. It can be removed by simple surgical excision. They are developed late in life, generally up to the sixth decade of age.
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In 1754, another French dentist, Louis Bourdet, dentist to the King of France, followed Fauchard's book with The Dentist's Art, which also dedicated a chapter to tooth alignment and application. He perfected the "Bandeau" and was the first dentist on record to recommend extraction of the premolar teeth to alleviate crowding and to improve jaw growth.
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In such a case LLA prevents the permanent molars from migrating mesially (forward) thus blocking off the eruption space for the premolar teeth. LLA is also used in order to maintain the so-called "Leeway space", which is the extra space available in the arch when the deciduous molars are exfoliated and replaced by smaller permanent premolars.
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Its teeth were small relative to body size. The lack of a diastema (gap) between the second incisor and first premolar of the mandible indicates that Oreopithecus had canines of size comparable to the rest of its dentition. In many primates, small canines correlate with reduced inter-male competition for access to mates and less sexual dimorphism.
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There is thus some discrepancy between nomenclature in zoology and in dentistry. This is because the terms of human dentistry, which have generally prevailed over time, have not included mammalian dental evolutionary theory. There were originally four premolars in each quadrant of early mammalian jaws. However, all living primates have lost at least the first premolar.
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The fossil record of Carpodaptes is relatively sparse excluding jaw and teeth fragments. However, much can be concluded off of these few fragments. Their upper jaw had a dental formula of 2:1:3:3 and 2:1:2:3 on their lower jaw. Carpodaptes are characterized by their plagiaulacoid dentition seen on their first lower premolar.
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An OAC is an abnormal physical communication between the maxillary sinus and the mouth. This opening is only present when the structures, that normally separates the mouth and sinus into 2 separate compartments, are lost. There are many causes of an OAC. The most common reason is following extraction of a posterior maxillary (upper) premolar or molar tooth.
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A further clue suggesting these might be Goodsir's remains was a gold filling in a premolar tooth, unusual at that time. Goodsir's family were friendly with Robert Nasmyth, an Edinburgh dentist with an international reputation for such work. Harry's brother John had served as dental apprentice to Nasmyth.Lindsay L. Medical Polemics from Hunter to Owen, 1772-1844.
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Hipposideros besaoka is known from numerous jaw bones and isolated teeth.Samonds, 2007, pp. 49, 51 The material is identifiable as Hipposideros by the dental formula of (one incisor, one canine, two premolars, and three molars in the upper dentition on both the left and right; two incisors, one canine, two premolars, and three molars in the lower dentition on the left and right); the second upper premolar (P2) is shifted out of the toothrow toward the side of the skull, so that the canine (C1) and P4 touch or nearly touch; and the second lower premolar (p2) is large and has a broad, steep facet on the buccal (outer) side. Morphometric analysis shows that H. besaoka is significantly different from H. commersoni and falls outside the substantial variation within that species.
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Case's premise later inspired Charles Tweed in the 1940s to promote premolar extraction and extraction as the ideal way to prepare a patient for orthodontic treatment: 4 healthy adult premolars are extracted and the rest of the teeth are pulled back with rubber bands. Premolar extraction rose to popularity in the 1970s, when up to 60% percent of all patients were routinely treated with the Tweed technique. At the same time, it was observed in research published in the AJO-DO that this technique led to the retrusion of the jaws, "flattened" profile, and reduced vertical dimension. The controversy about extraction reached its peak in 1986 when a young woman sued her orthodontist for the "mutilation" of her face due to the extraction treatment, and the severe jaw pained it caused (cf Susan Brimm case).
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A restored premolar After a tooth has been damaged or destroyed, restoration of the missing structure can be achieved with a variety of treatments. Restorations may be created from a variety of materials, including glass ionomer, amalgam, gold, porcelain, and composite."Oral Health Topics: Dental Filling Options". ada.org. Small restorations placed inside a tooth are referred to as "intracoronal restorations".
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The coat is light olive white in the under parts and buffy umber brown in the upper parts. The standard adult mass is 16.5 grams. This species has one premolar in each side of the upper jaw. There is slight sexual dimorphism between males and females, with female body size moderately smaller than males but male cranial size is slightly smaller than females.
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Kielan- Jaworowska et al., 2007, p. 258. The premolar was described in 2007 by Zofia Kielan-Jaworowska and colleagues as a new genus and species, Argentodites coloniensis. The generic name, Argentodites, combines "Argentina" with the Ancient Greek hodites "traveler", in reference to the animal's presumed migration from North America to Argentina, and the specific name, coloniensis, refers to the La Colonia Formation.
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In addition, Cope mistakenly classified the Ptilodus genus as a marsupial. He originally named it Chirox, and placed it in the new family Chirogidae in 1887. Since it has been reclassified, and Chirogidae is now officially a synonym of Ptilodontidae. One of the most outstanding features of this family of squirrel-like, arboreal mammals, was the peculiar shape of their last lower premolar.
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More derived (specialized) species have larger teeth and longer, more slender nasal bones (also producing a larger incision). The various species also differ in the depth of the nasal incision: in A. megalodus, it reaches the front of the fourth premolar; in A. malacorhinus, it reaches the rear of that tooth; and in A. mutilus, it reaches the first molar.
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The fourth lower premolar is submolariform. A metaconid is lacking, although on some teeth slight thickenings of the enamel are present in this region. Talonid cusps are slightly differentiated. The first and second lower molars are approximately the same length (M1, average length x=- 1.93 mm, N- 13; M2, x=2.00 mm, N- 9); M. is longer (x= 2.32 mm, N -7).
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The upper canine is a little larger than the upper incisors, and, like them, directed slightly buccally and mesially. P1, only preserved in a single specimen, is the only single-rooted upper premolar. Apparently, P1 is conical, smaller than the remaining premolars and lacks accessory denticles. P2 is the largest upper tooth and the first in the upper row with large accessory denticles.
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It was a cougar-sized animal and may have had habits similar to those of a cougar. Its body had the same shape as a cougar except for a long and compressed upper canine. This would place this cat into the "false-sabertooth" group. Apart from that Adelphailurus had a retained upper second premolar, which is unusual for a cat.
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Typical features of this genus are a bulging forehead and powerful jaws; it was probably a scavenger. Its crushing premolar teeth and strong jaw muscles would have been used to crack open bone, much like the hyena of the Old World. The adult animal is estimated to have been about in length, similar to a coyote, although it was much more powerfully built.
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Typical features of this genus are a bulging forehead and powerful jaws; it was probably a scavenger. Its crushing premolar teeth and strong jaw muscles would have been used to crack open bone, much like the hyena of the Old World. The adult animal is estimated to have been about in length, similar to a coyote, although it was much more powerfully built.
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Typical features of this genus are a bulging forehead and powerful jaws; it was probably a scavenger. Its crushing premolar teeth and strong jaw muscles would have been used to crack open bone, much like the hyena of the Old World. The adult animal is estimated to have been about in length, similar to a coyote, although it was much more powerfully built.
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For this tooth, the left and right second premolars would have the same number, "5", but the right one would have the symbol, "┘", underneath it, while the left one would have, "└". The international notation has a different numbering system than the previous two, and the right permanent maxillary second premolar is known as "15", and the left one is known as "25".
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Weight ranges 12-19 lbs. In Sri Lanka, they can attain slightly greater sizes than their mainland cousins. Jackals in Sri Lanka, though classed as the same subspecies as those in southern India, have a rooted lobe on the inner side of the third upper premolar. The winter coat of Sri Lankan jackals is shorter, smoother and not as shaggy than those of northern Indian jackals.
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The side-striped jackal's skull is similar to that of the black- backed jackal's, but is flatter, with a longer and narrower rostrum. Its sagittal crest and zygomatic arches are also lighter in build. Due to its longer rostrum, its third upper premolar lies almost in line with the others, rather than at an angle. Its dentition is well suited to an omnivorous diet.
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Advanced tooth decay on a premolar Dental caries (cavities), described as "tooth decay", is an infectious disease which damages the structures of teeth.Dental Cavities, MedlinePlus Medical Encyclopedia. The disease can lead to pain, tooth loss, and infection. Dental caries has a long history, with evidence showing the disease was present in the Bronze, Iron, and Middle ages but also prior to the neolithic period.
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Anatomy: The mandibular second premolar most commonly has three cusps but can have two as well. The three cusp variety has one large cusp on the buccal with two smaller lingual cusps. The mesiolingual cusp is twice the size of the distolingual cusp. Viewed from the occlusal (looking down onto the biting surface of the tooth) the tooth is rather square in outline, particularly on the lingual.
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Different kit fox families can occupy the same hunting grounds, but do not generally go hunting at the same time. The Kit Fox experiences a very interesting, but rare, tooth malformation that causes Bigeminy: a heart rhythm problem. This is caused by the fusion of a maxillary third premolar tooth and an adjoining supernumerary tooth which makes a single tooth with two cusps and three roots.
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In carnivorans the carnassial pair is made up by the fourth upper premolar and the first lower molar teeth. There is variation among the carnassial pair depending on the family. Some species are cursorial and the foot posture in terrestrial species is either digitigrade or plantigrade. In pinnipeds the feet have become flippers where the locomotion is unique in each of the pinniped families.
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Including malocclusion of the dental arches (the maxilla and mandible), radiological findings in some cases have indicated significant overgrowth of the mandibular premolar and molar roots; hypercementosis (overproduction of cementum) of the molars and maxillary incisors; enlarged, funnel-shaped mandibular lingula (spiny structures on the ramus of the mandible); and a radiolucent effect on portions of many teeth, increasing their transparency to x-rays.
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The fourth upper premolar (P4) has four main, transversely placed crests;De Bruijn, 1998, p. 112; Prieto and Böhme, 2007, p. 303 the description of S. bolligeri mentions an additional, centrally placed small crest. De Bruijn interpreted the four main crests as the anteroloph, protoloph, metaloph, and posteroloph from front to back and wrote that these crests are not connected on the sides of the tooth.
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Myocastorini members share long upper incisor roots (except Callistomys), and mid- to long-sized lower incisor roots. These five genera share either four (Callistomys, Thrichomys) or five (Hoplomys, Myocastor, Proechimys) lophids on the lower deciduous fourth premolar, three roots anchoring the upper molars, and well-connected lophs on cheek teeth. Members display a variety of lifestyles including terrestrial (Hoplomys, Proechimys, Thrichomys), arboreal (Callistomys), and amphibious (Myocastor) adaptations.
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Typical features of this genus are a bulging forehead and powerful jaws; it was probably a scavenger. Its crushing premolar teeth and strong jaw muscles would have been used to crack open bone, much like the hyena of the Old World. The adult animal is estimated to have been about 80 cm in length, similar to a coyote, although it was much more powerfully built.
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Typical features of this genus are a bulging forehead and powerful jaws; it was probably a scavenger. Its crushing premolar teeth and strong jaw muscles would have been used to crack open bone, much like the hyena of the Old World. The adult animal is estimated to have been about 80 cm in length, similar to a coyote, although it was much more powerfully built.
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Typical features of this genus are a bulging forehead and powerful jaws; it was probably a scavenger. Its crushing premolar teeth and strong jaw muscles would have been used to crack open bone, much like the hyena of the Old World. The adult animal is estimated to have been about 80 cm in length, similar to a coyote, although it was much more powerfully built.
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Typical features of this genus are a bulging forehead and powerful jaws; it was probably a scavenger. Its crushing premolar teeth and strong jaw muscles would have been used to crack open bone, much like the hyena of the Old World. The adult animal is estimated to have been about 80 cm in length, similar to a coyote, although it was much more powerfully built.
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Discovered in 1927 this north-south running fissure is filled with yellow sandy clay and dates to the late Middle Pleistocene era. Excavations from 1937–38 unearthed stoneware, burned bones and seeds (indicating fire use in early man) and fossils of jackal and deer. A second excavation in 1973 unearthed a human premolar and the fossilised remains of 40 mammalian species including macaque, pig, bear and horse.
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There was a diastema (gap) between the incisors and molars of the mandible. The lower incisors were broad, recurved, and placed in a straight line across. The p3 premolar tooth of the mandible was present in most early specimens, but lost in later specimens; it was only present in 6% of the La Brea sample. There is some dispute over whether Smilodon was sexually dimorphic.
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Mountain beavers have an unusual projection on each molar and premolar tooth, which is unique among mammals and allows for easy identification of teeth. This projection points toward the cheek on the upper tooth row, but points toward the tongue on the lower. The cheek teeth lack the complex folds of other rodents and instead consist of single basins. They are hypsodont and ever-growing.
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Dentition of the species resembles that of the extant potoroids, but for that family's incisor formula of I3/1. The dental formula of H. moschatus is I3/2 C1/0 PM1/1 M4/4. Two premolars found in juveniles are replaced at maturity when a single sectorial premolar erupts. The sequence of emerging molars and premolars allows the age of the individual to be determined.
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The Diatomyidae are similar to both the Ctenodactylidae and the Anomaluromorpha in being simultaneously hystricomorphous and sciurognathous. The masseteric fossa in diatomyids is enlarged and extends to below the first cheek tooth. The enamel on incisors is multiserial (similar to the springhare, gundis, and Hystricognathi). The single premolar on both the upper and lower tooth rows is enlarged (unlike the reduced state in Ctenodactylidae).
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Nakali has also yielded a black rhino specimen, the pig Nyanzachoerus, an antelope, the hippo Kenyapotamus, the rhino Kenyatherium, the giraffe Palaeotragus, the horse Hipparion, the elephants Deinotherium and (possibly) Choerolophodon, and the colobine monkey Microcolobus. The third premolar of a small nyanzapithecine ape was also found in Nakali, and Samburupithecus was nearly contemporaneous with Nakalipithecus, and was discovered to the north of Nakali.
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Skull of the cimolodontan multituberculate Ptilodus, showing the large fourth lower premolar (in the lower jaw, behind the incisor) The single known example of Argentodites is a blade-like fourth lower premolar (p4). It has a length of 4.15 mm, height of 2.10 mm, and width of 1.35 mm. The crown is nearly complete, but the roots are largely missing. Kielan-Jaworowska considered two possible orientations of the tooth—one with the back margin nearly vertically, and the other with the margin inclined backward—but preferred the former, which made for more natural placement of the roots. Although the left and right sides of the tooth are almost identical, they believed the tooth is most likely a left p4, as this would make the lingual (inner) side the more convex one, as is usual in the p4 of cimolodontan multituberculates with a large p4.
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Ammospermophilus insularis diverged from Ammospermophilus leucurus species (specific to southern Baja California peninsula) and display similar characteristics. Both species contain two defined black bands alternating with three white bands on the underside of the tail. There are, however, several unique traits that distinguish A. insularis from A. leucurus. A. insularis males and females are slightly larger and darker compared to A. leucurus and display missing or vestigial upper premolar.
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The entirety of the under belly, inner side of the limbs, and lining of the pouch are pure white. Dentition shows two premolar teeth in both the upper and lower jaws, with the first observed as smaller than the second in the upper jaw. The most obvious feature that distinguishes D. blythi from D. cristicauda is the sandy colour and the lack of a crest on the tail.
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M. macpheei lacks an extension of the protocone cusp on the lingual (inner) side of the third upper premolar (P3) and P4, present in M. brevicaudata, and has the paracone cusp on P4 less well-developed. On the other hand, the front part of the ectostyle crest on P4 is larger. The relative lengths of some of the crests on the two last molars also differ between the two species.
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The presence of buccal exostosis can be diagnosed by both clinical examination and radiological interpretation of the oral cavity. Clinically, buccal exostoses appear as single, broad-based masses, usually situated bilaterally in the premolar and molar region on the facial surface of the maxillary alveolar bone. The mass is generally smooth although in some cases a sharp, bony prominence may be present resulting in tenderness beneath the mucosa.Bouquot JE. 4th ed.
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P 1982 "Middle Miocene Kangaroos (Macropoidea:Marsupialia) from three localities in Northern Australia, with a description of two new subfamilies". Journal of Geology and Geophysics, 7, 287-302. Primitive macropodines have the straight molar row in common. Ekaltadeta also has plesiomorphic features in that the dental canal and masseteric canal are separated anteriorly, below premolar three and the first molar, with the masseteric canal terminating in a cul-de-sac.
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The fourth lower premolar (p4) is known from a poorly preserved specimen from Oberdorf and a less worn specimen from Tägernaustrasse. There are four ridges, of which the front and back pair are connected at the lingual side and in the Oberdorf specimen also at the labial side. This tooth is similar to that of Muscardinus hispanicus, but the front pair is better developed. There is one root.
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High Translucent zirconium fixed - fixed bridge built with VM9 vita porcelain and stained with luster paste. The upper first premolar is considered the pontic and the teeth prepared are abutments. Conventional bridges are bridges that are supported by full coverage crowns, three-quarter crowns, post-retained crowns, onlays and inlays on the abutment teeth. In these types of bridges, the abutment teeth require preparation and reduction to support the prosthesis.
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The fisher and the genus Martes were determined to have descended from a common ancestor, but the fisher was distinct enough to put it in its own genus. It was decided to create the genus Pekania and reclassify the fisher as Pekania pennanti. Members of the genus Pekania are distinguished by their four premolar teeth on the upper and lower jaws. Its close relative Mustela has just three.
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Lemuriforms groom orally, and also possess a grooming claw on the second toe of each foot for scratching in areas that are inaccessible to the mouth and tongue. It is unclear whether adapiforms possessed grooming claws. The toothcomb consists of either two or four procumbent lower incisors and procumbent lower canine teeth followed by a canine-shaped premolar. It is used to comb the fur during oral grooming.
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349 The fourth premolar is large, as is the first molar. The second upper molar is less than one-third the size of the first, and is more highly reduced than that of the brown-tailed mongoose, which is about two-thirds the size of the first molar. The first lower incisor is smaller than the other two. The lower canine, premolars, and first molar are well-developed.
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Instead, the teeth that precede the permanent maxillary premolars are the deciduous maxillary molars. In the universal system of notation, the permanent maxillary premolars are designated by a number. The right permanent maxillary second premolar is known as "4", and the left one is known as "13". In the Palmer notation, a number is used in conjunction with a symbol designating in which quadrant the tooth is found.
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There are two rows of cusps, and each lingual cusp is connected to each labial cusp by a broad crest, with one or more fossas in the middle. One of the two labial cusps may have been divided into two smaller cusps. The two crests are separated by a deep furrow. The enamel prisms of this tooth are small, like those of the premolar MACN Pv-RN 250.
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The most frequent locations of a mandibular fracture. This is the most useful classification, because both the signs and symptoms, and also the treatment are dependent upon the location of the fracture. The mandible is usually divided into the following zones for the purpose of describing the location of a fracture (see diagram): condylar, coronoid process, ramus, angle of mandible, body (molar and premolar areas), parasymphysis and symphysis.
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Dentition Mesocarnivore cheek teeth are heterodont and their different shapes reflect distinct functions. Incisors and canines are used to apprehend food and kill prey, pointed premolars pierce and hold prey, and molars are involved in both slicing and crushing functions. The slicing function of the molars is produced by occlusion between the carnassials, the lower first molar, and the upper fourth premolar. Mesocarnivores are first represented by the Miacidae.
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Also according to Yahnke (1995; et al.1996) the present restricted range is a relic of a much wider former range. Zoologists noted the distinctiveness in the ecological niche, appearance, and behavior of this species. Darwin's fox is differentiated from the gray fox in being darker; having shorter legs; a broader, shorter skull; smaller auditory bullae; a more robust dentition; and a different jaw shape and style of premolar occlusion.
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This is unusual in wallabies and other macropods, which typically prefer grazing. Tooth structure reflects this preference for browsing, with the shape of the molars differing from other wallabies. The fourth premolar is retained through life, and is shaped for cutting through coarse plant material. There is evidence that the swamp wallaby is an opportunist taking advantage of food sources when they become available, such as fungi, bark and algae.
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The infraorbital canal is enlarged, presumably allowing for the passage of the medial masseter muscle as with other hystricomorphs. The mandible is sciurognathous. As with other diatomyids, Diatomys has no coronoid process and the masseteric fossa extends far forward to below the fourth premolar. The postcranial skeleton does not appear to have any unique specializations that might be associated with a fossorial, arboreal, or saltatorial way of life.
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The evidence for post-canine megadontia comes from measuring post-canine tooth surface area of hominid specimens and comparing these measurements to other hominid species. Australopithecus, dated to have lived 2 to 3 million years ago, is the earliest hominid genus to demonstrate post-canine enlargement, with average post-canine tooth area ranging from approximately 460mm2 and going all the way up to the largest tooth area, 756mm2, which is seen in Paranthropus boisei . After Australopithecus, a trend of steady decline in post-canine size is observed, starting in the genus Homo and culminating with Homo sapiens which has an average post-canine tooth area of only 334mm2. Studies of premolar size in hominid species that predate Australopithecus afarensis show long, uni-cuspid teeth at the P3 location, while species dated after A. afarensis have been shown to have wider, bicuspid teeth at the same location, which is hypothesized to show the beginnings of canine to premolar evolution in hominids.
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Horns In 1997, an almost complete skull of O. rothii proved that it was similar to Samotragus praecursor, with a short face, compared to its relatively long braincase, and isolated horn cores. However, unlike S. praecursor, O. rothii had a jaw of primarily premolar teeth, which were longer than the molars found in the latter. Pilgrim and Hopwood described the genus as being "small size with long slender muzzle; face bent down on basicranial axis either slightly or to a moderate extent; orbits with expanded orbital roof; horn-cores twisted counter-clockwise in a fairly close spiral of one or two revolutions, widely separate, tilted backward or fairly upright, divergent, with a cross-section almost circular or elliptical, keeled either anteriorly or posteriorly or both; dentition moderately hypsodont, premolar series rather long and slender, molars broad with ribs of medium strength" (Pilgrim and Hopwood, 1928, p. 24). The horn cores of Oioceros have a torsion.
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A later excavation in 1959 revealed no new hominins, and Laetoli went relatively unexplored until 1974—when the discovery of a hominin premolar by George Dove revived interest in the site. Mary Leakey returned and almost immediately discovered the well-preserved remains of hominins. In 1978, Leakey's 1976 discovery of hominin tracks—"The Laetoli Footprints"—provided convincing evidence of bipedalism in Pliocene hominins and gained significant recognition by both scientists and laymen.
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The dental formula is for a total of 28 teeth; very occasionally, individuals have been found with an additional upper premolar on each side of the mouth, for a total of 30 teeth. The skull is larger and more robust than any other megabat in Africa, with a pronounced, massive snout. The tongue is large and powerful, with an expanded, tridentate tip. The tongue has backwards-facing papillae used to extract juice from fruits.
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Neohelos is an extinct diprotodontid marsupial, that lived from the early to middle-Miocene. There are four species assigned to this genus, Neohelos tirarensis, the type species, N. stirtoni, N. solus and N. davidridei. N. davidridei is the most derived species of the genus, and its premolar morphology shows that it is structurally and ancestor of the genus Kolopsis. All four species are from the Bullock Creek in the Northern Territory and Riversleigh of Australia.
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It had a sharply limited band of enamel, and grew continually. The p3 premolar was very small, and adhered entirely to the lower diastema under the larger p4. The blade-like p4 was roughly trapezoidal in side view, and had three cusps along the horizontal upper margin and one cusp on the outer back side. The p4 did not have the ridges on the outer and inner side, as are present in other multituberculates.
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The Kents Cavern 4 maxilla is a human fossil, consisting of a right canine, third premolar, and first molar as well as the bone holding them together including a small piece of palate.Keith A. 1927. Report on a fragment of a human jaw found at a depth of (10 1/2 ft) 3.2 m in the cave earth of the vestibule of Kent's Cavern. Trans Proc Torquay Nat Hist Soc 5: 1-2.
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The mandibular first molar is the tooth located distally from both the mandibular second premolars of the mouth but mesially from both mandibular second molars. It is located on the mandibular arch of the mouth, and generally opposes the maxillary first molars and the maxillary 2nd premolar. This arrangement is known as Class I occlusion. There are usually five well-developed cusps on mandibular first molars: two on the buccal, two lingual, and one distal.
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The orbits of L. conclucatus are small, suggesting diurnal habits. Inflated, low-crowned (bunodont) cheek teeth with short, rounded shearing crests, as well as premolar simplification and M3 size reduction, suggest fruit- or gum eating adaptations, as among many living callitrichines. Procumbent and slightly elongate lower incisors suggest this species could use its front teeth as a gouge, perhaps for harvesting tree gum. Estimates from jaw size suggest Lagonimico weighed about ,Pérez et al.
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A systemic review and meta- analysis showed a success rate of endocrowns varying from 94 to 100%. Analysis in posterior and anterior teeth demonstrated that endocrowns had higher fracture strength than conventional treatments. Another study showed that an endodontic crown preparation appeared acceptable for molar crowns but inadequate for premolar crowns. The longest duration of survival is for molar endocrowns is a 5-year clinical follow-up period, with success rate of 87.1%.
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The snouts for Basilosaurus and Rodhocetus are short and make up about half the length of the skull. Remingtonocetid snouts are quite narrow, which was clearly not the case for Ambulocetus. The mandibular symphysis of most mammals is at the midline of the jaw, but it extends much farther in archaeocetes; in Ambulocetus it reached the tailmost end of the first premolar. These suggest reinforcement of the jaw to withstand a strong bite force.
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Rodents of the superfamily Muroidea, which includes mice, rats, voles, hamsters, bamboo rats, and many other species, generally have three molars in each quadrant of the jaws. A few of the oldest species retain the fourth upper premolar, and some living species have lost the third and even the second molars. Features of the molar crown are often used in muroid taxonomy, and many different systems have been proposed to name these features.
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As is characteristic of apeomyines, Apeomyoides was a large eomyid with high-crowned cheekteeth and a large gap between the incisors and cheekteeth. Furthermore, the cheekteeth—premolars and molars—approach a bilophodont pattern, with two distinct lobes. Other features distinguish Apeomyoides from other apeomyines, including the rectangular shape of the cheekteeth. The fourth lower premolar (p4) is larger than the molars behind it and has two roots, while the lower molars have three.
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Similarly, the oldest apeomyine, Zophoapeomys, is smaller and has lower-crowned cheekteeth. The known material of Apeomyoides consists of a number of fragmentary mandibles (lower jaws) and isolated cheekteeth. The length of the first and second lower molars (m1 and m2) ranges from 1.74 to 2.58 mm, the width from 2.08 to 2.33 mm. The fourth upper premolar (P4) has not been recorded, but there is a specimen of its deciduous precursor (DP4).
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HERS is proven to be essential for root formation and maturation by directing the proliferation and differentiation of multipotent stem cells. The presence of dens evaginatus or dens invaginatus were the second most common etiology of pulp necrosis in immature teeth. Dens evaginatus is more common between these 2 dental anomalies. It is seen on clinical and radiographic examination as an additional cusp, typically projecting into the occlusal table of a mandibular premolar.
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The fruits are attractive to elephants, which disperse the seeds in their dung; the tree does not regenerate well in mature forest, but does so in clearings and alongside tracks. The Sanje mangabey in Tanzania also feeds on the fruit, cracking open the hard seeds with their powerful premolar teeth. At the Taï National Park on the Ivory Coast, chimpanzees consume a significant quantity of P. excelsa fruit.Gone Bi, Z. B., and Roman M. Wittig.
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The adult premolar teeth are smaller than their predecessors, primary first and second molars. Therefore, the space that is naturally created, is usually taken up by the movement of the permanent first molar moving mesially. Nance showed that the combined width of mandibular deciduous canines, first molar and second molar is on average 1.7mm greater than that of the permanent successors on one side. The maxillary arch occupies about 1mm on each quadrant.
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A fox's dentition, like all other canids, is I 3/3, C 1/1, PM 4/4, M 3/2 = 42. (Bat-eared foxes have six extra molars, totalling in 48 teeth.) Foxes have pronounced carnassial pairs, which is characteristic of a carnivore. These pairs consist of the upper premolar and the lower first molar, and work together to shear tough material like flesh. Foxes' canines are pronounced, also characteristic of a carnivore, and are excellent in gripping prey.
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Llanocetus (“Llano's whale”) is a genus of extinct toothed baleen whales from the Late Eocene of Antarctica. The type species, Llanocetus denticrinatus, reached gigantic proportions, with the juvenile specimen reaching an estimated in length; a second, unnamed species, known only from three isolated premolar teeth, reached an estimated total body length of up to . Like contemporary baleen whales, Llanocetus completely lacked baleen in its jaws. It was probably a suction feeder like the modern beaked and pygmy right whales.
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The description of the species was published in 2000 by researchers Peter F. Murray, working at the Museum of Central Australia and Dirk Megirian of the Northern Territory Museum. The holotype is fossilised material excavated at "Top Site" at the Bullock Creek fossil area, a partial left dentary with a premolar and several molars that is dated to the mid-Miocene. The specific epithet commemorates Tom Rich, who introduced the authors to the site of their discovery.
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In appearance it resembled a dog with a long snout. Its molar teeth were specialized for carnivory; the cups and crest were reduced or elongated to give the molars a cutting blade. W. ridei is known from a right maxillary fragment (QMF 16851) containing molars one and two to the anterior section of the infraorbital foramen that was dorsal to the third molar. The left dentary fragment (QMF 16852) contains a partial second premolar and a full third molar.
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One, a fragmentary molariform (molar or molar-like premolar—the identities of gondwanathere tooth are poorly understood) is larger and lower-crowned than the Lavanify teeth and the other, which is complete and unworn, is yet lower-crowned and has the surface obliquely oriented. Its crown consists of a W-shaped ridge with the parts separated by deep infundibula. This second tooth may also represent a completely different, yet unknown mammalian group.Krause, 2000; Krause et al.
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The dental formula was typical of the artiodactyls with three incisors, a canine, four premolars and three molars; the first lower premolar was present in young people and, growing up, was expelled due to the growth of the canine. The upper molars were square in shape and equipped with four large conical cusps, surrounded by sturdy precing and postcingulation and extraordinarily thickened enamel. One particular species (A. frendi) still possessed protoconule and hypoconus, which disappeared in the other achenodonts.
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Triaenops goodmani is known from three mandibles (lower jaws): one with the fourth premolar (p4) and first and second molars (m1–2) and two with the second and third molars (m2–3). The jaw is relatively robust. The p4 resembles a canine, having a single cusp that is about as high as the highest cusp on m1 and lacking accessory shelves or cusps. The molars are narrow-crowned and longer than in T. menamena, P. auritus, and P. furculus.
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The inferior alveolar nerve is a branch of the mandibular nerve. After branching from the mandibular nerve, the inferior alveolar nerve travels behind the lateral pterygoid muscle. It gives off a branch, the mylohyoid nerve, and then enters the mandibular foramen. While in the mandibular canal within the mandible, it supplies the lower teeth (molars and second premolar) with sensory branches that form into the inferior dental plexus and give off small gingival and dental nerves to the teeth.
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Sakis and uakaris have a diastema between the canine and premolar teeth, but the titis, which have unusually small canines for New World monkeys, do not. All species have the dental formula: Females give birth to a single young after a gestation period of between four and six months, depending on species. The uakaris and bearded sakis are polygamous, living in groups of 8-30 individuals. Each group has multiple males, which establish a dominance hierarchy amongst themselves.
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Remains of this species include over 100 teeth, (upper and lower), and at least one fragment of jaw. The teeth range from in length. The fourth lower premolar (p4) is about 51% shorter than the corresponding tooth in P. mediaevus; 28% less than P. kummae; 15% less than P. tsosiensis; and 5% smaller than P. fractus, which gives some idea of the relative sizes of the various animals. There are also differences in shape and the number of serrations.
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The skull is specific in many ways; first, the infraorbital foramen is greatly enlarged so portions of the masseter extend through it and attach from the frontal side surface of the snout. Second, the angular process is inflected on the lower jaw, and third, the nasal cavity is enlarged. Prominent pockets create enlarged areas of attachment for chewing muscles. Collar bones are very much reduced, and one incisor, one premolar and three molars are present in each quadrant.
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Carnassials of a dog Carnassials are paired upper and lower teeth (either molars or premolars and molars) modified in such a way as to allow enlarged and often self-sharpening edges to pass by each other in a shearing manner. The modification arose separately in several groups of carnivorous mammals. Different pairs of teeth were involved in the separate modifications. In modern Carnivora, the carnassials are the modified fourth upper premolar and the first lower molar.
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Otarocyon ("large eared dog") is an extinct genus of the Borophaginae subfamily of canids native to North America. Ot lived during the Oligocene epoch, about 33.3—20.6 Ma (million years ago).PaleoBiology Database: Otarocyon Taxonomy, Species Fossils have been found only in Montana, Wyoming, and South Dakota. Otarocyon was a small borophagine characterized by a short, broad skull, a specialized middle ear, simple, tall premolar teeth, and molars that are incipiently adapted to a hypocarnivorous diet.
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Skull of A. malacorhinus On the basis of skull size, the largest species of Aphelops is A. mutilus (which is the largest North American rhinoceros) and the smallest is the type species A. megalodus. A. mutilus has been estimated to have weighed , and A. malacorhinus has been estimated at . Aphelops can be distinguished by other members of the Aceratheriinae by two traits: the arched top of the skull, and the long diastema (gap) between the second incisor (lower tusk) and first premolar. Many other aspects of its anatomy are typical of aceratheriines, including: the absence of a horn on the broad, unfused nasal bones; the reduced premaxilla and lost first incisor; a nasal incision (or notch below the nasal bones) reaching at least the level of the fourth premolar; a triangular-shaped skull when viewed from the rear; narrow zygomatic arches; brachydont or low-crowned teeth without cement; upper molars bearing a fold of enamel known as an anterocrochet; and lower tusks that are subcircular in cross-section.
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The teeth of KT12/H1 are quite similar to the jawbone of A. afarensis, with large and incisor-like canines and bicuspid premolars (as opposed to molar-like premolars). Unlike A. afarensis, the alveolar part of the jawbone where the tooth sockets are is almost vertical as opposed to oblique, possesses poorly developed superior transverse torus and moderate inferior torus (two ridges on the midline of the jaw on the tongue side), and thin enamel on the chewing surface of the premolars. Brunet and colleagues had listed the presence of 3 distinct tooth roots as a distinguishing characteristic, but the third premolar of the A. afarensis LH-24 specimen from Middle Awash, Ethiopia, was described in 2000 as having the same feature, which shows that premolar anatomy was highly variable for A. afarensis. The mandibular symphysis (at the midline of the jaw) of KT40, especially, as well as KT12/H1 have the same dimensions as the symphysis of A. afarensis, though theirs is relatively thick compared to the height.
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A study published by Ghosh et al. in 1996 stated that the mean maxillary first molar distalization was 3.37 mm, with a distal tipping of 8.36° and the mean reciprocal mesial movement of the first premolar was 2.55 mm, with a mesial tipping of 1.29°. They also stated that the eruption of maxillary second molars had minimal effect on distalization of first molars. In addition, the reported increase of Lower Anterior Facial Height for patient's who had pre-existing vertical growth.
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In the Palmer notation, a number is used in conjunction with a symbol designating in which quadrant the tooth is found. For this tooth, the left and right first premolars would have the same number, "4", but the right one would have the symbol, "┐", over it, while the left one would have, "┌". The international notation has a different numbering system than the previous two, and the right permanent mandibular first premolar is known as "44", and the left one is known as "34".
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The incisors are reduced and the canines appear to have functioned like cheek teeth (premolars and molars). The premolars are high-crowned, and the fourth premolar is very molar-like. The molars are the largest of any known ape, and have a relatively flat surface. Gigantopithecus had the thickest enamel by absolute measure of any ape, up to 6 mm (a quarter of an inch) in some areas, though was only fairly thick when tooth size is taken into account.
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For this tooth, the left and right second premolars would have the same number, "5", but the right one would have the symbol, "┐", over it, while the left one would have, "┌". The international notation has a different numbering system than the previous two, and the right permanent mandibular second premolar is known as "45", and the left one is known as "35". It is a very common condition in orthodontics for a patient to have one or both mandibular second premolars congenitally absent.
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Cleopatrodon, like all ptolemaiids, can most easily be identified from its unusual teeth. They were quite unspecialised at the anterior end of the mouth, with canines and incisors of a similar size, but the premolars and molars are very unusual. There are four premolars, rather than three as in most mammals, and three molars. In the lower jaw the premolars increased in size from premolar 1 to 4, and the molars decreased from 1 to 3, creating a smooth curve.
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The ezo red fox is somewhat larger than the Japanese red fox found in Honshu, Shikoku and Kyushu, and the outer part of the ear and the limbs are black. There are many similarities with continental red foxes. The ezo red fox has 42 teeth: 6 incisors, 2 canine teeth, 8 premolar, 4 upper molar and 6 lower molars. Ezo foxes normally have eight nipples: a pair on the chest; two pairs in the abdomen; and one pair in the groin.
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Megaconus is one of the few early mammaliaforms known from a complete skeleton. The skeleton includes both the jaw bones and the teeth, which are the most informative features because they allow for comparisons with other mammaliaforms known only from dental features. Megaconus has a dentition similar to those of rodents, with large incisors at the front of the jaws and broad molars in the back. One distinguishing feature of Megaconus is a pair of enlarged premolar teeth in the lower jaw.
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218 Skull of a specimen caught in Slovakia, redrawn from Benda et al. (2003a) The skull is similar in shape to that of M. mystacinus and M. brandtii, but the front part of the braincase is higher. The second and third upper premolars (P2 and P3) are tiny and pressed against the upper canine (C1) and fourth premolar (P4). The canine is less well-developed than in M. mystacinus. There is a clear cusp present on the side of the P4.
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Carpolestidae is a family of primate-like Plesiadapiformes that were prevalent in North America and Asia from the mid Paleocene through the early Eocene. Typically, they are characterized by two large upper posterior premolars and one large lower posterior premolar. They weighed about 20-150g, and were about the size of a mouse. Though they come from the order, Plesiadapiformes, that may have given rise to the primate order, carpolestids are too specialized and derived to be ancestors of primates.
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There are currently four valid species within the genus Ignacius: I. frugivorus, I. fremontensis, I. clarkforkensis, and I. graybullianus. There are also at least two undescribed species of Ignacius from the Arctic of Canada. The type species for the genus Ignacius is I. frugivorus and was found at the Mason Pocket locality in Colorado. The holotype specimen (AMNH 17368), published in 1921 by Matthew and Granger, consists of an upper jaw with the canine, fourth premolar, first molar, and second molar.
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In the Palmer notation, a number is used in conjunction with a symbol designating in which quadrant the tooth is found. For this tooth, the left and right first premolars would have the same number, "4", but the right one would have the symbol, "┘", underneath it, while the left one would have, "└". The international notation has a different numbering system than the previous two, and the right permanent maxillary first premolar is known as "14", and the left one is known as "24".
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Rubber dam isolation of upper left second premolar, held in place with a rubber dam clamp during endodontic therapy. The technique used to apply the dental dam is selected according to the tooth requiring treatment. Several techniques can be used including single tooth isolation, multiple tooth isolation or split dam technique. The dental dam is prepared by punching one or more holes in the dental dam sheet to enable isolation of the appropriate number of teeth required for the dental procedure.
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A ptilodont that throve in North America was Ptilodus. Thanks to the well-preserved Ptilodus specimens found in the Bighorn Basin, Wyoming, we know that these multituberculates were able to abduct and adduct their big toes, and thus that their foot mobility was similar to that of modern squirrels, which descend trees head first. Restoration of Catopsbaatar In Europe, another family of multituberculates were equally successful--the Kogaionidae, first discovered in Haţeg, Romania. They also developed an enlarged blade-like lower premolar.
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The species name is based on the confluent morphology of the teeth. The catalogue number for the skull is AMNH 26660, and it specifically preserved a "front half of the skull and a complete lower jaw, with most of the teeth and remaining alveoli, totaling a full placental series". Other remains included a portion of the mandible and a premolar. All of these specimens were from the lame locality, the Upper Gray Clays, of the Irdin Manha Formation in Inner Mongolia.
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In order to fully understand the development of occlusion and malocclusion, it is important to understand the premolar dynamics in the mixed dentition stage. The mixed dentition stage is when both primary and permanent teeth are present. The permanent premolars erupt ~9–12 years of age, replacing the primary molars. The erupting premolars are smaller than the teeth they are replacing and this difference in space between the primary molars and their successors (1.5mm for maxillary, 2.5mm for mandibular), termed Leeway Space.
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The skull and dentary exhibit extreme thickening (pachyostosis) somewhat similar to that in Megaloceros, unlike Megaloceros, the vomer is largely unaffected. The pachyostosis is among the most extreme of any known mammal. The upper canines are absent (there are no sockets for them present on the Aïn Bénian skull) and the lower fourth premolar (P4) is molarised. The preserved proximal portion of the antler is straight and cylindrical in cross section, and orientated anteriorly, laterally and slightly dorsally, the antler becomes flattened distally.
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Lagrivea is a fossil genus of squirrel from the Middle Miocene of France. The single species, L. vireti, is known from three mandibles (lower jaws) and two isolated teeth. All come from the fissure filling (a fossil deposit formed when a rock fissure filled with sediment) of La Grive L5, part of the La Grive-Saint-Alban complex in Saint-Alban-de-Roche, southeastern France. Lagrivea was a large tree squirrel with flat lower incisors and a large, triangular fourth lower premolar (p4).
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In life the victim was a size 12 and her height was between 5 ft 1in and 5 ft 7in. She was probably European but possibly from India or the Middle East. The victim had a number of fillings and her first upper right premolar was missing, which would have been apparent in life when she smiled. The victim was wearing a blue jumper, blue brassiere, a green pinafore dress and black stiletto court shoes (of which only one was found).
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The toothcombs in most mammals include incisors only, while in lemuriform primates they include incisors and canine teeth that tilt forward at the front of the lower jaw, followed by a canine-shaped first premolar. The toothcombs of colugos and hyraxes take a different form with the individual incisors being serrated, providing multiple tines per tooth. The toothcomb is usually used for grooming. While licking the fur clean, the animal will run the toothcomb through the fur to comb it.
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The third upper molar (M3) is more reduced in the false potto than in any other prosimian, according to Schwartz, but Leon notes that western pottos also have a relatively small M3. The third upper premolar (P3) is also reduced, resembling the condition in the fork- marked lemurs (Phaner). Stump writes that small P3s are also common in western pottos, although the false potto's P3 is shaped differently. Groves notes that P1 is quite long, another point of similarity with the fork-marked lemurs.
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An isolated canine from Thẩm Khuyên Cave, Vietnam, and a fourth premolar from Pha Bong, Thailand, could possibly be assigned to Gigantopithecus, though these could also represent the extinct orangutan Pongo weidenreichi. Two mandibular fragments each preserving the last 2 molars from Semono in Central Java, Indonesia, described in 2016 could represent Gigantopithecus. The oldest remains date to 2 million years ago from Baikong Cave, and the youngest 380,000–310,000 years ago from Hei Cave. In 2014, a fourth confirmed mandible was discovered in Yanliang, Central China.
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Argentodites is a possible multituberculate mammal from the Cretaceous of Argentina. The single species, Argentodites coloniensis, is known from a single blade-like fourth lower premolar (p4) from the La Colonia Formation, which is mostly or entirely Maastrichtian (latest Cretaceous) in age. The p4 is 4.15 mm long and bears eight cusps on its upper margin and long associated ridges on both sides. The enamel consists of prisms that are completely or partly surrounded by a sheath and that are on average 6.57 μm apart.
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Turner's hypoplasia is an abnormality found in teeth. Its appearance is variable, though usually is manifested as a portion of missing or diminished enamel on permanent teeth. Unlike other abnormalities which affect multiple teeth, Turner's hypoplasia usually affects only one tooth in the mouth and, it is referred to as a Turner's tooth. If Turner's hypoplasia is found on a canine or a premolar, the most likely cause is an infection that was present when the primary (baby) tooth was still in the mouth.
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Specimens of Dralestes are now recognized as being either Azibius and Algeripithecus, and Tabuce et al. claimed that Dralestes was a synonym of Azibius in 2009. However, in 2010, Godinot cautiously suggested that Dralestes may be a synonym of Algeripithecus based on a blade-like premolar. He also reasserted his view that Algeripithecus was a simian based on its upper molar morphology and hypothesized that this applied to all azibiids, favoring his earlier view that they may be early simians instead of stem lemuriforms.
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Another genus known from a single tooth (in this case, a fourth lower premolar), Argentodites, was first described as an unrelated multituberculate, but later identified as possibly related to Ferugliotherium. Finally, a single tooth from the Paleogene of Peru, LACM 149371, perhaps a last upper molariform, and a recent specimen from Mexico,SVP 2015 may represent related animals. Ferugliotheriids are known from isolated, low- crowned (brachydont) teeth and possibly a fragment of a lower jaw. Ferugliotherium is estimated to have weighed 70 g (2.5 oz).
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Graecopithecus tooth (Azmaka, Bulgaria) The original Graecopithecus specimen mandible was found in 1944, "reportedly unearthed as the occupying German forces were building a wartime bunker". The mandible with a third molar that is very worn, the root of a second molar, and a fragment of a premolar is from a site called Pyrgos Vassilissis, northwest of Athens and is dated from the late Miocene. Excavation of the site is not possible (as of 1986) due to the owner having built a swimming pool on the location.
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T. goodmani is identifiable as a member of Triaenops or the related genus Paratriaenops by a number of features of the teeth, such as the single-cusped, canine-like fourth premolar and the presence of a gap between the entoconid and hypoconulid cusps on the first two molars. T. goodmani is larger than the living species of Triaenops and Paratriaenops on Madagascar, and on the first molar the protoconid cusp is only slightly higher than the hypoconid, not much higher as in the other species.
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They said that various features of H. floresiensis are diagnostic characteristics, such as enlarged pituitary fossa, unusually straight and untwisted humeral heads, relatively thick limbs, double rooted premolar, and primitive wrist morphology. However, Falk's scans of LB1's pituitary fossa show that it is not larger than usual. Also, in 2009, anthropologists Colin Groves and Catharine FitzGerald compared the Flores bones with those of ten people who had had cretinism, and found no overlap. Obendorf and colleagues rejected Groves and FitzGerald's argument the following year.
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The middle part of the palate is concave, not flat as in M. aelleni and M. manavi. At the palate's back margin is a long, thin posterior palatal spine. Miniopterus mahafaliensis has 36 teeth in the dental formula (three incisors, one canine, three premolars, and two molars in both upper toothrows and two incisors, one canine, two premolars, and three molars in the lower toothrows). As is characteristic of Miniopterus, the first upper premolar (P1) is smaller and more simplified than the second (P2).
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The tooth at the end of each region was less genetically stable and hence more prone to absence. In contrast, the tooth most mesial in each region seemed to be more genetically stable. A subsequent theory hypothesised the teeth at the end of each region were possibly “vestigial bodies” that became obsolete during the evolutionary process. At present, it has been theorised that evolutionary change is working to decrease the human dentition by the loss of an incisor, premolar and molar in each quadrant.
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They have two tiny, vestigial premolars between the upper canines and first large premolar. Unlike other bats, they lack a tendon-locking mechanism in their toes. The common name bent-winged bat refers to their most obvious feature, the group's ability to fold back an exceptionally long third finger when the wings are folded. This finger gives the bats long, narrow wings that allows them to move at high speed in open environments and in some species to migrate over a distance of hundreds of kilometres.
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Diagram of a wolf skull with key features labelled Merriam named 3 unusual species based on specimens recovered from the Rancho La Brea tar pits. They were regarded by Nowak as taxonomic synonyms for Canis lupus. Canis occidentalis furlongi (Merriam 1910) was described as a wolf considerably smaller than the dire wolf and more closely related to the timber wolf Canis lupus occidentalis. However, its premolar P4 (upper carnassials) were massive, and the hypocone of the molar M1 was larger than that of the dire wolf.
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A true Hairless often does not have as much furnishings (hair on the head, tail, and paws). The difference between a very hairy Hairless and a Powderpuff is that the Hairless has a single coat with hairless parts on the body, while the Powderpuff has a thick double coat. The skin of the Hairless comes in a variety of colors, ranging from a pale flesh to black. Hairless Chinese Crested Dogs often lack a full set of premolar teeth, but this is not considered a fault.
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Krause and colleagues identified a single tooth, MACN Pv-RN 251, as a possible deciduous anterior (i.e., not p4 or dp4, the deciduous version of p4) lower premolar of Ferugliotherium. It is minuscule, with a length of 0.85 mm and width of 0.5 mm (assuming the tooth is oriented correctly). It bears two serrations (small projections) at the tip of the crown—one around the middle of the crown and the other at what may be the back of the crown, where it is highest.
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Bonaparte had identified another tooth, MACN Pv-RN 252, as a possible Ferugliotherium lower premolar in 1990, but this fossil is very fragmentary and according to Krause and colleagues, it cannot even be proven to be a mammalian tooth. Krause and colleagues identified two teeth, MACN Pv- RN 249 and 250, as anterior upper premolars. 249 bears two longitudinal rows of cusps. One row (row A; possibly the lingual one) includes four cusps, the other (row B) includes at least two, but is damaged.
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The peculiar shape of their last lower premolar is their most outstanding feature. These teeth were larger and more elongated than the other cheek-teeth and had an occlusive surface forming a serrated slicing blade. Though it can be assumed that this was used for crushing seeds and nuts, it is believed that most small multituberculates also supplemented their diet with insects, worms, and fruits. Tooth marks attributed to multituberculates are known on Champsosaurus fossils, indicating that at least some of these mammals were scavengers.
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Heishanobaatar is an extinct genus of eobaatarid multituberculate which existed in Shahai and Fuxin formations, northeastern China, during the early Cretaceous (Aptian/Albian age). It was first named by Nao Kusuhashi, Yaoming Hu, Yuanqing Wang, Takeshi Setoguchi and Hiroshige Marsuoka in 2010 and the type species is Heishanobaatar triangulus. Known from dentaries, lower incisors, and premolars, Heishanobaatar is distinguished by its laterally triangular third premolar, from which its species name is derived. Its referral to Eobaataridae was considered questionable by Kusuhashi et al 2019.
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For comparison, the left first incisor is . The premolars are elongated, and the protoconid (the cusp on the tongue side) of the third premolar is oriented more cheekwards, which is a distinguishing characteristic of Miocene African apes from Miocene Eurasian apes. Compared to African apes contemporary with Nakalipithecus, the tooth enamel on the molars is thinner, and the cusps (which project outward from the tooth) are less inflated, creating a wider basin. In the holotype, the first, second, and third molars are , , and , respectively.
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Tsagandelta is currently known from one specimen, the holotype PSS-MAE 629. This specimen is composed of a left dentary fragment containing an almost intact second molar, the base of the third molar and the roots of the first premolar; various other tooth sockets are empty, and the dental formula is probably similar to that of Deltatheridium. Based on comparisons with the related Lotheridium, the preserved dentary indicates that Tsagandelta was slightly smaller than the former; Lotheridium is about the size of a modern marten.
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In 2003 another human species was found at Liang Bua cave in Flores, eastern Indonesia. The fossils consist of cranial and some post-cranial remains of one individual, and a premolar from another individual in older deposits. The species was recognized as distinct from H. erectus and H sapiens on the basis of anatomical differences (including much smaller body size), and named Homo floresiensis. It has been suggested that the brain volume of these individuals was approximately around 400 cm3, similar to the African Australopithecus afarensis.
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The maxillary sinus is known for its thin floor and close proximity to the posterior maxillary (upper) teeth. The extraction of a maxillary tooth (typically a maxillary first molar which lies close to the lowest point of antral floor although any premolar or molar can be affected) is the most common cause of an OAC (which can then progress to an OAF as described above). Extraction of primary teeth are not considered a risk of OAC due to the presence of developing permanent teeth and the small size of the developing maxillary sinus.
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These traits are too numerous to have been easily developed by parallel evolution. In the taxa's four premolars, double rooted second premolar and unreduced canine and last molar, the teeth of Altanius are too primitive to be omomyoids, best resembling the Carpolestidae, a group of Plesiadapiformes. The dentition is also not dissimilar from primitive adapoids Donrusselia and Cantius. However, its high lingual cusps and short talonids, the basin at the distal end of the lower molars, are traits too derived for this specimen to be a primitive omomyoid ancestor.
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Neanderthal tooth on display at an exhibition in conjunction with 17th annual conference of Iranian Archaeology held at Iran National Museum, February 2020 Neanderthal from the Central Western Zagros, Iran. Structural reassessment of the Wezmeh 1 maxillary premolar. Journal of Human Evolution, Vol: 135. A lifelike model of a Neanderthal child, Museum of Persian Gulf, Bandar Abbas, Iran Given that the cave was a carnivore den during late Pleistocene, it is probable that the Wezmeh Child was killed, or had its remains scavenged, by carnivores who used the cave as den.
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The mental foramen (an opening at the outer side of the jaw) is located between the lower canine and second lower premolar (p2). The coronoid process (a projection at the back of the mandible) is low and rounded and is connected to the condyloid process behind it by a nearly horizontal ridge, which contains a slight raising at its back. Compared to M. schreibersii, the condyloid process is more slender, but the base of the angular process (at the lower back corner of the jaw) is more robust.Wołoszyn, 1986, p.
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The creodont lumbosacral spine was not arranged as efficiently for running as in Carnivora. The arrangement of the teeth was also somewhat different. In the miacids (as with the modern Carnivora), the last upper premolar and the first lower molar are the carnassials, allowing grinding teeth to be retained behind for feeding on non- meat foods (the Canidae are the closest modern analog to miacid dentition). In creodonts, the carnassials were further back—either the first upper and second lower molars, or the second upper and third lower molars.
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Report of Investigations, University of Texas Bureau of Economic Geology 48: 1–75. is another extinct Late Pleistocene coyote that once inhabited what is now Texas. Slaughter described it as being wolf-like and was distinguished from other coyotes by a well-developed posterior cusp on its p2 (the second premolar on its mandible), a longer tooth row relative to the depth of its mandible, a reduced distance between premolars, and a more vertical descending ramus. The cusp dentition was also found in two specimens from Mexico and one from Honduras.
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Premolar 3 and molars one and two are missing with the alveolus intact, mo material remains after molar three. Muirhead (1997 p. 372) describes W. ridei as having the following features that are unique: parametacrista on the first molar is straight, entoconid either missing of combined with the hypoconid in a more posterior position, the loss or reduction of styler crests, small metaconid, talonid basin reduced by the lingual (toward the tongue) placement of the hypoconid. Dasyurid type features include the infraorbital foramen away from the jugal and a large hypoconid.
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All of the terrestrial species of carnivorans have three incisors on the top and bottom row of the dentition (the exception being is the sea otter (Enhydra lutris) which only has two lower incisor teeth). The third molar has been lost. The carnassial pair is made up by the fourth upper premolar and the first lower molar teeth. Like most mammals the dentition is heterodont in nature, though in some species like the aardwolf (Proteles cristata) the teeth have been greatly reduced and the cheek teeth are specialised for eating insects.
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A fossil species described by Neville Pledge in a study published in the records of the South Australia Museum in 1977. The holotype is a third premolar, discovered at a cave in Curramulka in South Australia, exhibiting the carnivorous characteristics of the genus and around half the size of Thylacoleo carnifex. This tooth was collected by Alan Hill, a speleologist and founding member of the Cave Exploration Group of South Australia, while examining a site known as the "Town Cave" in 1956; the specific epithet hilli honours the collector of the first specimen.
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The following year, Krause confirmed that Vucetichia gracilis is a synonym of Ferugliotherium windhauseni. Together with Bonaparte, he also proposed to classify gondwanatheres as a superfamily (Gondwanatherioidea) within Plagiaulacoidea, including the families Ferugliotheriidae and Sudamericidae. In 1996, Kielan-Jaworowska and Bonaparte tentatively identified a lower jaw fragment with a multituberculate-like fourth lower premolar (p4) from Los Alamitos as Ferugliotherium. On the basis of the morphological features of the jaw fragment, they argued that gondwanatheres are not closely related to any other multituberculate group, and consequently placed them in a suborder of their own, Gondwanatheria.
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Figure 2. Generalized australosphenidan lower molar seen from above, illustrating major features. Abbreviations: ant, anterior (towards the front); pos, posterior (towards the back); ci, cingulum; pa, paraconid; pr, protoconid; me, metaconid; dm, distal metacristid; co, cristid obliqua; hy, hypoconid; hl, hypoconulid; ec, entocristid; tb, talonid basin. Ambondro was described on the basis of a fragmentary right mandible (lower jaw) with three teeth in it (Figure 1), interpreted as the last premolar (p-last) and the first two molars (m1 and m2). It is in the collection of the University of Antananarivo as specimen UA 10602\.
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Structural reassessment of the Wezmeh 1 maxillary premolar. Journal of Human Evolution, Vol: 135. Evidence from later Upper Paleolithic and Epipaleolithic occupations come from Yafteh Cave, Kaldar Cave near Khoramabad, and Warwasi, Malaverd near Kermanshah, Kenacheh Cave in Kurdistan, Boof Cave in Fars and a number of other caves and rock shelters.Shidrang S, (2018) The Middle to Upper Paleolithic Transition in the Zagros: The Appearance and Evolution of the Baradostian, In The Middle and Upper Paleolithic Archeology of the Levant and Beyond, Y. Nishiaki, T. Akazawa (eds.), pp.
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A. deyiremeda features a strong jawbone and thick enamel, consistent with a diet of tough sedges and similar foods which australopiths are generally thought to have primarily subsisted upon. The enamel on the upper incisor, canine, and first premolar exhibits hypoplasia, probably caused by a period of malnutrition or illness during enamel growth in infancy while the teeth were still growing. A. deyiremeda was likely a generalist feeder. If A. deyiremeda is indeed distinct from A. afarensis, then these two species may have exhibited niche partitioning given they cohabited the same area.
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The toothcomb is kept clean using a sublingual organ—a thin, flat, fibrous plate that covers a large part of the base of the tongue. The first lower premolar (p2) following the toothcomb is shaped like a canine (caniniform) and occludes the upper canine, essentially filling the role of the incisiform lower canine. There is also a diastema (gap) between the second and third premolars (p2 and p3). The upper incisors are small, with the first incisors (I1) space widely from each other, yet closely to the second incisors (I2).
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Their tendency to grow in size may also contribute to periodontal disease as a result of food build up in the area of the lesion. Radiographically, buccal exostoses can be identified as round, well-defined structures which superimpose the roots of the teeth, normally in the premolar and molar region. Dental panoramic tomography and cone beam tomography can be used to confirm diagnosis. An additional biopsy for diagnosis of buccal exostosis is not usually recommended, however it is important to rule out the possibility of early osseosarcomas and chondrosarcomas.
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Studies on juvenile Hyaenodon specimens show that the animal had a very unusual system of tooth replacement. Juveniles took about 3–4 years to complete the final stage of eruption, implying a long adolescent phase. In North American forms, the first upper premolar erupts before the first upper molar, while European forms show an earlier eruption of the first upper molar.Katharina Anna Bastl, First evidence of the tooth eruption sequence of the upper jaw in Hyaenodon (Hyaenodontidae, Mammalia) and new information on the ontogenetic development of its dentition, Paläontologische Zeitschrift (Impact Factor: 1.1).
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Similarly, the strongest biting muscle in Ambulocetus seems to have been the temporalis muscle involved in biting down. Like other cetaceans, there are embrasure pits (a depression between the teeth), preserving the tooth positions for the fourth premolar, the first molar, and the third molar. Unlike later archaeoecetes, the roots of the molars do not extend to the cheek bones, and the third molar is not as nosewards as in remingtonocetids. The coronoid process of the mandible (where the lower jaw connects with the skull) in Ambulocetus is steep.
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This tooth is characterized by four major cusps (protocone, paracone, hypocone, and metacone) and lophs or crests (protoloph, mesoloph, metaloph, and posteroloph), separated by synclines or valleys. The first and second upper molar (M1 and M2) are almost square and similar in size and structure to the DP4. An additional loph on M1 and M2, the entoloph, is incomplete in Apeomyoides, but more prominent in both Megapeomys bobwilsoni and Arikareeomys. The four lower cheekteeth—the fourth lower premolar (p4) and first through third lower molars (m1–m3)—are high-crowned teeth.
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In a Science report in 1995 upon the finding several doubts were raised including one by Milford Wolpoff > Milford Wolpoff of the University of Michigan, who saw the specimens on a > trip to China several years ago, isn't even convinced that the partial jaw > is a hominid. "I believe it is a piece of an orangutan or other Pongo," he > says. He bases that conclusion on a wear facet on the preserved premolar, > which to him suggests that the missing neighboring tooth is shaped more like > an orang's than a human's.Culotta E. (1995).
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Location of a dog's carnassials; the inside of the 4th upper premolar aligns with the outside of the 1st lower molar, working like scissor blades Isotopic bone collagen analysis of the specimens indicated that they ate horse, bison, woodland muskox, and mammoth — i.e., Pleistocene megafauna. This supports the conclusion that they were capable of killing and dismembering large prey. Compared with Pleistocene and extant gray wolves, the megafaunal wolf was hypercarnivorous, with a craniodental morphology more capable of capturing, dismembering, and consuming the bones of very large mega-herbivores.
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Their muzzles are distinguished as broad and convex, and tapering out toward the end. The top of the snout is covered in short and fine fur, interspersed with short whiskery vibrissae, although not the longer bristles found in the related species Setirostris eleryi (Mormopterus eleryi). With an exception in several of the species, and especially Ozimops halli, the dental formula is 1/2, 1/1, 2/2, 3/3 = 30. The variation to this is the loss of a tooth in mature individuals, the upper anterior premolar, at one or both sides of the jaw.
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Thylophorops species (as well as several other contemporary opossum genera) show a high degree of speciation towards carnivory compared to most living didelphines. Their premolar and molar teeth were proportionally larger than those of living opossums and their grinding facets imply a more dedicated shearing action; these have been interpreted as "omnivory leading towards carnivory" and as more specialized carnivory in posterior studies. There is evidence that T. chapadmalensis re-appropriated burrows from other digging mammals, as well as outright consuming them. Thylophorops species as a whole tended to be terrestrial rather than arboreal.
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This specimen, a fragment of maxilar with a premolar (P4) and the first upper molar (M1) is catalogued as SGCMGJRG2018.V.7 and is housed in the Geological Museum Jose Royo y Gómez, which were donated by the discoverers of the specimen, Hasmet Florián and José Martínez. The site belongs to the Miocene but without a precise datation; the characteristics of the teeth support the assignation to Hilarcotherium, but since that it shows some differences with the recognised species of the genus, is only classified as Hilarcotherium sp.Jaramillo, M. P. (2018).
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The jaw missing the incisors, the crown of the fourth premolar and the left mandibular ramus, but has the roots of the teeth of the right side and a broken canine with an oval cross section. It has however the sockets for three incisors on each side of the jaw, which is a plesiomorphic feature, as his other relatives as Xenastrapotherium had two. In 2018, Carillo et al. described a partial skull and mandibule of a second species H. miyou from the Castilletes Formation in the Cocinetas Basin of northern Colombia.
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The original remains of Pyrotherium, some molars, a premolar and an incisor, were originally identified in the Neuquén province in strata dating back to the late Oligocene epoch, identified by the Argentine naturalist Florentino Ameghino as couche à Pyrotherium (layers of Pyrotherium, in French) due to the presence of fossils of this animal that were the first to be identified there;Ameghino, F. 1894. Première contribution à la conaissance de la faune mammalogique des couches à Pyrotherium. Boletín del Instituto Geográfico Argentino 15: 603–660.Ameghino C. 1914.
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Unlike mouse lemurs and more like dwarf lemurs, giant mouse lemurs have a prominent anterior lower premolar (P2). Also more aligned with dwarf lemurs, the first two upper molars (M1–2) have a more anterior hypocone that sits opposite the metacone, compared to the mouse lemurs' more posterior hypocone, which is presumably a symplesiomorphic (ancestral) trait. Also on M1 and M2, the cingulum (a crest or ridge on the tongue side) comprises two small cuspules. In all other dental characteristics, giant mouse lemurs are noticeably similar to both dwarf and mouse lemurs.
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In the mandible, M1 (molar tooth) is relatively larger than in any other canid species.Miyamoto F, Maki I (1983) On the repaired specimen of Japanese wolf (Canis lupus hodophilax Temminck) and its skull newly taken out. Bull Fac Ed Wakayama Univ Nat Sci 32: 9–16 (in Japanese with English abstract) An examination in 1991 found one specimen's condylobasal length (a measure of skull length) to be 205.2mm, and the Alveolar length of P4 (the fourth maxillary premolar or carnassial tooth) to be 20.0mm (left) and 21.0mm (right).Miyamoto, F. (1991).
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Their tails help to offset their balance while moving swiftly through the trees since their tails are about the same length as their head and body size. Sexual dimorphism is very low, with males and females being of about equal sizes. The upper and lower jaws of the Matschie's tree-kangaroos are different too in addition to them being different in body size. The upper jaw has three incisors, one canine, one premolar, and four molars, while the lower jaw has one very sharp incisor, no canines and low crowned molars.
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Afontova Gora II consists of 7 layers. Layer 3 from Afontova Gora II is the most significant: the layer produced the largest amount of cultural artefacts and is the layer where the human fossil remains were discovered. Over 20,000 artefacts were discovered at layer 3: this layer produced over 450 tools and over 250 osseous artefacts (bone, antler, ivory). The fossils of two distinct individuals were discovered in the initial excavations: the upper premolar of an 11-15 year-old child and the left radius, ulna, humerus, phalanx, and frontal bone of an adult.
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Indriidae are herbivores, eating mostly leaves, fruits, and flowers. Like some other herbivores, they have a large cecum, containing bacteria that ferment cellulose, allowing for more efficient digestion of plant matter. They have fewer premolar teeth than other lemurs, with the dental formula of: Females and males usually mate monogamously for many years. Mostly at the end of the dry season, their four- to five-month gestation ends with the birth of a single offspring, which lives in the family for a while after its weaning (at the age of five to six months).
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The Neanderthals who occupied the area were avid eaters of birds; 247 remains of 18 different bird species were found, especially doves and choughs. Bird consumption in Cova Negra and other caves such as Cueva de Bolomor, Gorham's Cave, and Ibex Cave, prove that the northwestern part of the Mediterranean saw widespread exploitation of "small, fast game". In 2013, a fragment from an adult parietal bone were found, a cranial fragment from a child, and a child's premolar. By that time, the cave had 25 pieces of Neanderthal remains (seven individuals in all), including many of children (one a teenager, four children).
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The mandibular (lower) teeth and their associated periodontal ligament are innervated by the inferior alveolar nerve, a branch of the mandibular division. This nerve runs inside the mandible, within the inferior alveolar canal below the mandibular teeth, giving off branches to all the lower teeth (inferior dental plexus). The oral mucosa of the gingiva (gums) on the facial (labial) aspect of the maxillary incisors, canines and premolar teeth is innervated by the superior labial branches of the infraorbital nerve. The posterior superior alveolar nerve supplies the gingiva on the facial aspect of the maxillary molar teeth.
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Clinical presentation of abfraction non-carious tooth tissue lesions on the cervical margins of upper left canine and premolar Abfraction is a theoretical concept explaining a loss of tooth structure not caused by tooth decay (non- carious cervical lesions). It is suggested that these lesions are caused by forces placed on the teeth during biting, eating, chewing and grinding; the enamel, especially at the cementoenamel junction (CEJ), undergoes large amounts of stress, causing micro fractures and tooth tissue loss. Abfraction appears to be a modern condition, with examples of non-carious cervical lesions in the archaeological record typically caused by other factors.
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In Old Crow region, Castoroides fossils occur in deposits of the Sangamonian interglacial. The discovery of giant beaver remains in New Brunswick adds significantly to the Quaternary terrestrial mammal fauna of New Brunswick, and suggests that the terrestrial fauna was probably richer than earlier evidence indicated. The known North American distribution of giant beaver is not significantly changed by this occurrence. Specimens from the southeastern US have been placed in a separate species, Castoroides dilophidus, based on differences in premolar and molar features. Martin (1969) considered it a subspecies, but new research by Hulbert et al.
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Further confusion may result if a number is given on a tooth without assuming (or specifying) a common notation method. Since the number, "12", may signify the permanent left maxillary first premolar in the universal system or the permanent right maxillary lateral incisor in the FDI system, the notation being used must be clear to prevent confusion. In 1891 Victor Haderup devised a variant of eight tooth quadrant system in which plus (+) and minus (-) were used to differentiate between upper and lower quadrants, and between right and left quadrants (e.g., +1 = upper right central incisor; 1- = lower left central incisor).
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Godinot saw similarities between Djebelemur and early simians, as well as cercamoniines, but also noted issues of premolar and molar compaction that set it apart from European adapiforms. In 1997, Hartenberger continued to favor adapiform affinities, while in 1998, Godinot considered affinities with lemuriforms ("crown strepsirrhines") while still favoring simian affinities, particularly with oligopithecids. By 2006, Godinot accepted Djebelemur as a stem lemuriform, admitting that he was misled by the lack of a toothcomb—a distinguishing dental feature of living lemuriform primates—despite other dental similarities. He also noted that the lower molars of lemuriforms and simians can be difficult to distinguish.
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The premolar and first molar together compose the carnassial pair on each side of the mouth, which efficiently shears meat into small pieces, like a pair of scissors. These are vital in feeding, since cats' small molars cannot chew food effectively, and cats are largely incapable of mastication. Although cats tend to have better teeth than most humans, with decay generally less likely because of a thicker protective layer of enamel, a less damaging saliva, less retention of food particles between teeth, and a diet mostly devoid of sugar, they are nonetheless subject to occasional tooth loss and infection.
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LiveScience likely in response to larger competitors and prey rather than Bergmann's rule. Their skulls and jaws were significantly thicker and deeper than in modern coyotes, with a shorter and broader rostrum and wider carnassial (denoting the large upper premolar and lower molar teeth of a carnivore, adapted for shearing flesh) teeth. These adaptions allowed it to cope with higher levels of stress, when it killed larger prey, compared to modern coyotes. Pleistocene coyotes were also likely more specialized carnivores than their descendants, as their teeth were more adapted to shearing meat, showing fewer grinding surfaces which were better suited for processing vegetation.
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Samonds, 2007, table 2 On the first upper molar (M1), the protofossa, a basin between cusps at the front of the tooth, is closed. The second molar (M2) is similar, but smaller and more squared. M3 is much smaller and has a reduced crown pattern resembling a W. The two incisors on each side of the lower jaw are small and have three cusps. The lower canine (c1) has one high and narrow cusp. The second lower premolar (p2) is a large tooth with a high central cusp and high crests connecting this cusp to the front and back edges.
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For the outer (facial) surfaces of all teeth, the height of curvature is located in the cervical third of the teeth. In the inner (lingual) surfaces of anterior teeth, both upper and lower, the height of curvature is also located in the cervical third of the tooth, on the cingulum. In the posterior teeth, both in upper and lower jaw, the lingual height of contour is found at the middle third of the inner surface of the tooth. The lower second premolar proposes an exception as its height of curvature in inner surface is located in the occlusal third of the inner surface.
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Unlike most species of the genus Galerix, G. kostakii has a fourth cusp, the hypocone, on its upper third premolar (P3). Galerix symeonidisi and Galerix iliensis also have this cusp, but are smaller and larger, respectively, than G. kostakii. In addition, G. kostakii differs from G. symeonidisi in that a connection between the protocone and metaconule cusps of M2 is more rarely present and the back arm of the metaconule always reaches the back corner of the tooth. Members of the related genus Parasorex are similar, but never have a protocone-metaconule connection, which is still occasionally present in G. kostakii.
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Reconstructed skull of Hilarcotherium castanedaii: the darker parts represents the fossils found The holotype specimen of Hilarcotherium castanedaii is named IGM p881231. This consists of fragments of skull, a partial jaw, the vertebral ramus of a dorsal rib, a complete left humerus and an incisor tooth associated. The skull includes the rostrum area, the palate with the fourth premolar (P4) and the three upper molars (M1-M2-M3) plus part of the zygomatic arch and the braincase, but lacks the upper canines and the top portion of the skull. The premaxilla shows no sign of having teeth, as in other astrapotheres.
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Multituberculate mastication is thought to have operated in a two stroke cycle: first, food held in place by the last upper premolar was sliced by the bladelike lower pre-molars as the dentary moved orthally (upward). Then the lower jaw moved palinally, grinding the food between the molar cusp rows. allodontid multituberculates The structure of the pelvis in the Multituberculata suggests that they gave birth to tiny helpless, underdeveloped young, similar to modern marsupials, such as kangaroos. At least two lineages developed hypsodonty, in which tooth enamel extends up beyond the gumline: lambdopsalid taeniolabidoideans and sudamericid gondwanatheres.
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The Hainina, the most successful genus, was originally believed to be a ptilodont. However, more detailed analysis of this genus revealed a smaller number of dental cusps and a retained fifth premolar--a unique combination of primitive and advanced features indicating that Hainina were related to some Jurassic genera and that enlarged, blade-like premolars were acquired independently in Europe and North America. Another group of multituberculates, the taeniolabids, were heavier and more massively built, indicating that they lived a fully terrestrial life. The largest specimens weighted probably as much as 100 kg, making them comparable in size to large rodents like Castoroides.
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Gazella psolea is an unusual prehistoric species of gazelle that lived in Africa and Arabia; it is only known from fossils. It makes up the subgenus Deprezia due to its unique skull morphology: it had a long premolar row, and its nasal area is peculiar, with short nasal bones and a very large nasal opening. It therefore seems to have been able to breathe cold and dry air (a similar adaptation as found in the saiga), but why this feature evolved is still rather mysterious. Perhaps it made seasonal migrations to the High Atlas mountains, where such an adaptation would have been useful.
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The genus Meles was erected by French zoologist Mathurin Jacques Brisson in 1762 after Carl Linnaeus had described the Eurasian badger Meles meles in 1758. This animal had a very extensive range over most of temperate Europe and Asia and there has been much discussion as to whether it is a single or three distinct species. There are geographical differences between individuals from different parts of the range in skull structure, morphology of the first premolar teeth, and facial markings. Some authorities advocated placing European and Asian badgers in separate species, Meles meles and Meles leptorhynchus (Milne-Edwards, 1867), the boundary between the two being the Volga River.
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The Espíritu Santo antelope squirrel (Ammospermophilus insularis) is a species of antelope squirrel in the family Sciuridae. It is endemic to Mexico, where it is known only from the island of Espíritu Santo in the Gulf of California. The species was originally described by Edward William Nelson and Edward Alphonso Goldman in 1909 as a subspecies of the white-tailed antelope squirrel (Ammospermophilus leucurus), a wide-ranging species in the southwestern U.S. and Mexico. In 1938, Arthur H. Howell elevated the subspecies to full species status, on the basis of slightly larger skull proportions and the absence or reduction of the third upper premolar.
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The false potto generally resembles a small potto, but according to Schwartz it differs in having a longer tail, shorter spines on its neck and chest vertebrae, a smaller, less complex spine on the second neck vertebra, an entepicondylar foramen (an opening in the humerus, or upper arm bone), a lacrimal fossa (a depression in the skull) that is located inside the eye socket, a smaller upper third premolar and molar, and higher-crowned cheekteeth, among other traits. However, many of these traits are variable among pottos; for example, one researcher found entepicondylar foramina in almost half of the specimens in his sample of pottos.
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By 1939, after purchasing more teeth, he determined they had originated somewhere in Guangdong or Guangxi. He could not formally describe the type specimen until 1952 due to his internment by Japanese forces during World War II. In 1955, a survey team led by Chinese palaeontologist Pei Wenzhong was tasked by the Chinese Institute of Vertebrate Paleontology and Paleoanthropology (IVPP) with finding the original Gigantopithecus locality. They collected 47 teeth among shipments of "dragon bones" in Guangdong and Guangxi. In 1956, the team discovered the first in situ remains, and third molar and premolar, in a cave (subsequently named "Gigantopithecus Cave") in Niusui Mountain, Guangxi.
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The tooth examined by Pledge in 1977 was obtained at vertical shaft in limestone formations on the Yorke Peninsula in South Australia in 1956. The cave had been subject to early excavations for the local supply of water, and in previous investigations had produced specimens of a diprotodont and skeleton of another species of the genus, Thylacoleo carnifex. The placement of the premolar is not associated with other Curramulka fossil fauna, although it is suggested to have been deposited during the Pliocene or an earlier period. Material found amidst the fauna at Bow River in New South Wales, dated to the early Pliocene, was also referred to the species in 1982.
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Likely due to different social structures, the Irish elk exhibits more marked sexual dimorphism than Alces, with Irish elk bucks being notably larger than does. In total, Irish elk bucks may have ranged from , with an average of , and does may have been relatively large, about 80% of buck size, or on average. The distingushing characters of M. giganteus include concave frontals, proportionally long braincase, proportionally short front section of the skull (orbitofrontal region), alongside the absence of upper canines and the molarisation of the lower fourth premolar (P4). The skull and mandible of the Irish elk exhibit substantial thickening (pachyostosis), with the early and complete obliteration of cranial sutures.
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Favorable eruption position of the second permanent molar may result if the first permanent molar is extracted when the child is at the age of between 8–10 years old. This is when the crown formation of the second permanent molar is complete and the mineralization of the bifurcation is commenced. Extraction of first permanent molars before 8 years old increases the chances of the unerupted second permanent premolar drifting distally. Extraction after the age of 10 years reduces the likelihood of the mesial movement of the second permanent molar in to the first permanent molar space and may result in tilting of the second permanent molar.
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The type specimen of the Cape lion was described as very large with black-edged ears and a black mane extending beyond the shoulders and under the belly. Skulls of two lion specimen in the British Natural History Museum from the Orange River basin were described as a little shorter in the occipital regions than other lions in South Africa and with a tendency to develop the second lower premolar. American zoologist Edmund Heller described the Cape lion's skull as longer than those of equatorial lions, by at least on average, despite being comparatively narrow. He considered the Cape lion to have been 'distinctly' bigger than other lions in Africa.
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A passive TPA solidarizes the two molars or the two posterior segments, thus preventing any individual independent movement, as for example molar rotation or tipping due to alignment wires, loops or cantilevers, and this is a kind of anchorage source, however, cannot prevent the movement of the 2 molars as a group, as in the case of premolar space closure. TPA is also used to prevent buccal tipping of the molars when a Burstone-type Segmental Arch mechanics are being used. In a case of open bite, TPA can be used to maintain the molar position when TADs are being used to intrude the upper molars to close the open bite.
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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.
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Side view of KNM WT 17000 Typical of Paranthropus, KNM WT 17000 is heavily built, and the palate and base of the skull are about the same size as the P. boisei holotype OH 5. The brain volume of KNM WT 17000 was estimated to have been , which is smaller than that of other Paranthropus. The combination of a tall face, thick palate, and small braincase caused a highly defined sagittal crest on the midline of the skull. The only complete tooth crown of the specimen is the right third premolar, whose dimensions are well above the range of variation for P. robustus and on the upper end for P. boisei.
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The skeleton of apatemyids was rather slim, and their skull was large in comparison. Other information on skull morphology has been limited due to the skulls of the few complete skeletons of the Apatemyidae being crushed. Significant postcranial adaptations include the elongated second and third digits and elongated and gracile tail. Apatemyids are also characterized by various dental features including a large and procumbent first lower incisor, a vertically oriented first upper incisor, an elongated and blade-like second lower premolar, small and narrow upper and lower cheek teeth, and the presence of an additional antero-buccal cusp and a reduced paraconid on the lower molars.
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Like other members of its genus, B. secundus had a bulging forehead and powerful jaws; it was considered to be probably a scavenger by paleontologists in the past. Its crushing premolar teeth and strong jaw muscles would have been used to crack open bone, much like the hyena of the Old World. However, B. secundus fossils are so abundant and geographically widespread that some paleontologists now argue that it must have been the dominant carnivore of its time, and thus an active predator because carrion feeding alone could not have sustained such a large population.Wang, Xiaoming; and Tedford, Richard H. Dogs: Their Fossil Relatives and Evolutionary History.
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X-ray film reveals a poor crown-to-root ratio for tooth #21 (right), the lower left first premolar. The tooth exhibits 50% bone loss, adding roughly 5-7 mm to the clinical crown of what is actually anatomical root. The fulcrum, existing somewhere immediately apical to the height of the bone, does not allow for any adjacent bone to avoid compression or tension, resulting in virtually complete widening of the PDL and a grim prognosis, due to secondary occlusal trauma. Crown-to-root-ratio is the ratio of the length of the part of a tooth that appears above the alveolar bone versus what lies below it.
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Although the height of the alveolus cannot be determined because the lower side is broken away, the incisor must have been quite deep. When it was discovered that Sudamerica had four molariform teeth and no bladelike premolar in its lower jaw, Pascual, Kielan-Jaworowska, and colleagues removed MACN Pv-RN 975 from Ferugliotherium, which they expected to have the same dental formula as its fellow gondwanathere Sudamerica, and identified it as an indeterminate multituberculate instead. Pascual and colleagues argued that molariform teeth as seen in Sudamerica could not have evolved from the bladelike p4 of Ferugliotherium, and that it was unlikely that additional molars had been added in Sudamerica.
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Two prominent ridges descend from each serration towards the front down the sides of the tooth. No roots are preserved, but the rounded surface of the lower side of the tooth suggests they may have been resorbed, which would indicate that the tooth is deciduous. Krause and colleagues suggested that the tooth may have been the frontmost premolar, whether deciduous or permanent. However, Kielan-Jaworowska and Bonaparte wrote that this tooth does not match the partial jaw MACN Pv-RN 975, which has no alveoli in front of p4, and Pascual and colleagues agreed in 1999 that the tooth probably does not belong to Ferugliotherium.
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Pelycodus is placed within adapiforms because of its annular ectotympanic, small eyes, non- elongated tarsus and numerous premolar and molar crests and within Notharctinae because of its four premolars, unfused mandible, a hypocone derived from the postprotocingulum and a lacrimal bone within the orbit. There is, however, a great deal of individual variation in the dentition of Pelycodus, which has made it hard to differentiate between Pelycodus and Cantius species. Distinguishing features of the Cantius/Pelycodus clade are the comparatively smaller hypocones and mesostyles. The distinguishing features of Pelycodus from Cantius are its anteroposteriorly compressed trigonid, its small paraconid on M2 and lack of hypoconulid on M1-2.
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They are much less common in the mandible (lower jaw) than the maxilla (upper jaw) although mandibular wolf teeth are found very occasionally. They do not have any deciduous precursors but they may themselves be deciduous as it is believed that they are often shed when the deciduous 2nd premolar is shed at around two and a half years of age. They may also be knocked out by the bit if particularly loose and can certainly be extracted accidentally, either partially or whole, when routine equine dentistry is performed. In size they are extremely variable from being small pegs only 3 mm in diameter to having roots up to 2 cm long.
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If Chororapithecus is not a gorillin, it may be a stem hominine or not a hominine at all. The teeth were originally dated to 10.5–10 million years ago (mya), and the discoverers then concluded that the gorilla–human LCA existed about 12 mya, but they were re- dated to about 8 mya. If Chororapithecus was indeed a stem gorilla, the latter date is more consistent with the timing of 8 mya for the LCA according to molecular data. Based on the revised date and similarly large premolar size, the 10 million year old Kenyan Nakalipithecus has been proposed to have been the ancestor to Chororapithecus, which would move the LCA to 10 mya if correct.
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This latter view has gained increasing support with the reclassification of Algeripithecus (once considered a basal simian) as a closely related azibiid. Additional fossil teeth and the maxilla (upper jaw) of both genera discovered between 2003 and 2009 helped demonstrate their relationship. Based on the same fossil finds, Tabelia—which was also considered to be one of the oldest known simians along with Algeripithecus—is also now considered to be a synonym of Azibius. Also, the third and fourth lower premolars (P3 and P4) distinguish azibiids from carpolestids, while the upper fourth premolar (P4) matches what was thought to be the second upper molar (M2) of Dralestes hammadaensis, another suspected plesiadapiform or genus of azibiid.
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Skull cast of Didelphodon in the Rocky Mountain Dinosaur Resource Center in Woodland Park, CO; collected in Harding County, SD. Although perhaps little larger than a Virginia opossum, with a maximum skull length of and a weight of , Didelphodon was a large mammal by Mesozoic standards. The teeth have specialized bladelike cusps and carnassial notches, indicating that the animal was a predator; the jaws are short and massive and bear enormous, bulbous premolar teeth which appear to have been used for crushing. Analyses of a near-complete skull referred to Didelphodon show that it had an unusually high bite force quotient (i.e. bite force relative to body size) among Mesozoic mammals, suggesting a durophagous diet.
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Furthermore, there were deciduous teeth remains or milk molar, premolar, canine and incisive, which appear to approximately correspond to a 1 to 2 years old child. Unfortunately the conservation state of the long bones did not permit obtaining biometric data to infer about the height of the adult individual. Inside two small vases were found, one oblong shaped, flat base and wide mouth (8 cm) short-necked measuring 8 x 11 cm in height and width, Sacasa Striated ceramic type. The second corresponds to a small vessel with socket base, short neck; red slip probably associated with the red Rivas ceramic, measured 9 x 10 cm, height and width, and the mouth diameter is 5.2 cm.
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Ocepeia was first described and named in 2001 by Gheerbrandt and Dr. Jean Sudre (University of Montpellier) based on two lower jaw fragments assigned to the new species O. daouiensis: one (designated CPSGM-MA1), bearing a premolar and first molar, is the holotype for the species. Additional material assigned to O. daouiensis was described in 2010, including a near-complete left lower jaw bone and additional dental fragments. In 2014, new specimens of O. daouiensis were described including a partial skull, upper jaw, and additional teeth, allowing for a complete reconstruction of what the intact skull looked like. The diversity of specimens, combined with CT scans of the partial skull, allowed for a much more detailed and comprehensive description.
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Premolar tooth with amalgam filling This discussion of the dental amalgam controversy outlines the debate over whether dental amalgam (the mercury alloy in dental fillings) should be used. Supporters claim that it is safe, effective and long-lasting while critics argue that claims have been made since the 1840s that amalgam is unsafe because it may cause mercury poisoning and other toxicity. Supporters of amalgam fillings point out that it is safe, durable, relatively inexpensive, and easy to use. On average, amalgam lasts twice as long as resin composites, takes less time to place, is tolerant of saliva or blood contamination during placement (unlike composites), and is often about 20-30% less expensive.
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Galerix kostakii is a fossil erinaceid mammal from the early Miocene of Greece. It is known from the site of Karydia, assigned to the biostratigraphical zone MN 4; similar fossils have been found at an approximately contemporary Czech site and a slightly younger Greek site. With characters like the presence of a hypocone (fourth cusp) on the upper third premolar, the presence of a connection between the protocone and metaconule cusps on the second upper molar in only a few specimens, this species is intermediate between the slightly older Galerix symeonidisi and the slightly younger Parasorex pristinus. It may form part of the lineage leading from the genus Galerix to the younger genus Parasorex.
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In 1993, Krause described an unworn mf1 of Ferugliotherium and confirmed that Vucetichia was based on worn specimens of Ferugliotherium and therefore a synonym of the latter. In the same year, he and Bonaparte argued once again that Ferugliotherium, Gondwanatherium, and Sudamerica formed a closely related group of multituberculates, which they called the superfamily Gondwanatherioidea. Kielan-Jaworowska and Bonaparte described a lower jaw fragment with a multituberculate-like lower fourth premolar (p4) from Los Alamitos in 1996 and tentatively identified it as Ferugliotherium. On the basis of the morphological features of the jaw fragment, they argued that gondwanatherians were not closely related to any other multituberculate group, and consequently placed them in a suborder of their own, Gondwanatheria.
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Notice the massive blade-like lower premolar. Unlike rodents and similar therians, multituberculates had a palinal jaw stroke (front-to-back), instead of a propalinal (back-to-front) or transverse (side-to-side) one; as a consequence, their jaw musculature and cusp orientation is radically different. Palinal jaw strokes are almost entirely absent in modern mammals (with the possible exception of the dugongJ. M. Lanyon & G. D. Sanson, Degenerate dentition of the dugong (Dugong dugon), or why a grazer does not need teeth: morphology, occlusion and wear of mouthparts, Received 26 May 2004; accepted 24 April 2005), but are also present in haramiyidans, argyrolagoideans and tritylodontids, the former historically united with multituberculates on that basis.
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Curve of Spee In anatomy, the Curve of Spee (called also von Spee's curve or Spee's curvature) is defined as the curvature of the mandibular occlusal plane beginning at the premolar and following the buccal cusps of the posterior teeth, continuing to the terminal molar. According to another definition the curve of Spee is an anatomic curvature of the occlusal alignment of the teeth, beginning at the tip of the lower incisor, following the buccal cusps of the natural premolars and molars and continuing to the anterior border of the ramus. It is named for the German embryologist Ferdinand Graf von Spee (1855–1937), who was first to describe the anatomic relations of human teeth in the sagittal plane.
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Onychonycteridae is an extinct family of bats known only from the early Eocene of Europe and North America. The type species, Onychonycteris finneyi, was described in 2008 from two nearly complete skeletons found in the Green River Formation of southwestern Wyoming. Since that time a number of previously described fossil bat species have been assigned to Onychonycteridae, as well as another more recently discovered species Most species belonging to Onychonycteridae are known only from isolated teeth and jaw fragments, however, they can be recognized by their relatively square-shaped upper molars, simple lower fourth premolar, and primitive, necromantodont lower molars. Onychonycteris finneyi exhibits additional primitive features of its skeleton, including claws on all five fingers and a simple cochlea that suggests it was incapable of echolocation.
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The mandibular first molar or six-year molar is the tooth located distally (away from the midline of the face) from both the mandibular second premolars of the mouth but mesial (toward the midline of the face) from both mandibular second molars. It is located on the mandibular (lower) arch of the mouth, and generally opposes the maxillary (upper) first molars and the maxillary 2nd premolar in normal class I occlusion. The function of this molar is similar to that of all molars in regard to grinding being the principal action during mastication, commonly known as chewing. There are usually five well-developed cusps on mandibular first molars: two on the buccal (side nearest the cheek), two lingual (side nearest the tongue), and one distal.
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Through morphometric examination of teeth, researchers concluded that the unknown species of pig was likely domesticated due to its larger size than the Philippine warty pig and its similarity to the domesticated species Sus scrofa. A carbon-14 date on a premolar of the unknown species dates domesticated pigs at ca. 2500-2200 cal BC. Faunal remains of predominantly wild pig were found at the Nagsabaran site, indicating that hunting was the primary subsistence strategy during the Neolithic and Iron Age and pigs were not domesticated for the sole purpose of subsistence. In present-day villages located in Luzon and Palawan, domesticated pigs (Sus scrofa) are only eaten for ceremonial purposes, while wild pigs (Sus philippensis) are never used for rituals.
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In fact, pliopithecoids are more similar to New World monkeys in some aspects of their dentition, including narrow lower incisors (mesiodistally waisted towards the base of the crown). Many species have what is often referred to as a 'pliopithecine triangle', a subtle set of ridges defining a small triangular shaped pit between the protocone and hypocone of the lower molars, but even this trait is variable. Instead, the most defining dental trait present in all pliopithecoids is a tall crowned lower third premolar, which is relatively triangular in outline with a comparatively short, vertically oriented mesiobucal face. The crania of P. vindobonesis, Laccopithecus robustus, Pliopithecus zhanxiangi, and Anapithecus hernyaki demonstrate that pliopithecoids had relatively large and globular braincases with a projecting snout.
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Teeth of a koala, from left to right: molars, premolars (dark), diastema, canines, incisors The koala has several adaptations for its eucalypt diet, which is of low nutritive value, of high toxicity, and high in dietary fibre. The animal's dentition consists of the incisors and cheek teeth (a single premolar and four molars on each jaw), which are separated by a large gap (a characteristic feature of herbivorous mammals). The incisors are used for grasping leaves, which are then passed to the premolars to be snipped at the petiole before being passed to the highly cusped molars, where they are shredded into small pieces. Koalas may also store food in their cheek pouches before it is ready to be chewed.
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Overall, the fossa has features in common with three different carnivoran families, leading researchers to place it and other members of Eupleridae alternatively in Herpestidae, Viverridae, and Felidae. Felid features are primarily those associated with eating and digestion, including tooth shape and facial portions of the skull, the tongue, and the digestive tract, typical of its exclusively carnivorous diet. The remainder of the skull most closely resembles skulls of genus Viverra, while the general body structure is most similar to that of various members of Herpestidae. The permanent dentition is (three incisors, one canine, three or four premolars, and one molar on each side of both the upper and lower jaws), with the deciduous formula being similar but lacking the fourth premolar and the molar.
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As one of two described species of Priscileo, it is estimated to have been around two thirds the size of Priscileo pitikantensis; the body mass of L. roskellyae is calculated as . The upper dental formula of this marsupial was I1–3 C1 P1–13 M 1–4. The premolar P3 is similar in form to the larger tooth in species of Wakaleo, the mid-sized thylacoleonids that also existed at Riversleigh and seemed to occupied different ecological niches in the same time period. The comparative bite force of the species, along with the larger Thylacoleo carnifex, is estimated to have been the greatest of any known mammal and strongly supports the conception of predators that killed animals larger than itself.
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New York: Columbia University Press, 2008. p15 Hyaenodontids, like all creodonts, lacked post-carnassial crushing molar teeth, such as those found in many carnivoran families, especially the Canidae and Ursidae, and thus lacked dental versatility for processing any foods other than meat.Wang, Xiaoming; and Tedford, Richard H. Dogs: Their Fossil Relatives and Evolutionary History. New York: Columbia University Press, 2008. p15-7 Hyaenodontids are very unusual in regards to their tooth replacement. Studies on Hyaenodon show that juveniles took 3–4 years in the last stage of tooth eruption, implying a very long adolescent phase. In North American forms, the first upper premolar erupts before the first upper molar, while European forms show an earlier eruption of the first upper molar.
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Yubaatar had a unique feature among multituberculates in that its last upper premolar was replaced. The holotype specimen had a palaeopathology unique among known Mesozoic mammal, a severely broken right tibia bone, which was probably damaged in an accident, but had healed. Yubaatar was found to be basal to the clade Taeniolabidoidea, which consists of North American and Asian multituberculates; this indicates there was a faunal interchange between Asia and North America before the Cretaceous–Paleogene transition. The morphology of Yubaatar indicates that diversity in the complexity of the teeth of mutituberculates, relating to their diets, increased with the number of genera and difference in body size, and that there wa sa shift in adaptations towards increased herbivory in the group across the Cretaceous–Paleogene boundary.
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23–24 In a well-preserved mandible, the length from the alveolus for the first incisor to the end of m3 is 8.80 mm and the depth of the mandible at m1 is 1.50 mm. Miniopterus zapfei can be identified as a Miniopterus on the basis of the possession of three lower premolars (designated p2, p3, and p4, because the original first premolar has been lost); a two-rooted p3; and the nyctalodont molars, with the posterolophid (a crest at the back of the molar) behind the entoconid cusp. M. zapfei is about 30% larger than M. fossilis and has a more slender p4. Compared to living Miniopterus, the cingulum (shelf) that surrounds the P4 is less well-developed and the parastyle crest is weaker.
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When there is a case of hypodontia of the permanent premolar teeth, the primary molar teeth would often remain in the mouth beyond the time they are meant to be lost. Therefore, with a presence of healthy primary teeth in the absence of a permanent successor, retaining the primary teeth can be a feasible management of hypodontia. The primary molars present also functions as a space maintainer, prevent alveolar bone resorption and delays future prosthodontic space replacement by acting as a semi permanent solution going into adulthood Previous studies also shown a good prognosis of retained primary molars going into adulthood. However, leaving the primary teeth in place may run the risk of tooth infraocclusion where the occlusal surface is below that of adjacent teeth.
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Orthodontic space closure is a way of using orthodontics in order to close spaces in the mouth where the teeth are missing. The ideal age for definitive orthodontic treatment is early adolescence but it is important to consider the patient’s age, severity of hypodontia, patient expectations and their commitment to treatment. It can be an option for hypodontia management in the case of missing maxillary lateral incisors through the reshaping, and mesial re- positioning of the adjacent canine. This management is indicated in hypodontia cases of Class I molar relationship with severe crowding in the mandibular anterior region where the extraction of lower premolar leads to a predictable outcome, and Class II molar relationship in the absence of crowding and protrusion of the mandibular anterior dentition.
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Tribosphenid mammals were originally grouped on the basis of triangular or V-shaped (tribosphenic) molars. Since then, other unrelated mammal groups have been found to have tribosphenic molars, such as the australosphenidans (a group that includes the still extant monotremes), suggesting that as a synapomorphy this is fundamentally useless as it evolved multiple times among mammals. However, a clade between the aforementioned groups, the "true Tribosphenida" or Boreosphenida, is still identifiable, united by characteristics such as the lack of a mesial cingulid and of a triangulated trigonid on the last premolar. They are also united by postcranial features such as the presence of a modern ear (though this too has evolved independently in many other groups, like monotremes), modern shoulder blades, and several features of the hindlimb.
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Boreosphenida (from boreas, "northern wind" and sphen, "wedge") were early mammals that originated in the Northern Hemisphere and had tribosphenic molars (three-cusped cheek teeth). In boreosphenidans, the mandibular angle is placed posteriorly and the primitive postdentary trough (hole in the mandible) is absent (in contrast to Kuehneotheriidae, Eupantotheria, and Australosphenida.) They share the tribosphenic molars with the Australosphenida but differ from them by having cingulid cuspules but lacking a continuous mesial cingulid. Boreosphenidans also lack the triangulated trigonid on the last premolar found in Early Cretaceous mammals. They differ from Shuotherium (a monotreme- relative) in having the talonid placed posterior to the trigonid (like in modern tribosphenic mammals) in the lower molars, but upper molars similar to those of Shuotherium.
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The primitive Parasorex species Parasorex pristinus is about as large as G. kostakii, but its molars are narrower, the first lower premolar (p4) is smaller, and the metacone cusp on M2 has a straight anterior arm. Furthermore, Galerix kostakii lacks the paralophid on p4, a crest that connects the paraconid and protoconid cusps. Galerix kostakii shares some of the features present in Parasorex and Schizogalerix, both derived descendants of Galerix, including the presence of a hypocone on P3, a partitioned posterior cingulum on m1 and m2, and the absence of the protocone-metaconule connection in most M1 and M2. However, it also retains primitive, Galerix-like features, including the condition of p4 and the presence of a protocone-metaconule connection in some specimens.
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However, E. scansoria is not a true placental mammal as it lacks some features that are specific to placentals. These include the presence of a malleolus at the bottom of the fibula, the smaller of the two shin bones, a complete mortise and tenon upper ankle joint, where the rearmost bones of the foot fit into a socket formed by the ends of the tibia and fibula, and an atypical ancestral eutherian dental formula of . Eomaia had five upper and four lower incisors (much more typical for metatherians) and five premolars to three molars. Placental mammals have only up to three incisors on each top and bottom and four premolars to three molars, but the premolar/molar proportion is similar to placentals.
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In 1995, two specimens were recovered from Koro Toro, Bahr el Gazel, Chad: KT12/H1 or "Abel" (a jawbone preserving the premolars, canines, and the right second incisor) and KT12/H2 (an isolated first upper premolar). They were discovered by the Franco-Chadian Paleoanthropological Mission, and reported by French palaeontologist Michel Brunet, French geographer Alain Beauvilain, French anthropologist Yves Coppens, French palaeontologist Emile Heintz, Chadian geochemist engineer Aladji Hamit Elimi Ali Moutaye, and British palaeoanthropologist David Pilbeam. Based on the wildlife assemblage, the remains were roughly dated to the middle to late Pliocene 3.5–3 million years ago. This caused the describers to preliminarily assign the remains to Australopithecus afarensis, which inhabited Ethiopia during that time period, barring more detailed anatomical comparisons.
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In 2004 and 2007, Kielan-Jaworowska and colleagues aligned the dentary with the multituberculate suborder "Plagiaulacida" because the p4 is rectangular in labial view, not curved as in the suborder Cimolodonta. This feature was also used to distinguish MACN Pv-RN 975 from the single p4 assigned to Argentodites, which was tentatively placed in Cimolodonta. Gurovich, Guillermo Rougier, and colleagues, on the other hand, maintain that the dentary is referable to Ferugliotherium and that the p4s of Argentodites and MACN Pv-RN 975 are very similar. The alveolus of MACN Pv-RN 975 fits the lower incisors attributed to Ferugliotherium in size and the blade-like premolar is of the size expected for an animal with molariforms the size of Ferugliotherium teeth.
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The appearance of this animal was vaguely similar to that of a particularly robust, large felid, but the skull resembles that of a canid or an ursid, like that of many amphicyonids. Unlike most other amphicyonids, Magericyon had teeth associated with those of a hypercarnivore, with laterally flattened canines, the third premolar having a single root, the absence of second premolars and a metaconid on its lower molars, with a reduction in the second upper molar. The scapula and the front leg showed primitive features such as an acromion in the shoulder with a reduced caudoventral projection and post scapular pit.Peigné, S., Salesa, M. J., Antón, M. & Morales, J., 2008: A new amphicyonine (Carnivora: Amphicyonidae) from the upper Miocene of Batallones-1, Madrid, Spain.
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Microleo attenboroughi is a very small species of the Thylacoleonidae family from the Early Miocene of Australia, living in the wet forest that dominated Riversleigh about 18 million years ago. The genus Microleo is currently known from a broken palate, two pieces of jaw, containing some teeth and roots that correspond to those found in other species of thylacoleonids. The shape and structure of the blade-like P3 tooth, a premolar, distinguished the species as a new genus. It was found in Early Miocene-aged deposits of the Riversleigh fossil site in Queensland, regarded as one of the most significant palaeontological sites yet discovered, and named for the naturalist David Attenborough in appreciation of his support for its heritage listing.
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Simpson (1967) described Propotto on the basis of mandibles from Early Miocene deposits in Kenya that he regarded as constituting an extinct relative of the extant potto, hence the genus meaning "before Potto".Simpson, G. G. The tertiary lorisiform primates of Africa. Bull. Mus. Comp. Zool. 136, 39–62 (1967). However, the lorisid classification of Propotto was questioned by Walker (1969), who argued that it represented a fruit bat of the family Pteropodidae, noting that the second premolar was smaller than those of lorises and that the mandibular corpus was also unlike those of lorisiforms in deepening anteriorly and having a deep masseteric fossa (Simpson accepted Walker's refutation of the lorisid placement of Propotto).Walker, A. True affinities of Propotto leakeyi Simpson 1967. Nature 223, 647–648 (1969).
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The smallest and most ancient species of Thylacoleo, a genus of three species referred to as "marsupial lions" for the resemblance in form and habits of African lions and distantly related to the modern Thylacinus cynocephalus. They are the earliest species of the genus, appearing in records dating to the Pliocene epoch, and existed at the same time as the larger Thylacoleo crassidentatus. Unlike other of the family, such as well preserved Thylacinus carfinex fossil and subfossil material, T. hilli is represented by a few fragmentary fossil specimens. The possibility that the small premolar of the species may be a deciduous tooth of another, which are sometimes lost or reabsorbed in some genera of Vombatiformes, was excluded by evidence of wear and lack of this feature appearing in other thylacinid species.
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Australopithecus deyiremeda was first proposed in 2015 by Ethiopian palaeoanthropologist Yohannes Haile- Selassie and colleagues based on jawbone fossils from the Burtele and Waytaleyta areas of Woranso–Mille, Afar Region, Ethiopia. The holotype specimen, a young adult left maxilla with all teeth except the first incisor and third molar BRT-VP-3/1, was discovered on 4 March 2011 by local Mohammed Barao. The paratype specimens are a complete adult body of the mandible with all incisors BRT-VP-3/14, and an adult right toothless jawbone WYT-VP-2/10, which were discovered by Ethiopian fossil hunter Ato Alemayehu Asfaw . A right maxilla fragment with the fourth premolar BRT-VP-3/37 was found east of BRT- VP-3/14, and it is unclear if these belonged to the same individual.
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The "Moscow mandible", holotype of E. sibiricum Elasmotherium was first described in 1809 by German/Russian palaeontologist Gotthelf Fischer von Waldheim based on a left lower jaw, four molars, and the tooth root of the third premolar, which was gifted to Moscow University by princess Ekaterina Dashkova in 1807. He first announced it at an 1808 presentation before the Moscow Society of Naturalists.. The genus name derives from Ancient Greek elasmos "laminated" and therion "beast" in reference to the laminated folding of the tooth enamel; and the species name sibericus is probably a reference to the predominantly Siberian origin of princess Dashkova's collection. However, the specimen's exact origins are unknown. In 1877, German naturalist Johann Friedrich von Brandt placed it into the newly erected subfamily Elasmotheriinae, separate from modern rhinos.
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Characteristics of the premolar suggest that it belongs with the Echimyidae, but characteristics of the incisor enamel suggest that it belongs in the Erethizontidae. Patterson and Pascual (1968), Patterson and Wood (1982), Woods (1982, 1984, 1993) Patton and Reig (1989), Nowak (1999), and Carvalho (2000) support the inclusion of this animal in Echimyidae whereas Martin (1994), McKenna and Bell (1997), Carvalho and Salles (2004), and Woods and Kilpatrick (2005) argue that it belongs in Erethizontidae. Emmons (2005) mentions the family Chaetomyidae without much further comment except to exclude it from Echimyidae. A molecular phylogeny based on the mitochondrial gene coding for cytochrome b combined to karyological evidence actually suggests that Chaetomys is more closely related to the Erethizontidae than to the Echimyidae, although it branches as the sister group to the rest of the Erethizontidae.
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Fossils from the genus Lufengpithecus from the late Miocene is crucial in understanding hominoid evolution in Asia. The fossil being studied may be a member of the Homininae and a study wants to show an estimated age of molars in Lufengpithecus lufengensis at time of death. The results of the paper will help understand “Life History” in Miocene and Plio-Pleistocene hominids and great apes and humans. The author uses fossil PA868 as baseline and the fossil is thought to be a juvenile. They use the right mandibular of the fossil which has right four premolar and permanent first molar (M1)and also has five right permanent tooth crown germs which are I1, I2, C, P3, and P4 and the author concludes that PA868 was most likely a female.
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This species is based in the holotype MPEF PV 7735, a fragment of jawbone with molar and premolar teeth associated and a partial canine associated, in addition to several additional specimens that include isolated teeth and other fragments of jaws. From these remains it was established that Maddenia was a small astrapothere, near of 50% smaller than Astraponotus. Its molar were high, with complex crowns and with canines moderately developed, characteristics of the advanced astrapotheres of big size of the Oligocene and the Miocene (like Astrapotherium and Granastrapotherium), which suggests that it must to occupy a habitat differentiated regarding other forms of big size, and that by its anatomical characteristics constitutes an intermediate form between the primitive forms like Albertogaudrya and the astrapotherids like Parastrapotherium, with which conform sister taxa to the two subfamilies of the family Astrapotheriidae, Astrapotheriinae and Uruguaytheriinae.
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Interesting whale fossils were also discovered and described from Michigan around this time. In 1927 excavations for a new schoolhouse in Oscoda turned up a Late Pleistocene fossil rib that may have belonged to a bowhead whale of the genus Balaena. The specimen is now catalogued as UMMP 11008. 1930 saw Hussey publish the first scientific paper on the Michiganian whale fossils curated by the University of Michigan Museum of Paleontology. The fourth decade of the twentieth century was kicked off by the 1940 announcement by MacAlpin that a total of 117 American mastodon specimens had been discovered in Michigan. Later in the decade, a third lower premolar from a Pleistocene elk was discovered in Berrien County in October, 1949. Restoration of a Columbian or "Jefferson" mammoth The 1950s saw paleontological attention return to Michigan's whale fossils.
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Roman Croitor has suggested closer affinities to Eucladoceros for M. savini and related species. The origin of M. giganteus remains unclear, and appears to lie outside Western Europe. Jan van der Made has suggested that remains of an indeterminate Megaloceros species from the late Early Pleistocene (~1.2 Ma) of Libakos in Greece are closer to M. giganteus than the M. novocarthaginiensis-matritensis lineage due to the shared molarisation of the lower fourth premolar (P4). Croitor has suggested that M. giganteus is closely related to what was originally described as Dama clactoniana mugharensis (which he proposes be named Megaloceros mugharensis) from the Middle Pleistocene of Tabun Cave in Israel, due to similarities in the antlers, molars and premolars. The earliest possible records of M. giganteus comes from Homersfield, Norfolk, thought to be about 450,000 years ago—though the dating is uncertain.
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Simple snaffle bit fitted to a horse, behind the incisors, but in front of the premolars If a bit is fitted to a horse, along with a bridle, the normally metal bar of the bit lies in the interdental space between the incisors (or canines, where present) and premolars. If the bridle is adjusted so that the bit rests too low, or too high, it may push against the teeth and cause discomfort. Sometimes, a "bit seat" is filed in the first premolar, where the surface is rounded so that the flesh of the cheek is not pushed into the sharp edge of the tooth, making riding more comfortable for the horse, although the practice is controversial.Paul McGreevy, Janne Winther Christensen, Uta König von Borstel, and Andrew McLean, Equitation Science (London: John Wiley & Sons, 2018), 224-25.
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Meng and Wyss, 1994, p. 201 The loss of the second upper premolar (P2) has also been considered as synapomorphic for Simplicidentata, but the primitive simplicidentate Sinomylus does have a P2.McKenna and Meng, 2001, p. 565 This sense of Simplicidentata was introduced by Chuankui Li and colleagues in 1987, who ranked Simplicidentata as a superorder including Rodentia and the extinct Mixodontia, contrasted with the superorder Duplicidentata (including Lagomorpha and the extinct Mimotonida).Meng and Wyss, 1994, p. 199 In their 1997 book Classification of Mammals, Malcolm C. McKenna and Susan K. Bell ranked Simplicidentata as a mirorder within the grandorder Anagalida (also including lagomorphs, macroscelideans, and some additional extinct groups). Within Simplicidentata, they recognized the orders Mixodontia (including only the extinct family Eurymylidae from the Paleocene and Eocene of Asia) and Rodentia.McKenna and Bell, 1997, p.
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A marsupial with highly specialised dentition, an enlarged premolar with a flattened profile used to hammer open the shells of snails found in its wet forested environment. This tooth was compared by the authors to a genus of skinks, Cyclodomorphus, and concluded this represented evolutionary convergence with the modern skinks that have similar adaptation to their diet of snails; the authors gave a generalised description of this unusual animal as a "marsupial-skink". A leading author on the research and description of the species, professor Michael Archer, said of the type species, "Malleodectes mirabilis was a bizarre mammal, as strange in its own way as a koala or kangaroo …,". Fossil material associated with genus had been collected by workers at Riversleigh in the years leading to the crucial discovery of a juvenile jaw containing unerupted adult teeth.
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Interior of Callao Cave, Luzon, the Philippines The first remains were discovered in 2007 in Callao Cave in Northern Luzon, the Philippines. In 2010, French anthropologist Florent Détroit and Filipino archaeologist Armand Mijares and colleagues identified them as belonging to modern humans. In 2019, after the discovery of 12 new specimens and based on the apparent presence of both modern-humanlike and primitive Australopithecus-like features, they reassigned the remains (and other hominin findings from the cave) to a new species, Homo luzonensis, the species name deriving from the name of the island. The holotype, CCH6, comprises the upper right premolars and molars. The paratypes are: CCH1, a right third metatarsal bone of the foot; CCH2 and CCH5, two phalanges of the fingers; CCH3 and CCH4, two phalanges of the foot; CCH4, a left premolar; and CCH9, a right third molar.
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The mandibular incisive canal is a bony canal within the anterior mandible that runs bilaterally from the mental foramina usually to the region of the ipsilateral lateral incisor teeth. After branching into the mental nerve that exits the foramen of the same name, the inferior alveolar nerve continues anteriorly within the mandibular incisive canal as the incisive nerve, providing innervation to the mandibular first premolar, canine and lateral and central incisors.Greenstein, G; Cavallaro, J; Tarnow, D. "Practical Application of Anatomy for the Dental Implant Surgeon," J Perio 2008;79:1833-1846 The mandibular incisive nerve either terminates as nerve endings within the anterior teeth or adjacent bone, or may join nerve endings that enter through the tiny lingual foramen. The incisive canal is typically found within the middle third of the mandible in an apico-coronal dimension, reaching the midline 18% of the time.
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Stereo micrographs showing premolars and molars of the holotype, including an isolated molar (B) The dental formula (the number of teeth of each type in the tooth row of a mammal) of Catopsbaatar was (two incisors, no canines, three premolars and two molars in half of the upper tooth row, and one incisor, no canines, two premolars and two molars in half of the lower). By comparison, the dental formula of humans is . Each tooth in a mammal is designated with a letter and number by position (I for incisor, C for canine, P for premolar, M for molar); the letters are capitalised for the teeth of the upper jaw, but not for those in the lower jaw. The cusp formula shows the arrangement and number of cusps in consecutive rows of a tooth, from the outer to the inner side; each row is separated by a colon.
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Viverrids are the most primitive of all the families of feliform Carnivora and clearly less specialized than the Felidae. In external characteristics, they are distinguished from the Felidae by the longer muzzle and tuft of facial vibrissae between the lower jaw bones, and by the shorter limbs and the five- toed hind foot with the first digit present. The skull differs by the position of the postpalatine foramina on the maxilla, almost always well in advance of the maxillopalatine suture, and usually about the level of the second premolar; and by the distinct external division of the auditory bulla into its two elements either by a definite groove or, when rarely this is obliterated, by the depression of the tympanic bone in front of the swollen entotympanic. The typical dental formula is: , but the number may be reduced, although never to the same extent as in the Felidae.
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This specimen comprises a single premolar and four molars (p3 – m4) from a single right lower jaw and are assigned to B. wyomingensis based on the shape and dimensions of the teeth. The final locality within North America is located in Trans-Pecos, Texas, USA, and contains well documented records of Brachyhyops wyomingensis from the late Duchesnean Porvenir local fauna which is situated above a volcanic ash that is radioisotopically dated to 37.8 ± 0.15 Ma. The fact that there is no stratigraphic overlap between northern and southern Asian Brachyhyops specimens, suggests that Brachyhyops originated in southern Asia during the early and late middle Eocene and continuously dispersed into northern Asia. Long term exposure of the Beringian land bridge during the late Eocene promoted continuous intercontinental dispersal from Asia into North America, resulting in further dispersal and diversification of Brachyhyops across western North America during the late Eocene.
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Reconstruction of an H. floresiensis female The most important and obvious identifying features of H. floresiensis are its small body and small cranial capacity. Brown and Morwood also identified a number of additional, less obvious features that might distinguish LB1 from modern H. sapiens, including the form of the teeth, the absence of a chin, and the lesser angle in the head of the humerus (upper arm bone). Each of these putative distinguishing features has been heavily scrutinized by the scientific community, with different research groups reaching differing conclusions as to whether these features support the original designation of a new species, or whether they identify LB1 as a severely pathological H. sapiens. A 2015 study of the dental morphology of 40 teeth of H. floresiensis compared to 450 teeth of living and extinct human species, states that they had "primitive canine-premolar and advanced molar morphologies," which is unique among hominins.
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The remains of H. miyou were discovered in Patajau, in the Castilletes Formation of La Guajira department, on northern Colombia. The deposits of Castilletes corresponds to the older SALMAs Santacrucian- Colloncuran, 16.7–14.2 million years ago during the early Middle Miocene. The remains the holotype, IGMp 881327, consists on a partial mandible with the left ramus, some of the molars and the canines, the left condylar process, a second upper molar (M2) and the distal portion of the femur. Also were referred to H. miyou the specimens MUN-STRI 34216, a fragmentary skull with portion of the occipitals, palatines, and left upper canine, an upper fourth premolar P4 and the second upper M2, and a fragmentary mandibular symphysis with the base of the lower canines and alveoli for left three incisives (i3, i2, and i1) and the right first incisives (i1 and i2); and MUN-STRI 38073, which consists in a left P4 and upper molar fragments.
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Australopithecus bahrelghazali is an extinct species of australopithecine discovered in 1995 at Koro Toro, Bahr el Gazel, Chad, existing around 3.5 million years ago in the Pliocene. It is the first and only australopithecine known from Central Africa, and demonstrates that this group was widely distributed across Africa as opposed to being restricted to East and southern Africa as previously thought. The validity of A. bahrelghazali has not been widely accepted, in favour of classifying the specimens as A. afarensis, a better known Pliocene australopithecine from East Africa, because of the anatomical similarity and the fact that A. bahrelghazali is known only from 3 partial jawbones and an isolated premolar. The specimens inhabited a lakeside grassland environment with sparse tree cover, possibly similar to the modern Okavango Delta, and similarly predominantly ate C4 savanna foods—such as grasses, sedges, storage organs, or rhizomes—and to a lesser degree also C3 forest foods—such as fruits, flowers, pods, or insects.
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The alveolus (tooth socket) of Catopsbaatar's I3 incisor was formed by the premaxilla, rather than the premaxilla and maxilla (unlike in Tombaatar). The front upper premolars P1 and P3 were only present in juveniles (deciduous), disappearing (with their alveoli) in older individuals. P1 appears to have had two cusps, was single-rooted, and had a cone-like, blunt crown. P3 was single-rooted and smaller than P1. The cusp formula of the P4 premolar was 5−4:1, the central cusp being the largest. The P4 of Catopsbaatar was almost trapezoidal in shape (unlike in Djadochtatherium and Kryptobaatar, where it is crescent-shaped), smaller, and lacking ridges. Catopsbaatar also differed by having only three upper premolars, lacking the P2 (a feature shared with Tombaatar). Other mammals usually evolve the loss of teeth at the beginning or end of a tooth row, not in the middle (as in multituberculates). The cusp formula of the M1 molar was 5−6:5−6:4, with the inner ridge extending about 75 percent of the tooth's length.
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Coon who excavated Bisitun Cave described two hominid remains from the site, a maxilliary upper incisor and a radius shaft fragment, both from a Layer designated F+. These remains were listed but never described fully for the palaeontological community. When they were finally reexamined four decades later, the incisor was found to be of bovine, rather than hominid origin. The radius fragment was found to show Neanderthal affinities, as it is mediolaterally expanded at the interosseus crest. Metrically, it is outside the range of variation of early anatomically modern humans, but in the range of Neanderthals and early Upper Paleolithic humans.Trinkaus, E and F. Biglari (2006) Middle Paleolithic Human Remains from Bisitun Cave, Iran, Paleorient: 32.2: 105- 111 The radius fragment also showed signs of scavenging carnivores or rodents, such as jackal and fox, the remains of which were also found at the site. Wezmeh Child or Wezmeh 1 represented by an isolated unerupted human maxillary right premolar tooth (P3 or possibly P4) of an individual between 6–10 years old.
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Samonds, 2007, p. 39 Hipposideros, the genus to which H. besaoka is assigned, contains the living species Hipposideros commersoni from Madagascar, among many others.Samonds, 2007, p. 45 The specific name besaoka is the Malagasy for "big chin".Samonds, 2007, p. 49 The material of H. besaoka is from locality TW-10 within the cave and is about 10,000 years old or younger.Samonds, 2007, pp. 42, 49 A cladistic analysis using morphological data suggests that H. besaoka is most closely related to the mainland African H. gigas and H. vittatus, previously included in H. commersoni, and somewhat more distantly to H. commersoni itself.Samonds, 2006, p. 183 Samonds also found Hipposideros material in other sites at Anjohibe, but did not assign it to H. besaoka. In Old SE, also at most 10,000 years old,Samonds, 2007, p. 42 a single fourth upper premolar (P4) was found with dimensions different from those seen in both H. commersoni and H. besaoka and lacking a cusp on the front lingual (inner) corner, present in both other species; Samonds assigned this specimen to Hipposideros sp. cf.
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OOKP is a two-stage operation: Stage 1 of the surgery involves five separate procedures: # The eye is opened up and the entire inner surface of the eyelids, corneal surface and all scar tissue is removed # Inner mucosal lining of the cheek is transplanted onto the new surface of the eye # A canine or premolar tooth and part of the adjacent bone and ligaments are removed # A bolt-shaped structure is fashioned from the tooth-bone complex which is fitted with a plastic optical cylinder # The tooth-bone-cylinder complex is implanted into the patient's cheek to grow a new blood supply Stage 2 (about 4 months later) involves two separate procedures: # The cheek mucosal lining over the eye is opened and the inner contents of the eye are removed # The tooth-bone- cylinder complex is removed from the cheek and inserted into the eye, the mucosal cheek lining is replaced over the implant. At the end of the procedure, light can now enter through the plastic cylinder, and the patient is able to see through this cylinder with good vision.
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The dental arches are the two arches (crescent arrangements) of teeth, one on each jaw, that together constitute the dentition. In humans and many other species; the superior (maxillary or upper) dental arch is a little larger than the inferior (mandibular or lower) arch, so that in the normal condition the teeth in the maxilla (upper jaw) slightly overlap those of the mandible (lower jaw) both in front and at the sides. The way that the jaws, and thus the dental arches, approach each other when the mouth closes, which is called the occlusion, determines the occlusal relationship of opposing teeth, and it is subject to malocclusion (such as crossbite) if facial or dental development was imperfect. Because the upper central incisors are wider than the lower ones, the other teeth in the upper arch are arrayed somewhat distally, and the two sets do not quite correspond to each other when the mouth is closed: thus the upper canine tooth rests partly on the lower canine and partly on the lower first premolar, and the cusps of the upper molar teeth lie behind the corresponding cusps of the lower molar teeth.
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Whereas some traits, such as the talonid (crushing heel) of the premolar tooth P4 being reduced, were interpreted as more derived, many of the features exhibited, including the overall morphology and dimensions of the teeth and jaw, were considered primitive. Because a similar mosaic of jaw traits have been found in African fossils referred to H. ergaster, Rosas and De Castro suggested that the jaw best be classified as Homo sp. indet. (aff. ergaster).' Dmanisi Skull 2 (D2282) Gabunia and colleagues described Skulls 1 and 2 in 2000 and noted that though the facial skeleton of Skull 2 was fragmentary, its estimated proportions and reconstructed morphology were very similar to specimens of H. ergaster recovered at Koobi Fora in Kenya and that the dentition in particular was reminiscent in size and morphology to the dentition known from H. ergaster specimens such as KNM-WT 15000 and KNM ER 3733. Gabunia and colleagues noted that although the cranial capacities of the Dmanisi skulls was lower than the average of H. ergaster, the skulls differed from early Homo such as H. habilis and H. rudolfensis in a number of traits that more closely aligned the fossils with H. ergaster.
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Traits differentiating the Dmanisi hominins from early Homo were noted as including the well-developed brow ridge, the lack of cresting (otherwise present in early Homo and in other great apes), large orbits, the premolar teeth in the upper jaw having single roots and the angulation of the cranial vault. Numerous traits were noted as suggesting a close relation to H. ergaster, including the presence and morphology of the brow ridge, the overall proportions of the facial skeleton, the relative narrowness of the skull beyond the face (post-orbital constriction) as well as a comparable height of the cranial vault and the thickness of the cranial vault bones. The same features typically used to distinguish H. ergaster from Asian specimens of H. erectus were found to distinguish the Dmanisi fossils from Asian H. erectus; notably the lower cranial vault and somewhat thinner cranial vault bones in H. erectus and the smaller cranial capacity of the Dmanisi fossils. A handful of features were noted as present in the Dmanisi fossils and Asian H. erectus, but not H. ergaster, such as the presence of a supramastoid crest).
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