human populations, ranging from a near 0% incidence rate among aboriginal tasmanians to near 100% among indigenous mexicans. indrisee commenta prosimian. dental formula disputed. either 2.1.2.32.0.2.3 or 2.1.2.31.1.2.3. proponents of both formulae agree there are 30 teeth and that there are only four teeth in the dental comb. lepilemur0.1.3.32.1.3.3a prosimian. the upper incisors are lost in the adult, but are present in the deciduous dentition. lion3.1.3.13.1.2.1 mole3.1.4.33.1.4.3 mouse1.0.0.31.0.0.3plains pocket mouse (perognathus flavescens) have dental formula of 1.0.1.31.0.1.3. new world monkeyssee commentall new world monkeys have a dentition formula of 2.1.3.32.1.3.3 or 2.1.3.22.1.3.2. pantodonta 3.1.4.33.1.4.3 extinct suborder of early eutherians. pig (deciduous)3.1.4.03.1.4.0 pig (permanent)3.1.4.33.1.4.3 rabbit2.0.3.31.0.2.3 raccoon3.1.4.23.1.4.2 rat1.0.0.31.0.0.3 sheep (deciduous)0.0.3.04.0.3.0 sheep (permanent)0.0.3.33.1.3.3 shrew3.1.3.33.1.3.3 sifakassee commentprosimians. dental formula disputed. either 2.1.2.32.0.2.3 or 2.1.2.31.1.2.3. possess dental comb comprising four teeth. slender lorisslow loris2.1.3.32.1.3.3prosimians. lower incisors and canines form a dental comb; upper anterior dentition is peg-like and short. squirrel1.0.2.31.0.1.3 tarsiers2.1.3.31.1.3.3prosimians. tiger3.1.3.13.1.2.1 vole (field)1.0.0.31.0.0.3 weasel3.1.3.13.1.3.2 dentition use in archaeology dentition, or the study of teeth, is an important area of study for archaeologists, especially those specializing in the study of older remains. dentition affords many advantages over studying the rest of the skeleton itself (osteometry). the structure and arrangement of teeth is constant and, although it is inherited, does not undergo extensive change during environmental change, dietary specializations, or alterations in use patterns. the rest of the skeleton is much more likely to exhibit change because of adaptation. teeth also preserve better than bone, and so the sample of teeth available to archaeologists is much more extensive and therefore more representative. dentition is particularly useful in tracking ancient populations' movements, because there are differences in the shapes of incisors, the number of grooves on molars, presence/absence of wisdom teeth, and extra cusps on particular teeth. these differences can not only be associated with different populations across space, but also change over time so that the study of the characteristics of teeth could say which population one is dealing with, and at what point in that population's history they are. dinosaurs a dinosaur's dentition included all the teeth in its jawbones, which consist of the dentary, maxillary, and in some cases the premaxillary bones. the maxilla is the main bone of the upper jaw. the premaxilla is a smaller bone forming the anterior of the animal's upper jaw. the dentary is the main bone that forms the lower jaw (mandible). the predentary is a smaller bone that forms the anterior end of the lower jaw in ornithischian dinosaurs; it is always edentulous and supported a horny beak. unlike modern lizards, dinosaur teeth grew individually in the sockets of the jawbones, which are known as the alveoli. this thecodont dentition is also present in crocodilians and mammals, but is not found among the non-archosaur reptiles, which instead have acrodont or pleurodont dentition. teeth that were lost were replaced by teeth below the roots in each tooth socket. occlusion refers to the closing of the dinosaur's mouth, where the teeth from the upper and lower parts of the jaw meet. if the occlusion causes teeth from the maxillary or premaxillary bones to cover the teeth of the dentary and predentary, the dinosaur is said to have an overbite, the most common condition in this group. the opposite condition is considered to be an underbite, which is rare in theropod dinosaurs. the majority of dinosaurs had teeth that were similarly shaped throughout their jaws but varied in size. dinosaur tooth shapes included cylindrical, peg-like, teardrop-shaped, leaf-like, diamond-shaped and blade-like. a dinosaur that has a variety of tooth shapes is said to have heterodont dentition. an example of this are dinosaurs of the group heterodontosauridae and the enigmatic early dinosaur, eoraptor. while most dinosaurs had a single row of teeth on each side of their jaws, others had dental batteries where teeth in the cheek region were fused together to form compound teeth. individually these teeth were not suitable for grinding food, but when joined together with other teeth they would form a large surface area for the mechanical digestion of tough plant materials. this type of dental strategy is observed in ornithopod and ceratopsian dinosaurs as well as the duck-billed hadrosaurs, which had more than one hundred teeth in each dental battery. the teeth of carnivorous dinosaurs, called ziphodont, were typically blade-like or cone-shaped, curved, with serrated edges. this dentition was adapted for grasping and cutting through flesh. in some cases, as observed in the railroad-spike-sized teeth of tyrannosaurus rex, the teeth were designed to puncture and crush bone. some dinosaurs had procumbent teeth, which projected forward in the mouth.