Molar occlusion and jaw roll in early crown mammals
| Autor: | Thomas Martin, Richard L. Cifelli, Kai R. K. Jäger |
|---|---|
| Jazyk: | angličtina |
| Rok vydání: | 2020 |
| Předmět: |
0106 biological sciences
Molar 010506 paleontology Evolution medicine.medical_treatment Science 010603 evolutionary biology 01 natural sciences Crown (dentistry) Article stomatognathic system Triconodontidae medicine Premolar Animals Biomechanics Eutriconodonta 0105 earth and related environmental sciences Orthodontics Mammals Tooth Crown Multidisciplinary biology Dentition Embrasure Fossils Palaeontology Feeding Behavior biology.organism_classification Biological Evolution Masticatory force medicine.anatomical_structure Medicine |
| Zdroj: | Scientific Reports Scientific Reports, Vol 10, Iss 1, Pp 1-12 (2020) |
| ISSN: | 2045-2322 |
| Popis: | Triconodontidae are considered the first carnivorous crown mammals. A virtual reconstruction of the masticatory cycle in the Late Jurassic Priacodon showed that triconodontid dental function is characterized by precise cutting on elongated crests. The combination of traits linked to both carnivorous diets (e.g. fore-aft cutting edges) and insectivorous diets (transverse crests and lobes) suggests a varied faunivorous diet appropriate to the small body size of most triconodontids. Total length of molar shear decreased with wear, suggesting a dietary shift during ontogeny. Embrasure occlusion is confirmed for P. fruitaensis as indicated by premolar positioning, facet orientation, and collision areas. Embrasure occlusion is considered a general feature of all Eutriconodonta, whereas the previously assumed Morganucodon-like pattern is limited to few early mammaliaforms. Unlike modern carnivores, significant roll of around 10° of the active hemimandible occurred during the power stroke. Roll was likely passive in Triconodontidae in contrast to active roll described for extant therians. The triconodontid molar series was highly uniform and adapted to a precise fit, with self-sharpening lower molar cusps. Whereas the uniformity ensured good cutting capabilities, it likely put the dentition under greater constraints, conserving the highly stereotyped nature of triconodontid molars for 60–85 Ma. |
| Databáze: | OpenAIRE |
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