The 81st Annual Meeting of the American Association of Physical Anthropologists (2012)

Discrete dental traits in chimpanzees


Anatomy and Cell Biology, University of Melbourne

Thursday 9:00-9:15, Broadway III/IV Add to calendar

Descriptions of discrete dental traits form a large part of the differential diagnosis of early hominin taxa. In contrast, the patterns of variance and covariance in dental trait expression are poorly documented in close evolutionary relatives, the extant apes. The aim of this study is to document the nature and patterns of discrete dental trait expression in chimpanzees, and test the hypothesis that chimpanzee species and subspecies can be differentiated by dental traits.

Dentitions of 341 chimpanzees were sorted into subspecies (P. t. verus, n=64; P. t. ellioti, n=9; P. t. troglodytes, n=143; P. t. schweinfurthii, n=79) and species (P. paniscus, n=46). Frequency counts were used to document dental trait expression. Chi-square statistics indicate that P. paniscus and P. troglodytes differ significantly in the frequency of occurrence of the median lingual pillar and mesial fovea on incisors, accessory tubercles on upper third premolar and tuberculum sextum on lower second and third molars. The subspecies of P. troglodytes can be differentiated by the frequency of the cingulum on premolars and trigonid crest on molars. Significant differences separate chimpanzee species in mean measure of distance analyses, P. t. verus is highly divergent from P. t. troglodytes and P. t. schweinfurthii, but distances separating P. t. ellioti are not statistically significant. This study furthers our understanding of the systematics of our closest evolutionary relative, while providing a framework for interpreting variability in dental traits in early hominins.

This study was funded by the department of Anatomy and Cell Biology, University of Melbourne, Enhancing Research Performance Grant

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