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

Geometric morphometric analysis of shape variation in the mandible of fossil and extant hominoids


1Department of Biology and MLT, Bronx Community College, 2Evolutionary Anthropology Labs, University of Minnesota, 3Leverhulme Fellow, Durham University, 4Department of Anthropology, University of Toronto

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Mandibular morphology figures prominently in our understanding of human and ape evolution, with many features considered important to taxonomic and phylogenetic hypotheses of hominoid evolution. Nevertheless, 3D geometric morphometric studies have largely neglected the hominoid mandible, and none has investigated variation both within and among fossil and extant hominoids. Here, we present results from a series of morphometric analyses based on large samples of extant hominoid mandibles and several important fossil specimens.

The 3D landmark data we analyzed clearly distinguish between species and even subspecies of extant hominoids. Compared to a recent discriminant analysis based on linear data (Lague et al., 2008), the landmark analyses performed equally well at distinguishing between subspecies of P. troglodytes and performed better in discriminations among subspecies of G. gorilla and Po. pygmaeus, and species of Pan. Interestingly, phenetic relationships among extant genera show similarities between Pan and Pongo and between Symphalangus and Gorilla. Among the fossils, there is substantial variation within the genus Australopithecus. Whereas A. afarensis specimens are most similar to those of Gorilla, the A. africanus mandible is closest to Pan, and particularly to P. paniscus.

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