Ancient teeth and modern humans: additional dental evidence for an African origin of Homo sapiens

Previous work by the first author suggested that, relative to six modern comparative samples, sub-Saharan Africans are least derived dentally from an ancestral hominin state and, hence, may have the greatest time depth of all living world populations. This conclusion, together with other dental evidence, was judged to be supportive of an African origin for modern humans. In the present study, we expand upon this research by using: 1) primary dental data from African Plio-Pleistocene hominins, rather than published trait frequencies, 2) a single morphological scoring system (ASU Dental Anthropology System) with consistent breakpoints, and 3) data from larger, more varied modern comparative samples. The Mean Measure of Divergence was again used to estimate phenetic affinities among modern humans and fossil hominins. Principal Components Analysis was also employed on trait frequencies across samples. Both methods yielded similar results that support and bolster the previous findings. Of 14 modern samples, sub-Saharan Africans again exhibit the closest affinity to the hominins, in their shared prevalence of complex crown and root traits. The fact that the Africans express these plesiomorphic characters, along with evidence of divergence from other modern groups, intra-population heterogeneity, and a world-wide dental cline emanating from the sub-continent, provides more definitive support for an Out-of-Africa origins model. The first author's comparative data were collected through funding by NSF (BNS-9013942), the ASU Research Development Program, and the American Museum of Natural History. The second author's hominin data were collected via funding by an OSU seed grant and the Leakey Foundation.