Paper short abstract:

Patterns of shape variations of upper molar teeth from submodern populations are explored and suggest that they might usefully be employed as a proxy to infer population history of Homo sapiens in Southeast Asia.

Paper long abstract:

Peopling of Southeast Asia by Homo sapiens is often regarded as resulting of two major migration waves (i.e. "Two-Layer Hypothesis"). However, most of the published large scale comparative morphological analyses (including osteological or dental series) did not detect evidence for hypothetic Late Pleistocene or Holocene migration wave(s). Rather, the correlation between morphological and geographical distances suggests a predominant role of local evolutionary processes in shaping present-day human biological diversity. Does this mean that Southeast Asia was settled in one major initial wave of migration (followed by local evolutionary processes) or that morphological variations from submodern populations are not a reliable proxy to infer population history? The present study includes a large sample of submodern permanent upper molar teeth from mainland and island Southeast Asia, Australia and Melanesia as well as 661 upper molars from various chrono-cultural periods spanning from the Upper Pleistocene to the Late Holocene. Shape variability and affinities are described by multivariate statistical analyses. The presence of a major Late Holocene wave of migration is tested by a modelling approach. Analyses are first undertaken on our sample of submodern teeth. Then archaeological specimens, considered as a direct evidence of past population events, are included in order to compare the results. While showing geographic structure to some extent, patterns of variations contained in our submodern sample are congruent with a scenario based primarily on population movements. However, the integration of specimens from archaeological contexts brings invaluable information and makes possible to propose more detailed hypotheses.