LE PEUPLEMENT DE L’ASIE DU SUD-EST PAR HOMO SAPIENS : ANALYSE DE LA VARIABILITE MORPHOLOGIQUE DES MOLAIRES DEFINITIVES HUMAINES

The biological diversity of modern humans in Southeast Asia has long been regarded as resulting of two major migrations waves. Nevertheless, alternative and/or more complex scenarios have also been proposed. Analysis of the morphological variability of osteological and dental archaeological series is a corner stone as they are direct evidence of the main past events that shaped the modern human diversity in the region. The present study is based on a comparative analysis of the crown contour shape of permanent modern human molars with the combined advantages of a large archaeological sampling and the use of methods which allow detecting and quantifying low intraspecific morphological changes (size and shape of human teeth have a high degree of heritabiliy). The sample includes 1537 modern human molars from Mainland and Island Southeast Asia, Australia and Melanesia; 661 are coming from various chrono‐cultural periods spanning from the Upper Pleistocene to the sub‐actual period. Important methodological developments presented in this work circumvent major difficulties due to particular crown features of human molars: (i) development of a new procedure for the normalization (= standardization) of molar crown outlines that allows using elliptic Fourier analysis, (ii) creation of a new method for the determination of the rank of isolated modern human molars that is highly reliable (≤5% of misclassifications). Our results, based on quantified patterns of shape and size diversity, morphological affinities as well as elaboration and test of design matrices modeling main hypotheses for the peopling of Southeast Asia, are congruent with scenarios based on series of migratory processes since the Upper Pleistocene. Sea level variations (especially at the Last Glacial Maximum) and demic diffusion of the “Neolithic” in certain regions are likely to impact significantly on the structure of the biological diversity of modern humans in Southeast Asia. The major outcomes of the present study are congruent with the results of several recent genetic works in the region. In conclusion, Southeast Asia is a key region for future development aiming at understanding the history and diversity of Homo sapiens.