Bulletins et Mémoires de la Société d’Anthropologie de Paris (Jun 2008)
Diversité taxonomique des Hominidés fossiles en Asie : de nouvelles méthodes pour une vieille question
Abstract
The objectives of this study were to determine whether the fossils discovered in Asia belong to one or several taxa, to identify them and to compare the distances between them to the distances between actual groups and species of anthropoids. For this purpose, we have used new geometric morphometric methods. Twenty three dimensional landmarks were digitized on 110 skulls: 18 fossils from Asia dated between 1,150,000 years and 6,000 BC, 31 modern Homo sapiens, 31 chimpanzees and 30 gorillas. Landmarks were registered by Generalized Procruste Analysis. We used a logical and objective method with three steps. 1) The taxa variabilities were explored by using several distance indices (variance, Euclidean and Manhattan distances). 2) We have chosen not to arbitrarily group fossils in established taxonomic categories: Principal component analysis (PCA) and hierarchical classification methods (UPGMA and NJ) were applied to identify subgroups for each of the four taxa. Finally, Mahalanobis distances between identified groups and subgroups were calculated and compared between each other. The overall variability was larger for the fossil group than for any of the three actual species, although the difference was statistically significant only for the comparison to the modern H. sapiens. Classification and PCA analysis identified two subgroups within the fossil group: one with an H. sapiens affinity and the other with an H. erectus affinity. The Mahalanobis distances were ordered as follows (decreasing order): gorilla/modern H. sapiens, chimpanzee/modern H. sapiens, chimpanzee/gorilla which was very similar to the distance between modern H. sapiens and H. erectus. This last distance was similar to the one between fossil H. sapiens and H. erectus. Distances between modern and fossil H. sapiens and between subgroups of actual species were similar and less than the preceding ones. We finally concluded that the fossils belong to two different taxa. The first (fossil H. sapiens) belongs to the same taxon as modern H. sapiens and the second, H. erectus, is different.
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