Analyse phylogénétique des Hominidés de la Sierra de Atapuerca (Sima de los Huesos et Gran Dolina TD-6): l'évidence crânienne

Abstract

Sierra de Atapuerca (Sima de los Huesos and Gran Dolina TD-6) hominids phylogenetic analysis: the cranial evidence. The level TD6 at the Gran Dolina site, Sierra de Atapuerca (Burgos, Spain), has produced the earliest European human remains, dating from the Lower Pleistocene. The Sima de los Huesos site, also in the Sierra de Atapuerca, is currently regarded as the richest Middle Pleistocene site in human fossils. The human fossil record from both sites contains many cranial remains which allow us to study the human evolution along the Lower and the Middle Pleistocene. We have carried out a study of the endocranial volumes of Cranium 4 and Cranium 5, comparing the results obtained using classical measurement techniques with those obtained using tridimensional reconstructions with computer axial tomographies (CAT). The values found using both techniques are virtually identical and endorse the CAT techniques for the studies on fossil internal structures. On the other hand, our phylogenetical analysis shows that the Sima de los Huesos specimens present an assemblage of primitive features together with other traits which strongly relate them with the Neandertal populations. The Gran Dolina human fossils, assigned to Homo antecessor species, present a constellation of cranial features which led us to propose this species as the last common ancestor of Neandertals and modern humans.