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 Pl eistocene. 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 whi ch allow us to study the human evolution along the Lower and the Middle Ple istocene. We have carried out a study of the endocranial volumes of Cranium 4 and Cranium 5, comparing the results obtained using classical measuremen t techniques with those obtained using tridimensional reconstructions with computer axial tomographies (CAT). The values found using both techniques a re virtually identical and endorse the CAT techniques for the studies on fo ssil internal structures. On the other hand, our phylogenetical analysis sh ows that the Sima de los Huesos specimens present an assemblage of primitiv e features together with other traits which strongly relate them with the N eandertal populations. The Gran Dolina human fossils, assigned to Home ante cessor species, present a constellation of cranial features which led us to propose this species as the last common ancestor of Neandertals and modem humans. (C) 2001 Editions scientifiques et medicales Elsevier SAS.