The ATD6-5 mandibular specimen from Gran Dolina (Atapuerca, Spain). Morphological study and phylogenetic implications

Metric and shape features of the Lower Pleistocene mandibular specimen ATD6 05 from the level 6 of Gran Dolina site (Atapuerca, Spain) are compared wit h a large sample of fossil hominid mandibles. The analysis shows that ATD6- 5 displays a generalized morphology largely shared with both African and Eu ropean Lower and Middle Pleistocene samples. However, distinctive African t raits, such as corpus robustness and strong alveolar prominence, are absent in the Gran Dolina specimen. At the same time, none of the apomorphic feat ures that characterize Middle and early Upper Pleistocene European hominids can be recognized in ATD6-5. Finally, the Gran Dolina specimen displays a remarkable position of the mylohyoid groove, only comparable to that found in immature specimens of Homo ergaster, and very rarely in adult H. sapiens . The morphology of ATD6-5 supports the hypothesis of an African origin for the first Europeans with subsequent phylogenetic continuity with Middle Pl eistocene populations in Europe. These findings are consistent with H. ante cessor being the last common ancestor of Neandertals and H. sapiens. (C) 19 99 Academic Press.