Gran Dolina-TD6 and Sima de los Huesos dental samples: preliminary approach to some dental characters of interest for phylogenetic studies

Abstract

The Sima de los Huesos (SH) and Gran Dolina-TD6 sites in Sierra de Atapuerca (Spain) have each yielded an impressive fossil hominin sample representing Middle Pleistocene and Late Lower Pleistocene European populations, respectively. Paleontological evidence, paleomagnetic analyses, and radiometric dates (U/Th) suggest an interval of 400 to 500 ky for the SH hominins. At Gran Dolina, radiometric dates (ESR and U-series) combined with paleomagnetic analyses and fossil evidence indicate an age range between 780 and 860 ky for the Aurora Stratum of the TD6 level where the fossil hominins were found. We have assigned the SH hominins to the Homo heidelbergensis species, whereas the TD6 hominins are representative of Homo antecessor, the species named in 1997 (Bermùdez de Castro et al., 1997) to accommodate the variability observed in the TD6 fossil human assemblage. Dental collections of the SH and TD6 sites include more than five hundred deciduous and permanent teeth. The detailed description and morphological comparison of the Atapuerca dental samples will be published elsewhere in a near future, but the examination of an extensive human fossil record, has already revealed some dental characters we consider crucial for phylogenetic studies. We describe those characters and provide an overview of their distribution across the hominin fossil dental record. On the basis of these traits we explore some questions about the phylogenetic relationship between TD6 and SH hominins as well as the evolutionary scenario of these two populations.