Season of bison mortality in TD10.2 bone bed at Gran Dolina site (Atapuerca): Integrating tooth eruption, wear, and microwear methods

Abstract

The middle Pleistocene assemblage of Gran Dolina TD10.2 bone bed level (Atapuerca, Spain) is composed primarily by bison remains (Bison sp.) belonging to a minimal number of individuals of 60. The mortality and taphonomical features suggest an anthropogenic origin product of mass predation. The large number of mandibles and mandibular teeth of a single species has allowed us to explore the nature of kill events and seasonality of occupations through two methods: eruption and wear-pattern and tooth microwear. Here we combine data obtained on young individuals from tooth eruption and wear and on prime and old adults from tooth microwear. Integrating the results from the two independent and non-destructive methods permits to combine data from the entire population found in the assemblage increasing the sample size. This approach permits to evaluate the seasonality to confirm if the seasonal pattern is similar in young and adults. The integration of the two methods has allowed the identification of two main periods of occupation rejecting a single kill scenario but also permitting to observe phases with low number of individuals which certainly correspond to moments of the year when the site was not occupied. Tooth wear and eruption patterns moreover permit to establish the time of the year when the principal events occurred — one in late spring/early summer and other in early fall. The preliminary results indicate a seasonal mortality pattern on TD10.2 bone bed bison population and a seasonal use of the Gran Dolina site for anthropogenic occupations.