Surface modifications of the Sima de los Huesos fossil humans.

The sample of fossil human bones from the Sima de los Huesos, Atapuerca, has been analysed to trace parts of its taphonomic history. The work reported here is restricted to analysis of the skeletal elements preserved and their surface modifications. Preliminary plans of specimen distribution published 6 years ago indicate that the skeletal elements are dispersed within the cave, but more recent data are not yet available. Most of the fossils are broken, with some breakage when the bone was fresh and some when already partly mineralized, both types showing some rounding. There are few longitudinal breaks on shafts of long bones and so very few bone splinters. All skeletal elements are preserved but in unequal proportions, with elements like femora, humeri and mandibles and teeth with greater structural density being best represented. There is no evidence of weathering or of human damage such as cut marks on any of the human assemblage, but trampling damage is present on most bones. Carnivore damage is also common, with some present on more than half the sample, but it is mostly superficial, either on the surfaces of shafts and articular ends or on the edges of spiral breaks. The sizes and distribution of the carnivore pits indicate extensive canid activity, and this is interpreted as scavenging of the bones in place in the cave. Indications of tooth marks from a larger carnivore indicate the activity possibly of a large felid: the marks are too large to be produced by small canids, with the larger marks concentrated on spiral breaks on the more robust bones, and there is no evidence of bone crushing and splintering in the manner of hyaenas. The nature of the SH human assemblage is also consistent with accumulation by humans, the evidence for this being the lack of other animals, especially the lack of herbivorous animals, associated with the humans, and the high number of individuals preserved.