Orientation patterns of wildebeest bones on the lake Masek floodplain (Serengeti, Tanzania) and their relevance to interpret anisotropy in the Olduvai lacustrine floodplain

A study of bone orientation patterns at a wildebeest bonebed deposited in the floodplain of Lake Masek (Tanzania) shows that portions of the assemblage exhibit anisotropy probably caused by the combined action of lake transgression and regression, and the watersheet formed during the rainy season, which is also responsible for a large part of the microtopographical features of the surface where the bonebed was formed. Some taphonomic indicators (absence of polished or abraded bone, similar representation of Voorhies' anatomical groups I and III) show that the anisotropic trend was formed under very low-energy conditions. Anisotropy can be locally produced in autochthonous assemblages. Bone orientation patterns need to be combined with other taphonomic techniques to determine the depositional nature of any given assemblage.