Variation in mobility and anatomical responses in the Late Pleistocene

Abstract

Diachronic changes in European Late Pleistocene humans indicate anatomical changes in the lower limb associated with decreased mobility. A more global perspective suggests that similar trends toward reduced mobility occurred simultaneously in other parts of the Old World, but Late Pleistocene populations in non-European regions demonstrate significant variation in femoral and tibial cross-sectional geometric properties that are inconsistent with behavioral interpretations. Samples of Late Pleistocene early modern humans from Europe, Northern Africa, and Asia are analyzed to assess regional variation in postcranial trends. Cross-sectional geometric properties for midshaft femora and tibiae and measures of articular surface areas and mechanical efficiency are evaluated between samples. Regional Late Pleistocene samples are differentiated by measures of diaphyseal robusticity. Northern African samples are uniquely robust, particularly at the level of the midshaft tibia. Relative to other regional samples, the Asian sample has distinctly gracile femoral and tibial diaphyses. Although this may indicate reduced mobility, this sample also demonstrates relatively high mechanical efficiency at the knees and hips, which may point to an alternative mechanism for counteracting loading on the lower limbs from high mobility or terrain differences.