Post-Pleistocence diachronic change in East Asian facial skeletons: the size, shape and volume of the orbits

Globally there was a reduction in the size and robusticity of the human orofacial skeleton and dentition after the Pleistocene. There was also diachronic change in brain size and skeletal mass in general. Anthropologists have developed numerous models in explanation of the evolutionary process, with the majority linked to the cultural developments of the Neolithic. These cultural models are challenged by the skeletal evidence from societies with contrasting culture histories. In China there is a reduction in facial breadth, height and prognathism, posterior tooth size, brain volume and cranial robusticity from the Neolithic to the modern period. However, the height of the orbits increases rather than decreases. Examination of the structural relationships between orbit and facial dimensions in Tohoku Japanese and Australian Aboriginal crania suggests a steady reduction in orbit volume in China. This may have resulted in a more anterior placement of the eyeball and associated structures in modern East Asians than in their Neolithic counterparts.