Shape and size changes in the human skull: the effect of dietary transitions

Abstract

We evaluate different skull subregions to detect if changes in food consistency have an effect on size and shape variation. Three population economic transitions and three non-transitional populations were analyzed. Ninety 3D landmark coordinates were digitized in a sample of 459 skulls and analyzed using geometric morphometry. Additionally, the bite force was estimated for each group. Our results indicate size differences between transitions and cranial regions. The shape changes are concentrated in the  temporal and masseter muscles insertion, which show an anteroposterior lengthening in the hard diet groups in relation to the soft diet groups. Other important changes occur in the zygomatic arch, which is wider in the hard diet groups. The bite force is overall higher in the groups representing the toughest diets.