1Department of Anthropology, School of Anthropology and Conservation, University of Kent, UK, 2Department of Zoology, University of Cambridge, UK
Thursday 9:15-9:30, Ballroom B
Human pelvic shape variation has often been interpreted in the light of thermoregulatory adaptation and sex-related obstetrical requirements. Although these factors play a role in explaining human pelvic morphology, their effect cannot be fully understood without first taking into consideration the influence of past population history and neutral evolutionary processes. Here, we use a global dataset of human pelvic variation, quantified using 3D geometric morphometric methods, to represent the complex shape of the innominate in both male and female individuals. Neutrality of pelvic variation was examined via global patterns of apportionment of variance, and by fitting an Out-of-Africa serial founder effect model, which is known to structure neutral genetic diversity. The possible effects of obstetrical constraints on the female pelvis were explored by contrasting neutral patterns in the male and female datasets, and by comparing variation in the false and true pelvis, whereupon greater constraints in the latter might be predicted. Our results reveal an overall neutrality of pelvic variation, and the preservation of population history effects. In accordance with prediction, obstetrical constraints appear to affect differently the true versus the false pelvis, but no difference in their strength was found between sexes. Although our analyses do not contradict the effect of selective pressures and adaptation on the human pelvis, they do highlight a strong neutral component to variation, similar to that previously found for cranial morphology.
This study was funded by the Wenner-Gren Foundation for Anthropological Research, the Ian and Christine Bolt scholarship from the University of Kent, a Sigma Xi grant, two European Union Synthesys grants, the American Museum of Natural History collection study grant, and a University of Kent Ph.D. research scholarship.