Craniofacial morphology in Austrian Early Bronze Age populations reflects sex-specific migration patterns

The Early Bronze Age (2.300-1.500 BC) in lower Austria consists of three synchronous regional manifestations (Únetice, Unterwölbling, and Wieselburg cultures). The bearers of these cultures inhabited a relatively small geographic area and shared similar ecological conditions, but previous studies revealed population differences in skeletal morphology. We analyzed the cranial morphology of 171 individuals of these populations with a geometric morphometric approach in order to compare different migration scenarios. We find significant mean form differences between populations and between sexes. In a principal component analysis, the Wieselburg population, located southwest of the Danube, largely separates from the Únetice population north of the Danube, whereas the southwestern Unterwölbling group, which played a central role in trading bronze objects, overlaps with both. The Böheimkirchen group, inhabiting the southwestern Danubian area in the later phase of the Early Bronze Age, differs from the chronologically older Unterwölbling group. Geographic distance between six sites and position relative to the river Danube accounted for 64% of form distance variation; the effect of the river Danube was considerably larger than hat of geographic distance per se. As predicted for a patrilocal system in which females have a larger marriage domain than males, we found that female mean forms are more similar to each other than male mean forms. Geographic conditions explained more than twice as much variation in females as in males, suggesting that female migration was more affected by geographical constraints than male migration was.