Ecogeography-related humerus morphological variation within southern Patagonia hunter-gatherers

Southern Patagonian (SP) hunter-gatherers were adapted to diverse environments and subsistence strategies. However, ecological factors affecting variation in upper-limb proportions have not been thoroughly examined. This study analyses whether size-related humerus morphology differs among hunter-gatherers from SP according to specific subsistence economy and physical environment.

Thirty-nine left humeri of adult individuals were selected from well-documented SP archeological sites. Individuals were grouped into terrestrial or maritime hunter-gatherers based on diet-related archeological and stable isotope records. Five humeral head and diaphyseal metrics were taken and statistically compared among subsistence strategy groups across four ecogeographic subregions.

Terrestrial hunter-gatherers exhibit greater humeral dimensions compared to maritime hunter-gatherers. An ecogeographic pattern of humerus size variation was also found, showing significant size reduction in individuals from southern regions.

The previously determined low genetic variability within hunter-gatherers from SP suggests that the physical environment played an important role in humeral adaptive plasticity. These findings also highlight morphological upper-limb responses to bioclimate factors derived from SP subregions.