Craniofacial variation, body size and ecological factors in aboriginal populations from Center Patagonia (2000-200 years BP).
BERNAL, V; BEGUELIN M.; GORDON F.; COBOS V; GONZALEZ P.; LOTTO F
Homo Journal of Comparative Biology
Año: 2014 vol. 65 p. 101 - 114
Previous studies have shown that ecological factors had a significant role in shaping the patterns of craniofacial variation among South American populations. Here, we evaluate whether temperature and diet contributed to facial diversification in small geographic areas. Facial size and shape of 9 osteological samples from Center Patagonia (Argentina) were described using 2D landmarks and semilandmarks. Data on mean annual temperature, diet composition (δ13C and δ15N values) and femoral head maximum breadth, used as a proxy of body mass, were obtained for each sample. We then tested the association of body mass and the ecological variables with facial morphology using spatial regression techniques and a model selection approach. Akaike Information Criterion, yielded to disparate results for both components of facial morphology. The best model for facial size included temperature and body mass proxy, and accounted for more than 80% of variation in size. Lower temperatures were related to larger facial sizes. Body mass was negatively associated with facial size and showed no relationship with the temperature. This suggests a relative independent variation of cranial traits and body mass at the spatial scale studied here. Facial shape was not associated neither with the temperature nor with diet composition, contrasting with the patterns observed at larger spatial scales. Our results point out that the effect of climatic variables on cranial traits might be a source of morphological differentiation not only at large scales but also in small geographic areas, and that size and shape display a differential preservation of environmental signals.