FUEGUIAN CRANIAL MORPHOLOGY - THE ADAPTATION TO A COLD, HARSH ENVIRONMENT

Craniometric data from the three extinct tribes that inhabited Tierra del Fuego (Selk'nam, Yamana, and Kaweskar) were gathered following How ells's measurement technique. We studied 180 skulls preserved at thirt een different institutions. Analysis of variance (ANOVA) between group s showed that morphological similarities among Fueguian groups are far more important than some differences between marine (Yamana and Kawes kar) and terrestrial (Selk'nam) groups. A principal component analysis (PCA) generated from the correlation matrix shows that Fueguians fall as outliers with respect to the typical Mongoloid morphology. In addi tion, a UPGMA tree generated from a squared Euclidean distance matrix indicates that Fueguian groups have a morphological pattern that is ve ry distinct from that of other present-day Amerindian groups, with the exception of the Eskimos. One of the variables that contributes subst antially to the differentiation of Eskimos and Fueguians is the nasal height. This suggests that nasal morphology in both groups could be a response to adaptive pressures related to the cold environment. Howeve r, other morphological particularities of Fueguian skulls, such as cra niofacial robustness and variables of craniofacial width, can be attri buted to a large masticatory stress. As a whole, the morphological fea tures of Fueguian groups can be regarded as a general adaptive respons e to a very harsh environment, along with the retention of some plesio morphic features. Assuming that the initial entry in Tierra de Fuego t ook place around 10,000 years BP, before the disappearance of the last land bridges in the Magellan Straits, then this adaptation might have arisen in a relatively short period, hastened by the extreme environm ental conditions. (C) 1997 Wiley-Liss, Inc.