Functional Adaptation of the Human Facial Skull to the American Ecosystems of the Late Pleistocene

Abstract

This study investigates the degree to which the facial diversity of Amerindian hunter-gatherers reflects their evolutionary history and their adaptation to the ecosystem whose resources they exploited. 417 undeformed skulls (231 male and 186 female), from various collections and museums in Europe and America, were studied. The technique of W.W. Howells and discriminant analysis were applied to 17 facial variables from four Amerindian series and the Greenland Eskimo series, in both sexes. Cranial size (PENSIZE) and shape (C-Scores) were examined separately. By removing the cranial size, a hidden and new information emerged. Both Amerindian marine and terrestrial hunters studied are well distinguished from the Eskimos. The main differential character in facial variation are both subnasal and alveolar prognathisms, with wide ranges of intragroup diversity. Both prognathisms, alveolar and subnasal, are variable, although more marked in the women of all the samples studied. The Selknam (Tierra del Fuego) and Arikara (South Dakota) men are the least prognathic. The morphological variation found is not associated with a specific ecosystem (marine or terrestrial). Our analysis reflects the evolutionary history of the Amerindians with significant differences due to functional adaptation which modified their faces.