Human Craniofacial Variation among Pacific Rim Populations through the Holocene: A Test of the Coastal Migration Hypothesis using 3D Morphometric Methods.

摘要

This dissertation research is directed at understanding migration patterns of the New World's first inhabitants. Although the question of the origins of the first Americans has been resolved through molecular research, the migration routes of the earliest inhabitants continue to be intensely debated among scholars. The traditional migration hypothesis maintains that the first Americans traveled by foot across the Bering Land Bridge and into the interior of North America in search of megafauna. However, recent archaeological, genetic, and bioarchaeological research suggests that a Pacific Rim coastal migration may have occurred during the initial colonization of the Americas. Based on these lines of evidence, this research seeks to investigate whether the skeletal morphology of the earliest American inhabitants show affinities to skeletons from the Pacific Coast, supporting the coastal migration model, or the interior, supporting the Clovis model.;To investigate this question, three-dimensional (3D) imaging and geometric morphometric methods were used to examine craniofacial variation among early Holocene Paleoamerican (skeletons >8,000 cal BP) and a comparative Holocene (7,500 - 1,000 cal BP) sample from 30 coastal and interior sites in North and South America. A NextEngine 3D laser scanner was used to create high resolution models of human crania and a digital replica of the original cranium, which were then used to record craniofacial landmarks. The coordinate data were used to assess variation using a suite of 3D geometric morphometric procedures. The assessments of cranial variation among the comparative sample of coastal and interior groups showed that the coastal populations are slightly more heterogeneous than the interior groups. The computed distances showed closer affinities between the Paleoamerican and coastal samples, respectively. Procrustes distances were smaller between several Paleoamericans and the coastal samples, but some Paleoamericans also were also very similar to interior samples. The posterior probabilities classified all the Paleoamerican skeletons in coastal groups, providing more definitive support for the Coastal Migration Hypothesis. This research is in accordance with recent archaeological, genetic, and geological studies that support an early coastal migration during the initial peopling of the New World.