Variación morfológica en hokkaido: un estudio craneofuncional

Abstract

Cranial differentiation is an indicator of relationships between populations and between populations and their environment. For instance, populations that inhabit cold climates show a particular nasal morphology that favors warming and moisturizing of the inspired air, while populations that consume diets with different consistencies show variation in masticatory structures. Hokkaido registers human occupation since the Pleistocene. After the postglacial and up to 4.300 BP the climate was quite warm; followed by a much colder period. Hokkaido was inhabited by Jomon hunter-gatherers-fishers. Their descendants, Ainu people, continued the same subsistence pattern but adding some seasonal agriculture. The purpose of this study is to compare cranial morphology of Jomon and Ainu, through the craniofunctional method, in order to verify if groups vary as a consequence of directional forces. We registered landmarks and applied geometric-morphometrics and estimated measurements and indices in neural, facial, masticatory and nasal indices. The main differentiation of Ainu occurred by a change in the nasal shape, without changes in size, and a reduction in masticatory volume, mainly in width. The pattern obtained fits with predictions: aborigines of Hokkaido evolved during the last five millennia under climatic stress and with less masticatory stress.