The 82nd Annual Meeting of the American Association of Physical Anthropologists (2013)


A study of postcranial indices, ratios and body mass versus eco-geographical variables in an assessment of phenotypic adaptation to climatic conditions

NORIKO SEGUCHI1, CONRAD B. QUINTYN2 and HIROFUMI TAKAMUKU1.

1Department of Environmental Changes, Graduate School of Social and Cultural Studies, Kyushu University, 2Department of Anthropology, Bloomburg University of Pennsylvania

Thursday 9:00-9:15, Ballroom B Add to calendar

Human body size and shape exhibit considerable global variation. According to Bergmann’s and Allen’s rule, populations in cold climate exhibit larger body and smaller/shorter extremities than populations in hot climate. As such, skeletal limb size proportions may shed light on human evolution and climatic adaptation. In this perspective, we investigate ecogeographic significance of human postcranial diversity.

We used brachial-crural indices; femur head breadth-femur length ratio; femur head breadth-lower limb length ratio; and body mass as indicators of phenotypic climatic adaptation among 11 historic and recent sample groups from Africa, Europa, South Asia, East Asia, and North America.

Data were subjected to principal components analysis and Manly’s non-parametric correlation tests. The non-parametric correlations were tested between pc scores, indices, ratios, body mass, and ecogeographic variables: latitude, longitude, minimum temperature, and maximum temperature. Significance was calculated after 10,000 permutations in a two-tail test (α = 0.05).

Principal components plots exhibit geographic clines from South to North. The first principal component scores (loadings especially for body mass and femur head breadth to femur length ratio) shows weak but statistically significant correlations with latitude and minimum temperature, and a very weak but statistically significant correlation with maximum temperature. Only crural index shows a strong and statistically significant correlation with latitude when variables are tested separately. All significant weak correlations between the regressions of PC scores and latitude, minimum temperature, and maximum temperature indicate some trends in the data for a potential selective mechanism or adaptive pathway occurring in the indices, ratio and body mass.

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