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


Reconstructing stress episode chronology and periodicity among Late/Final Jomon period foragers using incremental microstructures of enamel

DANIEL H. TEMPLE.

Department of Anthropology, University of North Carolina Wilmington

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This study reconstructs stress episode chronology and periodicity among Late/Final Jomon period (5000 through 2300 BP) foragers from Honshu and Hokkaido using linear enamel hypoplasia (LEH) defects. Age-at-defect formation was calculated by dividing each tooth into deciles and placing each LEH defect into a chronological framework based on 6-month intervals. Periodicity was calculated by counting the number of perikymata between successive LEH defects and multiplying this number by a constant associated with perikymata formation. On Honshu, median age-at-defect formation was 3.4 years, while 66% of all LEH defects were estimated later than 2.9 years. On Hokkaido, median age-at-defect formation was 3.1 years, while 61% of all LEH defects were estimated later than 2.9 years. Modal stress episode periodicity on Honshu was 0.1 years (35.1%), while modal stress episode periodicity on Hokkaido was 0.2/0.3 years (26% each). Average stress episode periodicity on Honshu (0.2 years) was significantly lower than average stress episode periodicity on Hokkaido (0.3 years). Average ages-at-defect formation are associated with tooth crown geometry for both samples, though LEH defects occurring after 2.9 years may reflect weaning stress in accordance with nitrogen isotope analysis. The shorter periodicity of stress episodes found among prehistoric Jomon foragers from Honshu suggests repetitive stress cycles that may not be traced to seasonality, and instead, may reflect random nutritional insufficiencies. In contrast, Jomon foragers from Hokkaido appear to have experienced stress episodes along approximately 3-month intervals, which may track with accentuated seasonal shifts in this region.

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