Enamel hypoplasia in Northeast China: Evidence from Houtaomuga

The importance of the study of archaeological sites outside the Yangtze and Yellow River Valleys has been increasingly recognized as these peoples also played important roles in the formation of Chinese civilization. In Northeast China the boundary between sedentary agriculturists and nomadic pastoralists has fluctuated over the vast Dongbei Plain (Northeast Plain) providing opportunities to explore relationships between stress exposure, subsistence, and cultural complexity. The human remains for the present study were recovered from the upper level of the Houtaomuga site (2250-2050 BP) on the Dongbei plain, Northeast China, and categorized as Hanshu II cultural period. Inhabitants are believed to have practiced mixed hunting-gathering-fishing with limited millet cultivation. This study explores the dental expression of stress episodes in this period. Our results show overall 72.73% of the individuals examined (40/55) exhibited linear enamel hypoplasia (LEH). Additional data from labial/buccal casts from 105 teeth of 30 individuals from the upper level of the site reveal the duration of growth disruption, counted as numbers of perikymata in the occlusal wall of each hypoplastic defect, ranged from 2 to 14. Stress episodes, calculated as ranging from 17 to 28 days at the low end to 98 to 154 days for the longer duration events, are consistent with values reported from sites in other parts of the world. Examination of anterior permanent teeth for LEH also indicates that infants and children of Houtaomuga experienced extremely high levels of stress, sufficient to affect the developing teeth of almost all the inhabitants. In future examination of enamel hypoplasia of the pastoralists from the Neolithic levels of the site can provide time depth for this study of population stress, and facilitate our understanding of the changes in lifeways and adaptive strategies across subsistence transitions and climate change in Northeast China. (C) 2015 Elsevier Ltd and INQUA. All rights reserved.