A new perspective on the population history of the pre-Incan South Central Andes through analysis of the dental morphological data

The complex population history of the pre-Incan South Central Andes has been investigated by a multitude of archaeological and anthropological analyses that have laid a foundation for the understanding of population movements in the region. Of particular interest is the role played by the Tiwanaku Empire in the peopling of the Osmore and Azapa Valleys, respectively in southern Peru and northern Chile. In the present paper, we combine the dental morphological data available in the literature for both valleys, with new data from Tiwanaku and from sites in central and southern Peru in order to reach a better understanding of the biocultural dynamics exerted by the local Empires’ political expansions. Sixteen sites dated from the Archaic to the Late Intermediate periods were analyzed for 39 dental traits. Statistical analyses revealed a close affinity between Chen Chen, a supposed Tiwanaku outpost in the Middle Osmore Valley, and the Moche, the Wari, as well as the actual Tiwanaku sample. Coastal sites from both Valleys gather together, separating from the Middle Valley cluster, indicating that the dynamics that occurred in the Middle Osmore Valley did not affect the population on the coasts. At the same time, continuity can be highlighted between the Azapa Valley sites, both at coastal and valley level. The results obtained are in contrast with previous hypotheses, and stress the need to re-evaluate the role of the Tiwanaku culture in the peopling of both the Osmore and the Azapa Valleys and its ties to the later coastal Chiribaya culture.