The 81st Annual Meeting of the American Association of Physical Anthropologists (2012)

Dietary microfossils from Rapa Nui dental calculus: does regional variability provide evidence for subsistence practices?


1Department of Anthropology, Idaho State University, 2Center for Archaeology, Materials and Applied Spectroscopy

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Microfossils extracted from dental calculus represent dietary and/or occupational artifacts embedded during life, offering a direct view of human-environment subsistence relationships. While recent studies have reported on the successful recovery of microfossils from calculus, this study is the first to employ high frequency sampling from a large archaeological human skeletal collection (n = 114/866 specimens, 13.2%). In addition to presence-absence data, our dental calculus sampling strategy provides additional evidence for subsistence activities and the geographic distribution of important foods. We recovered dental calculus from teeth of 114 Rapa Nui skeletons from 12 important regional sites dating from the late prehistoric and early protohistoric era (AD 1680 – 1750), employing SEM-EDS microanalysis to identify and quantify major taxa of embedded phytoliths and diatoms (n = 16,484). The majority of phytoliths were classified as globular echinate (n = 4,535), characteristic of Aracaceae (palm). Small numbers of grassy (Poaceae; n = 266) and unidentified phytoliths (n = 17) were also recovered. These results suggest a restricted diet throughout the island in the late prehistoric period and argue against the traditionalist notion that the people of Easter Island committed “ecocide” by cutting down the island’s palm trees, or that commensal introduced species such as the Polynesian rat (Rattus exulans) extirpated the palms prior to European contact. Our study demonstrates that geographically extensive, high frequency sampling for calculus-derived microfossils permits testing precise hypotheses about dietary adaptations and species persistence over relatively brief archaeological timescales, something not possible with small-scale calculus sampling.

This study was partially funded by the National Science Foundation, grant number BCS 0821783 and PHY 0852060.

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