The 89th Annual Meeting of the American Association of Physical Anthropologists (2020)

Identification and Implications of Carious Lesions in a Large Sample of Early Eocene Stem Primates from the Bighorn Basin of Wyoming


Anthropology, University of Toronto Scarborough

April 17, 2020 , Platinum Ballroom Add to calendar

Caries is a dental disease resulting from the consumption of high levels of carbohydrates, commonly fruit in non-human primates, and therefore provides insight into patterns of diet. The disease is common among modern populations of humans and some non-human primates and has been identified in primates spanning the Plio-Pleistocene and even the Miocene. However, very little is known about caries in more ancient primate taxa, particularly during the Eocene, when global and local temperatures fluctuated dramatically. The microsyopid plesiadapiform, Microsyops latidens, is a stem primate known from a sample of nearly 1,000 stratigraphically controlled specimens from the early Eocene of Wyoming’s Bighorn Basin. Because this sample is large, stratigraphically controlled, and spans a previously identified hyperthermal period, it allows for the characterization of patterns of variation through time in the context of climatic change. Using high-resolution micro-CT data, we identified occlusal caries in over 8% of the individuals in our sample (MNI = 960), which is relatively high compared to modern primates. Moreover, we identified two dramatic spikes in caries prevalence, with as many as 25% of individuals characterized by the presence of lesions. Although there are no climatic data for the period relevant to the latter of these two spikes, the earlier spike coincides with the previously identified period of temperature increase. Our analysis therefore provides a framework for identifying caries in early primates and suggests that changes in climate likely affect patterns of diet, particularly levels of fruit consumption, and dental health in early Eocene primates.

Funding was provided by a NSERC Discovery Grant to MTS and a University of Toronto Department of Anthropology Pilot Funding Grant to KRS

Slides/Poster (pdf)