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

Craniomandibular variation in an experimental model for primate dietary variability


1Pathology and Anatomical Sciences, University of Missouri School of Medicine, 2Research Division, Harry S. Truman Memorial Veterans' Hospital, 3Internal Medicine, University of Missouri School of Medicine, 4Biological Sciences, Aerospace and Mechanical Engineering, and Anthropology, University of Notre Dame

Friday 10:45-11:00, Ballroom C Add to calendar

The influence of diet on the evolution and function of the primate skull is a well established topic, bolstered by considerable experimental and comparative work demonstrating craniomandibular plasticity related to elevated loads associated with fracture-resistant diets. The diets of wild primates, however, are often seasonal and thus individuals may experience multiple masticatory loading regimes throughout ontogeny. Indeed, the consumption of seasonal “fallback foods” has been invoked to explain skull form and diversification in early hominins. Yet, exactly how dietary variability affects craniomandibular development and thus the ability to identify seasonality in the fossil record remains unknown. To address this gap, this study raised four dietary cohorts (n=10/cohort) of a well-established experimental species, the laboratory rat, from weaning to skeletal maturity. Two cohorts were fed a stable diet of either solid or powdered pellets. The other two cohorts were fed a variable diet consisting of either solid/powdered pellets for the first half of the study, followed by a shift to the opposite diet. Results indicate that the presence of groups with temporally variable diets decreases the accuracy of classifying mature individuals into their correct dietary cohort based on craniomandibular characters. In order to resolve this issue, this study identifies those characters that best sort individuals by diet. The complexity of correctly classifying plastic morphotypes within a single species may translate into difficulty recognizing the presence of dietary variability in the fossil record, particularly in sister taxa. Furthermore, this research highlights the importance of ontogenetic studies for understanding patterns of feeding behavior.

This research was supported by a NSF DDRIG (1061368), the Wenner-Gren Foundation, and the American Society of Mammalogists. This material is the result of work supported with resources and the use of facilities at the Harry S. Truman Memorial Veteran’s Hospital, Columbia, MO.

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