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

Masticatory biomechanics and hard object feeding: cranial adaptations in Cercocebus torquatus


1Centre for Anatomical & Human Sciences, Hull York Medical School, University of York, UK, 2Department of Engineering, University of Hull, UK

Thursday 8:15-8:30, Broadway III/IV Add to calendar

Mangabeys (Cercocebus torquatus) and Macaques (Macaca fascicularis) are two closely related taxa that present variations in craniofacial form and diet. In comparison with Macaques, Mangabeys are identified as hard object feeders, relying extensively on hard nuts. As such comparisons of how the skulls of these two species respond to mechanical loads may provide an insight into cranial adaptations to masticatory load production and resistance.

Multibody dynamic analysis (MDA) was conducted for the two species. These models are capable of predicting muscle activation patterns for a specified biting task. Two biting tasks were simulated at each tooth; 100N bites, and maximum possible bites, predicted by the model. These loadings were then applied to finite element models of the same specimens. In order to compare the way in which two skulls respond to the predicted loading regimens the results are analysed within the multivariate framework of geometric morphometrics (GMM).

The results of the MDA indicate that the Macaque is capable of producing biting forces similar to Cercocebus. Yet given the same biting task the results of the finite element analysis (FEA) and GMM analyses indicate that the degree of overall skull deformation is slightly smaller in Cercocebus than Macaques. These species also differ in how they deform, globally (GMM) and locally (strains). In particular, differences in strain are predicted in the alveolar region. The extent to which such differences reflect dietary adaptations will be considered. This study also highlights the potential combined application of MDA, FEA and GMM to comparative functional analyses.

This study was funded by the BBSRC, grant numbers BBE0138051 and BBE014259.

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