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


Scaling of distance from center of mass to condylar axis in primate mandibles

ELLEN J. PLATTS1, TREVA WALSH1, LIAM HEINS1, LAURA PORRO1, ANDREA B. TAYLOR2 and CALLUM F. ROSS1.

1Department of Organismal Biology & Anatomy, The University of Chicago, 2Department of Evolutionary Anthropology, Duke University

Friday 10:00-10:15, Ballroom C Add to calendar

To understand the evolution of primate feeding systems, we are studying the biomechanical determinants of the scaling of chew cycle duration in primates. This project quantified size-related changes in the distance from the mandibular center of mass to the condylar axis in 51 species of primates, 14 prosimians and 37 anthropoids. Center of mass location was calculated from CT scans using Amira. Relative density of the bone was estimated using Hounsfield numbers of the voxels and marrow space was assigned the density of water. The distance from the center of mass to an axis passing through the backs of the mandibular condyles was calculated. Jaw length was estimated as the distance from the condylar axis to infradentale. The scaling of the distance from the center of mass to the condylar axis relative to jaw length does not differ significantly from isometry in either anthropoids or prosimians. The two groups do not differ significantly from each other in scaling coefficients. Differences in mandible shape between anthropoids and prosimians do not result in differences in scaling of the distance from center of mass to condylar axis. Future work will incorporate more realistic estimates of the location of the axis of rotation.

Funded by the National Science Foundation (BCS 962682)

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