Meeting Abstract

88.3  Wednesday, Jan. 7  In vivo bone strain and finite-element modeling of the craniofacial haft in catarrhine primates ROSS, C.F.*; STRAIT, D.; DECHOW, P.C.; RICHMOND, B.; SPENCER, M.; SCHREIN, C.; WEBER, G.; SLICE, D.; University of Chicago; University at Albany ; Baylor College of Dentistry; George Washington University; Arizona State University; Arizona State University; University of Vienna; University of Vienna rossc@uchicago.edu

Hypotheses regarding global or overall deformation regimes in the primate skull remain untested in most taxa, in part because the in vivo bone strain data that provide the direct test of these hypotheses can only be gathered from restricted areas under strain gages. Well validated finite-element models provide a means of evaluating hypotheses regarding global deformation regimes because they not only allow extrapolation beyond the in vivo gage sites, but they also provide a picture of overall deformation. Here we compare in vivo bone strain data gathered from six sites on four Macaca individuals during mastication with strain data from the surface of a finite-element model of the skull of Macaca loaded using external forces estimated using measured muscle cross-sectional areas and masticatory EMG data. The global deformation regime of this validated macaque model is compared with the patterns of deformation of a finite-element model of Pan and with deformation patterns reported by Endo from his in vitro experiments on skulls of Gorilla and Homo. These comparisons reveal a common global craniofacial deformation regime among catarrhine primates, despite diversity in their craniofacial morphology. This suggests that diversity in catarrhine craniofacial skeletal morphology is not associated with variation in the manner in which the skeleton deforms during chewing. This variation must instead be due to selection on other aspects of cranial function, such as food ingestion, gape, vision, olfaction, or protection of soft tissue structures.