Meeting Abstract

P3.164  Monday, Jan. 6 15:30  Limb Joint Surface Area Ratios in Living and Extinct Carnivorans SQUYRES, N.S.; Johns Hopkins University nsquyre1@jhmi.edu

Differences in relative humeral and femoral head size are thought to be related to locomotor capabilities in carnivorans. Measures of humeral and femoral articular surface size, shaft robusticity, and relative femoral neck size were collected in 148 individuals of 21 carnivoran taxa to test this hypothesis. The ratio of humeral/femoral head size appears to differ between more and less arboreal taxa, with more arboreal taxa generally having relatively large femoral heads. Taxa that emphasize forelimb use in activities such as digging and large prey capture have relatively large humeral heads. Species with relatively large femoral heads do not necessarily have relatively robust femoral shafts, but do have relatively small femoral necks. This suggests that increases in femoral head size are driven by the need for greater hip excursions rather than by greater hind limb loading during arboreal movement. Application of these data to extinct carnivorans Miacis, Didymictis, and Vulpavus confirms previous conclusions about locomotor behavior in these genera based on other aspects of postcranial morphology.