Meeting Abstract

P3.56  Tuesday, Jan. 6  The Relationship Between Muscle Attachment Site Size and Function in the Avian Hind Limb BURCH, Sara H.; Stony Brook University, NY sara.burch@stonybrook.edu

The utility of osteological correlates of muscle attachment sites (e.g., scars, crests and tubercles) in the reconstruction of function and behavior in vertebrates is controversial. Whereas not every muscle leaves a scar, it has been suggested that differences in the relative size, strength and/or function of a muscle may be reflected in the relative development of an osteological correlate. This relationship has been systematically studied thus far only in an intraspecific context. Birds exhibit a wide range of hind limb locomotor adaptations ranging from cursoriality (Paleognathiformes) and diving (Gaviiformes) to predation (Falconiformes) and scansoriality (Piciformes), but the musculature of avian hind limbs is relatively conserved across taxa. This makes birds an ideal group for examining functional correlates of muscle attachment site size. Several bony crests and projections of the femur and tibia, each representing the attachment site of a functionally relevant muscle, or group of muscles, were photographed and measured in multiple avian taxa, representing eight distinct locomotor categories. The area of each osteological correlate was regressed against midshaft diameter of the bone, and an analysis of covariance indicated that the functional categories differed significantly (p<0.05) from each other for each muscle examined. Certain taxa, notably divers, climbers and cursors, exhibited highly specialized functional adaptations that correlate to either increased or decreased muscle use at that attachment site. These results suggest that variation in osteological correlates is likely to have utility when reconstructing functional or behavioral categories from osteological specimens, including those of fossils.