1Department of Anthropology, The Pennsylvania State University, 2Department of Anatomical Sciences, Stony Brook University, 3Center for Quantitative Imaging, EMS Energy Institute, The Pennsylvania State University
Thursday All day, Clinch Concourse
The three-dimensional trabecular bone structure of the femoral head of strepsirrhines has been related to locomotor differences, particularly between leaping and non-leaping taxa. The goal of this study is to assess trabecular bone structural adaptation in the proximal femur of strepsirrhine primates by using multivariate discriminant function analyses to categorize extant species by locomotion and to predict locomotor behaviors in fossil primate species. The proximal femur of 37 individuals from six extant primate genera (Microcebus, Cheirogaleus, Galago, Loris, Otolemur, Perodicticus) and three extinct primate taxa (Karanisia, Omomys, Shoshonius) were scanned on a high-resolution computed tomography system with voxel dimensions below 0.04 mm. Trabecular bone structural features (bone volume fraction, degree of anisotropy, trabecular thickness, number, and spacing, and connectivity density) were quantified in two volumes of interest extracted from the articular region of each bone. These features were corrected for body mass and used in a multivariate discriminant function analysis both to determine the suites of bony characteristics that differentiate locomotor and taxonomic groups and to predict the position of the three fossil specimens. Results for extant species show a strong separation of Galago, Loris, and Perodicticus, suggesting a distinct locomotor functional signal in the femoral head trabecular bone of these primates. Fossil specimens show clear similarities to specific locomotor groups with the basal lorisiform Karanisia plotting closest to the slow quadrupedal Loris and the larger-bodied quadrupedal leaping Otolemur.
Grant Support: NSF BCS- 0617097 (TMR), NSF BCS-0819186 (ERS)