Office of Research, University of Washington, Anthropology, University of Oregon
Thursday All day, Clinch Concourse
The hand of fossil Theropithecus has been relatively widely studied, however, the carpal elements are often undescribed or unidentified (Jolly, 1972; Krentz, 1993b; Jablonski, 2002b). While carpal elements are rare in the fossil record, KNM-WT 39368, a partial skeleton of Theropithecus brumpti, preserves the full suite of carpal bones. For this study, the carpals were first identified and then noteworthy or functionally relevant measurements taken. The T. brumpti carpals were visually compared with Papio hamadryas anubis and Theropithecus gelada. Differences, when found, were noted. Overall, the carpal bones are remarkably similar within cercopithecines. However, in the T. brumpti carpal suite there are a few features that suggest terrestriality: 1) slight medial expansion of head of the capitate, 2) flattening on the distal portion of the triquetral facet of the hamate (thereby liming range of extension) and 3) relatively long hamate facet on the triquetral. Whitehead (1993) described carpal features that may signal digitigrade locomotion, some of these are present in T. brumpti: a lack of distinction between the MCIV facet and MCV facet on the distal hamate and large and hooked hamate hamulus. Among the extant primates, only the relatively terrestrial species adopt digitigrady. These data, taken together with recent re-analyses of the T. brumpti postcrania further refute previous hypotheses about arboreality in T.brumpti and confirm probability of terrestrial locomotion.
This study of was funded by the Geological Society of America, the Paleontological Society, the National Science Foundation, the Leakey Foundation and the University of Oregon.