Matt Cartmill

I have recently begun preliminary work on a course of experimental research into the origins of human bipedalism. Known remains of the earliest bipedal human precursors (Australopithecus afarensis in East Africa and Australopithecus africanus in Southern Africa) exhibit two odd autapomorphies not found in Recent large-bodied hominoids: an exaggerated interacetabular distance, and an elongated lumbar segment of the vertebral column. From published studies of human and bird bipedalism, from theoretical expectations based on my earlier studies of primate locomotion, and from what is known about the morphology and habitat of the earliest hominids, I hypothesize that these singular specializations, which do not fit received models of the early evolution of hominid bipedalism, may represent adaptations for running. Experimental studies of locomotion in humans are being undertaken in collaboration with our Postdoctoral Fellow Daniel Schmitt to test various hypotheses concerning the possible functional significance of these australopithecine peculiarities. Preliminary findings on pelvic rotation in human running were presented at the AAPA meetings in April.