Special issue: Australopithecus sediba --- The Anatomy of the Lower Limb Skeleton of Australopithecus sediba

Abstract

The functional anatomy of the lower limb skeleton has featured prominently in reconstructions of locomotion in early hominins. Based on recent discoveries, many scholars now suggest that Plio-Pleistocene hominins experi-mented with different forms of bipedalism, due in part to variation in how arboreally adapted some hominin spe-cies remained. The 1.977 Ma Australopithecus sediba fossils from Malapa, South Africa, are central to the hypothesis of locomotor and kinematic variation in early hominins. Here, we provide detailed anatomical descriptions of the thigh, leg, and foot of Au. sediba and present additional comparative and functional analyses. Australopithecus sedi-ba possesses, in general, an australopith-like hip and knee, though the anatomy of these joints differs in important ways from other australopiths. 3D geometric morphometrics and comparative linear and angular analyses dem-onstrate that each individual foot bone in Au. sediba displays a mosaic of anatomies conducive for both terrestrial bipedalism and arboreality. These findings demonstrate both the taxonomic validity of Au. sediba and suggest that australopiths had both diverse locomotor strategies and variation in locomotor kinematics. This special issue is guest-edited by Scott A. Williams (Department of Anthropology, New York University) and Jeremy M. DeSilva (Department of Anthropology, Dartmouth College). This is article #7 of 9.