1Department of Anthropology, Texas A&M University, 2Institute for Human Evolution, University of the Witwatersrand
Saturday All day, Plaza Level
A preliminary phenetic analysis of the Australopithecus sediba cranium, UW88-50, was conducted to assess the nature and degree of phenetic affinity between A. sediba and other australopiths and early Homo. The dataset was comprised of 10 craniofacial measurements taken from 16 hominin crania preserving relatively intact facial skeletons. The dataset was analyzed using principal components, discriminant function, and Euclidean distance matrix analyses. Analysis of the raw data revealed several clusters of specimens that broadly conform to taxonomic groupings. The three ‘robust’ australopith taxa form one cluster along the first principal component (53.2% of variance). A. africanus forms another grouping along the first principal component, while KNM-ER 1470 groups with a cluster of H. erectus specimens. UW88-50 plots most closely to SK847 and KNM-ER 1813 along the first principal component, with all three plotting in between the groupings of A. africanus and H. erectus + KNM-ER 1470. When the data are size-standardized, UW88-50 clusters closely with early Homo specimens along the first and second principal components (96.2% of variance), with groupings of A. africanus and the ‘robust’ australopiths forming additional clusters. In both the raw- and size-standardized data analyses, Stw53 and OH24 grouped most closely with specimens of A. africanus, suggesting that these two specimens do not share their closest morphological affinities with Homo. The cranium of A. sediba possesses substantial morphological affinities with specimens currently classified as Homo, though we would caution that taxonomic diagnoses based on isolated skeletal regions require additional supporting evidence from other regions of the body.