Critique of 'Australopithecus afarensis' as a single species based on dental metrics and morphology

Abstract

Leonard and Hegmon (1987) compare a series of dental metrics of 'Australopithecus afarensisJohanson, White, and Coppens, 1978' with criteria for modern apes, to test the hypothesis that 'A. afarensis' represents a single species. They also compare the morphology of the lower third premolar. The dental breadth of 'A. afarensis' shows a wide range of variation, particularly in the lower third premolar morphology which displays greater variation than in modern apes-yet the study concludes that the single species hypothesis cannot be rejected. The study is flawed by applying criteria for pongids inappropriate for a hominid. When 'A. afarensis' is compared with criteria for hominids, the range of variation in dental size, breadth, and third premolar morphology is greater than that in any hominid species. The single species hypothesis is, therefore, once again rejected. Moreover, the name 'A. afarensis' is preoccupied by Praeanthropus africanus (Weinert) and must be dropped. © 1989 Japan Monkey Centre.