Early hominid phylogeny

Abstract

This paper describes a quantitative cladistic study of hominid phylogeny. Measurements between homologous landmarks were taken from a variety of fossil hominids and from 140 modern primate specimens. The measurements were confined to the cranium, mandible and dentition. The effect of size was removed from the data using an adaptation of Kazmierczack's transformation, and the transformed data were coded directly into discrete, ordered character states. Cladograms were constructed for different OTU combinations, using the PAUP phylogeny program to find minimum length (maximum parsimony) trees. The trees were rooted by including a single hypothetical outgroup which was calculated from a previous, separate, analysis of six extant primate taxa. The most parsimonious cladogram for conventionally-defined hominid taxa is consistent with the phylogenetic hypothesis advanced by Kimbel et al. (1984). Subdivision of early Homo, according to criteria that emphasize the size variation in this group, has little impact on the phylogenetic relationships of the group. An alternative division of early Homo, based on a phenetic analysis of shape, suggests that one subgroup is primitive while the other has affinities with the “robust” australopithecines.