Phenetic affinities among early Homo crania from East and South Africa

A quantitative analysis that employs randomization methods and distance statistics has been undertaken in an attempt to further clarify the phenetic and taxonomic affinities of Plio-Pleistocene Homo crania from eastern and southern Africa. Modern reference samples of Homo sapiens (n= 44), Pan troglodytes (n= 50) and Gorilla gorilla (n= 50), and three Paranthropus crania were employed in an assessment of the differences among the early Homo specimens. Crania attributed to Homo habilis sensu lato (OH 24, KNM-ER 1470, KNM-ER 1813, Stw 53 and SK 847) are clearly distinct from those assigned to Homo ergaster or early Homo erectus (KNM-ER 3733 and KNM-WT 15000). The crania attributed to H. habilis sensu lato form three rather distinct phenetic clusters. An orthognathic reconstruction of KNM-ER 1470 is clearly differentiated from the other four specimens principally by virtue of its size, whereas significant shape differences exist between the smaller specimens from eastern Africa (OH 24 and KNM-ER 1813) and those from South Africa (SK 847 and Stw 53). The level of taxonomic differentiation between these three clusters is difficult to assess on the basis of the data employed here, but these results lend support to arguments that KNM-ER 1470 should be attributed to a different species from OH 24 and KNM-ER 1813, and to suggestions that the South African specimens may represent a species of Homo that has not been sampled in eastern Africa. Furthermore, the present data indicate that gorillas do not comprise an appropriate group by which to gauge intraspecific cranial variability in early Homo.