2 - Origins and evolution of African Hominidae

Summary

INTRODUCTION

The African continent still preserves, in its equatorial reaches, mankind's closest living relatives, the chimpanzee (Pan) and gorilla (Gorilla) of the family Pongidae. In favourable parts of the continent there is a substantial fossil record for portions of the past 65 million years of geologic time, the Cenozoic Era. A diversity of primates are documented in the first (Palaeogene) part of that era, but in Africa only towards its end in the Oligocene Epoch. Though primitive still, some species are assigned to the Hominoidea, the primate superfamily which includes Hominidae and Pongidae, living and extinct. Early in the subsequent (Neogene) part of that era, the Miocene affords an abundance of primitive pongids, and in its mid to later parts there is even some suggestive evidence of more hominid-like creatures. Strangely, the fossil record of the African apes is thereafter essentially unknown.

This chapter attempts to set out in a general way the primary evidence for the evolution of Hominidae in Africa since the upper Miocene. The distribution of fossil localities yielding Cenozoic Hominidae on the continent is shown in the map at fig. 2.1. The temporal distributions of the most important fossil hominid occurrences are shown schematically in figs. 2.2 to 2.5. Their relationships are shown, also schematically, in the cladogram at fig. 2.13. The principal taxa of Hominidae most commonly recognized are duly considered but morphological details are generally avoided; the principal known features of each taxon are set out at length elsewhere (Howell 1978).