Article Plio-Pleistocene Hyracoidea from Swartkrans Cave, South Africa

Abstract

Swartkrans Cave, an important Pleistocene hominid site in the Sterklontein valley, has yielded abundant fossil hyracoid remains. Two extinct taxa, Procavia antiqua and P. transvaalensis, have been previously reported to occur at the site in deposits postdating 1,8 million years before the present (B.P.). The extant taxon, P. capensis, has been reported in the most recent deposits, thought to include the Terminal Pleistocene. However, statistical analyses of teeth suggest that P. antiqua and P. capensis are conspecific. P. transvaalensis differs from P. capensis by being larger and more hypsodont. The coexistence of these taxa in palaeoenvironments of the Sterkfontein valley is attributed to dietary differences: P. transvaalensis being dependent primarily on grass foliage in grassland habitats, P. capensis being a generalist, feeding on a range of different kinds of vegetation in rocky habitats. Hypoconid-metaconid distances, previously used by Broom to distinguish taxa, are shown to be related to individual age. Crown height data of molars are used to generate age distributions, and incisors are used to obtain sex ratios, Predation on adults of P. transvaalensis, Irom populations associated with a sex ratio biased towards males. may have contributed to the decline in relative abundance and ultimate extinction of this species towards the end of the Pleistocene. Predators can have included leopards, black eagles and/or hominids.