A Multi-Disciplinary Perspective on the Age of Australopithecus in Southern Africa

Abstract

This paper presents a review of, and new data concerning, the age of Australopithecus in southern Africa. Current dating suggests that Makapansgat Limeworks is the oldest hominin deposit in southern Africa, with Australopithecus africanus dating to between 3.0 and 2.6 Ma. The Taung Child A. africanus fossil from Taung is most likely penecontemporary with the Makapansgat material between 3.0 and 2.6 Ma. A. africanus from Sterkfontein Member 4 is estimated to date to between 2.6 and 2.0 Ma, with the Sts 5 specimen dating to around 2.0 Ma. The A. africanus deposits from Gladysvale are most likely contemporaneous with the Sterkfontein group with an age between 2.4 and 2.0 Ma. The potential second species of Australopithecus, StW 573 from the Silberberg Grotto at Sterkfontein, is most likely dated to between 2.6 and 2.2 Ma. As such, StW 573 is contemporary with A. africanus fossils from Member 4 and suggest that two contemporary Australopithecus species occurred at Sterkfontein between ~2.6 and 2.0 Ma. Based on the presence of Equus the A. africanus fossils from Jacovec Cavern also likely date to <2.4 Ma. The new Australopithecus sediba-bearing deposits of Malapa date to 1.98 Ma and suggests that three different species of Australopithecus occur in South Africa between 2.3 and 1.9 Ma. Given these dates, A. africanus represents the oldest southern African hominin species being found in two temporally distinct groups of sites, Makapansgat/Taung and Sterkfontein/Gladysvale, and A. sediba is the youngest species at ~1.98 Ma. However, if StW 53 is also Australopithecus, as some have suggested, then this genus survives to younger than 1.8 Ma in South Africa. Australopithecus thus lasted for a significant period of time in southern Africa after the genus is last seen in eastern Africa (Australopithecus garhi at ~2.5 Ma). This new dating indicates that the South African Australopithecus fossils are younger than previously suggested and are contemporary with the earliest suggested representatives of Homo (~2.3 Ma) and Paranthropus (2.7–2.5 Ma) in eastern Africa.