Preliminary investigation of the Matjhabeng, a Pliocene fossil locality in the Free State of South Africa

Abstract

The early Pliocene is a relatively poorly understood period in southern Africa. Fossil deposits such as Langebaanweg (c. 5.0 Ma) and Makapansgat (c. 2.5 Ma) have each produced large and well-documented faunal assemblages, and it is clear that a significant turnover of fauna occurred between the early and late Pliocene respectively. However, the temporal separation between Langebaanweg and Makapansgat represents a significant gap in our knowledge of faunal composition and evolution in the Pliocene of southern Africa. In 2007 we began a programme of excavation at an early Pliocene locality referred to as Matjhabeng (formerly Virginia) in the Free State of South Africa. With an estimated age of 4.0–3.5 Ma, this site represents a temporal and geographic intermediate between the better known sites to the north and south. It also represents the only well-documented, river-deposited Pliocene locality in the central interior of southern Africa. After three years of excavation, we have recovered a diverse fauna that includes fish, amphibians, reptiles, birds and mammals. Mammals range in size from rodents to mammoths, including an array of proboscideans, perissodactyls and artiodactyls, alongside rare carnivores. We report here on the macromammalian assemblage recovered to date. In total, we have recognized 29 taxa, including the oldest Ancylotherium and the oldest Megalotragus fossils in southern Africa. Some of the taxa from Matjhabeng are shared with Langebaanweg, and others with Makapansgat, confirming the intermediate status of this locality. Isotopic analysis reveals the earliest indication of extensive grasslands in South Africa, though these grasslands were part of an environmental mosaic that included significant woodland, and probable wetland, components.