Rich source of fossils found in Free State

  • July 07, 2009

A riverbed on a farm in the Free State is the site of a ground-breaking fossil discovery. Several hundred animal fossils between 3.5-million and 4-million years old have been discovered on the site so far.

The site was discovered in 1955 by railway workers working on the train tracks for the gold mines. The workers discovered several mammoth fossils, including a near-complete tusk. Excavation only started 52 years later in 2007, leading to the discoveries.

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Excavation on the site.

Palaeontologist Darryl de Ruiter, an associate professor in the Department of Anthropology at Texas A&M University and Research Associate of the Institute for Human Evolution at the University of the Witwatersrand, explains that the find is the only one of its kind that survives in Southern Africa. “It falls in a particular time gap from which we have little fossil information in Southern Africa,” says de Ruiter.

The fossils are from the Pliocene epoch, which lasted from about 5.3-million years ago to about 2.6-million years ago, though precious few fossil localities dating to this exact time period are known in the region. “These fossils tend to be heavily fragmented, though some are very well preserved indeed,” says de Ruiter.

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Palaeontologists working on the Free State site.

Previously there were three major sites for this era in South Africa that palaeontologists drew information from, Makapansgat in the Limpopo province, Sterkfontein in the Cradle of Humankind World Heritage Site of Gauteng, and Langebaanweg in the Western Cape. With the information gathered on this Free State site, light will be shed on previously unanswered questions.

De Ruiter explains that the discovery of the Free State site “will provide some insight” into the environmental and faunal changes that occurred between the time of Langebaanweg, which is populated mostly by extinct species, and the time of Makapansgat and Sterkfontein, when species that are still around today began to appear in South Africa.

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A Mammuthus subplanifrons fossil.

Among the species found so far are Mammuthus subplanifrons (the earliest ancestor of modern elephants), Megalotragus (an ancestor of the wildebeest), extinct 3-toed horses, spring hares, snakes, waterbirds and fish. Also among the finds is Ancylotherium, a now-extinct taxon, which is related to the rhino. The most recent discovery is a crocodile, an animal with very particular habitat and temperature requirements.

While the excavation will take decades to complete, the finds so far show that there will be a lot of material found for the Pliocene epoch. As de Ruiter explains, “Every time we excavate there is a new discovery.”

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