Insights into the Middle Pleistocene fauna of South Africa: Zooarchaeology, stable isotopes and dating of Pniel 6

The Florisian Land Mammal Age (FLMA; 773-12 ka) is characterised by specialist, often extinct, grazing as well as wetland species, many of which are no longer present in the southern African interior. Middle Pleistocene FLMA faunal assemblages are rare, particularly those associated with artefacts, limiting reconstruction of environmental conditions and hominin subsistence strategies. One exception is the faunal assemblages of Pniel 6 on the Vaal River, which are associated with Fauresmith lithics. Here, we present a comprehensive faunal analysis including stable isotope measurements and intracrystalline protein diagenesis (IcPD) analysis from several excavations since the 1980s. Twenty-one animal species were identified, with size class III bovids and typical FLMA species dominating. The results suggest a rich grassland environment supported by considerable water components. While most of the assemblage exhibits signs of a natural death assemblage, a few taphonomic modifications may indicate a human factor. Two distinct IcPD data clusters provide relative age estimates, suggesting that the teeth do not represent a single short depositional event. All results support the interpretation of Pniel 6 as a series of distinctive archaeological accumulations of human origin during the Middle Pleistocene, with a minor component of younger material mixed up close to the modern surface.