1. Evolutionary Studies Institute, University of the Witwatersrand, WITS 2050 Johannesburg, South Africa;
2. Department of Anthropology, University of Wisconsin–Madison, Madison, Wisconsin 53706, USA;
3. Department of Biology, Birmingham-Southern College, Birmingham, Alabama 35254, USA;
4. School of Geography, Archaeology and Environmental Studies, University of the Witwatersrand, WITS 2050 Johannesburg, South Africa;