1 Department of Anthropology, University of Nevada, Reno NV 89557; grscott@unr.edu.
2 Research Centre in Evolutionary Anthropology and Palaeoecology, School of Biological and Environmental Sciences, Liverpool John Moores University, Liverpool, United Kingdom L3 3AF.
3 Evolutionary Studies Institute, University of the Witwatersrand, Johannesburg, South Africa 2000.
4 Centre for Excellence in PaleoSciences, University of the Witwatersrand, Johannesburg, South Africa 2000.
5 National Research Center on Human Evolution, Burgos, Spain 09002.
6 Department of Anthropology, University College London, London, United Kingdom WC1E 6B5.