Affiliation: | a Human Origins Program, Department of Anthropology, National Museum of Natural History, Smithsonian Institution, PO Box 37012, MRC 112, Washington DC, 20013-7012, USA b Department of Anthropology, Harvard University, Cambridge MA, 02138, USA c Department of Mineral Sciences, National Museum of Natural History, Smithsonian Institution, PO Box 37012, MRC 119, Washington DC, 20013-7012, USA |