[1] Univ Cape Town, Dept Archaeol, ZA-7701 Rondebosch, South Africa
[2] Rutgers State Univ, Dept Anthropol, New Brunswick, NJ 08901 USA
[3] Johns Hopkins Univ, Dept Earth & Planetary Sci, Baltimore, MD 21218 USA
[4] Univ New S Wales, Univ New S Wales Archaeomagnetism Lab, Sch Med Sci, Sydney, NSW 2052, Australia
[5] Univ Witwatersrand, Bernard Price Inst Palaeontol, ZA-2050 Johannesburg, South Africa
[6] Liverpool John Moores Univ, Sch Nat Sci & Psychol, Res Ctr Evolutionary Anthropol & Palaeoecol, Liverpool L3 3AF, Merseyside, England
[7] George Washington Univ, Dept Anthropol, Ctr Adv Study Hominid Paleobiol, Washington, DC 20052 USA
[8] Smithsonian Inst, Natl Museum Nat Hist, Human Origins Program, Washington, DC 20052 USA
[9] Natl Museums Kenya, Div Sites & Monuments, Nairobi 4065800100, Kenya