1. Department of Pathology and Anatomical Sciences, University of Missouri, M263 Medical Sciences Building, Columbia, MO 65212, USA
2. Department of Anthropology, University of Arkansas, 330 Old Main, Fayetteville, AR 72701, USA
3. Department of Earth Sciences, National Museums of Kenya, P.O. Box 40658, Nairobi, Kenya
4. Turkana Basin Institute, Stony Brook University, Stony Brook, NY 11794, USA