[1] Univ Tubingen, DFG Ctr Adv Studies Words, Bones, Genes,Tools, Tubingen, Germany
[2] French Ctr Ethiopian Studies, Addis Ababa, Ethiopia
[3] CNRS UMR 5276, Lab Geol, ENS, Lyon, France
[4] Rift Valley Res Serv, Addis Ababa, Ethiopia
[5] Six 6 Salako Way, Santa Fe, NM 87506 USA
[6] Miami Univ, Dept Geol & Environm Earth Sci, Oxford, OH 45056 USA
[7] US Geol Survey, Denver Fed Ctr, Denver, CO USA
[8] Univ Calif Berkeley, Berkeley Geochronol Ctr, Berkeley, CA 94720 USA
[9] Univ Calif Berkeley, Dept Earth & Planetary Sci, Berkeley, CA 94720 USA
[10] Univ Calif Berkeley, Human Evolut Res Ctr, Berkeley, CA 94720 USA
[11] Univ Calif Berkeley, Dept Integrat Biol, Berkeley, CA 94720 USA