Late Pliocene fossiliferous sedimentary record and the environmental context of early Homo from Afar, Ethiopia

Abstract : Sedimentary basins in eastern Africa preserve a record of continental rifting and contain important fossil assemblages for interpreting hominin evolution. However, the record of hominin evolution between 3 and 2.5 million years ago (Ma) is poorly documented in surface outcrops, particularly in Afar, Ethiopia. Here we present the discovery of 2.84-2.58 Ma fossil and hominin-bearing sediments in the Ledi-Geraru research area that have produced the earliest record of the genus Homo. Vertebrate fossils record a faunal turnover indicative of more open and probable arid habitats than those reconstructed earlier in this region, in broad agreement with hypotheses addressing the role of environmental forcing in hominin evolution at this time. Geological analyses constrain depositional and structural models of the Afar and date the LD 350-1 Homo mandible to 2.80-2.75 Ma.