7. Comparability of fossil data and its significance for the interpretation of hominin environments A case study in the lower Omo Valley, Ethiopia Z. ALEMSEGED Department of Human Evolution Max Planek Institute for Evolutionary Anthropology Deutseher Platz, 6, 04103 Leipzig, Germany zeray@eva.mpg.de R. BOBE Department of Anthropology The University of Georgia Athens, GA 30602, USA renebobe@uga.edu D.GERAADS UPR 2147 CNRS-44 rue de I'Amiral Mouehez 75014 Paris, France dgeraads@ivry.enrsfr Keywords: Human evolution, paleoenvironments, Plio-Pleistocene, Shungura Fonnation, fossil databases Abstract Unraveling the context in which the evolution and diversification of early hominins occurred has become one of the core and highly debated subjects in paleoanthropology. Over the past three decades substantial progress has been made due to the proliferation of fieldwork and a consequently expanding fossil record, and development of new methods of analysis. The present study uses data of fossil mammals from the Shungura Fonnation of Ethiopia, with specimens collected semi-independently by French and American research teams who worked in the southern and northern parts of the Shungura area respectively. We compare these two samples in tenns of collection meth- ods, taxonomy, taphonomy, and local environmental differences. The following results were obtained: Cl) No major taphonomic differences were observed between the two collections. The effect of a major taphonomic shift that occurred in the middle of Member G (G-13) is observed in both samples and is caused by the important change in the depositional environment from fluvial to lacustrine conditions. (2) The French team collected more specimens than the American team, in part because it had a larger area of exposures, and it spent two extra seasons in the field. Additionally, the French team collected more large-sized taxa including their postcranial elements, while the American team recovered a restricted set of postcranial bones. In contrast, the American team collected more primates and carnivores than the French team. (3) Despite these differences, comparable taxonomic composition and number of species are observed in both collections. (4) A study of changes in relative abundance in bovid tribes indicates that similar patterns of variation through time are observed in both samples. This is considered to be evidence for the prevalence of generally similar habitats (and habitat change through time) in the north and 159 R. Bobe, Z. Alemseged, andAX. Behrensmeyer (eds.) Hominin Environments in the EastAfrican Pliocene: A n Assessment of the Faunal Evidence, 159-181. © 2007 Springer.