Study of hominoid evolution and human origin in East Africa

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Despite its central role for the evolution of hominoids and human origins, fossil evidences from middle-to-late Miocene from east Africa are still scarce. Hence, this age is colled the 'great gap of fossil evidence" in human evolution. This project has focused on this yet-to-known tie period and conducted excavations for years. In 2000, excavations and geological surveys have been conducted in Nachola and Samburu Hills, northern Kenya as had been planned in the initial research proposal. Results of the research are as follows.Nachola is a very fossil rich area and abundant fossil specimens have been collected. We did and extensive excavation at the BG-K fossil Site, where the bulk of hypodigm of Nacholapithecus kerioi, new genus and species has been collected. We collected additional fossil specimens and removed a partly weathered basalt layer which covers the fossil bearing sediments. The work area is 160m north to south and 30m east to west. The layer of basalt is 5m in thickness. The total amount of the basaltic sand and rock taken by labors is about 10,000 tons. The setting for the 2001 field season is thus completed. Number of the new fossil specimens exceeded 50.Geological survey in Samburu Hills has been conducted at river Nakapoleterado and Moru Abeyo areas. Taphonomic analyses have been done to investigate the duration and the pattern of the sediment formation.In the forthcoming seasons, it is expected that numerous Nacholapithecus kerioi specimens will be unearthed from the BG-K Fossil Site. One troop of individuals could give a clue to reveal the social structure of this fossil hominoid.