Study for the Tertiary Promates and their Palaeoenvironments in East Africa

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The purpose of this research is to approach to a process and a mechanism of the origin of hominds. Since 1980,excavations of hominoid fossils and geological and palaeontological surveys has been conducted in the Samburu Hills and Nachola region, west of Baragoi, northern Kenya. The major results of the project are discoveries of a large hominoid (Samburu hominoid) and Kenyapichecus and an analysis of the palaeo-environments regarding those hominoids.Kenyapithecus has been uncovered in the sediments (12-15Ma) of Aka-Aitepus Formation of the Nachola area. The huge canine tooth denies that Kenyapithecus is the earliest hominid. By the coexistence of the fossilized wood(Croton) and reptile fossils, the environment in which the hominoid lived has been suggested to be a humid forest. The Samburu hominoid was found from the sediment(7-10Ma) of Namulungule Formation. A characteristics of the fragment of left maxilla and upper teeth suggest the hominoid might have been a common ancestor of hominids and living African apes. Two Kinds of Hipparions unearthed in the same sediment suggest that the hominoid might have lived in the environment between open woodland and grassland , with relatively dry climate.It is highly expecxted that further investigations of Samburu hominoid and Kenyapithecus may contribute to approach to the problems of hominid origin. Therefore, it is very necessary for us to continue excavations and surveys in the Samburu Hills and Nachola region, northern Kenya.