Middle Miocene hominoid Nacholapithecus and hominoid evolution

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Human origin is an extension of evolutions of the middle so Miocene hominoids. Elucidating the evolutional processes of the Miocene hominoids is thus essential to understand the mechanism of the human origin. In this study, we have excavated e Site BG-K in Nachola, northern Kenya, whore many hominoid fossils wan empirically expected to be found, and conducted accompanying geological anti palaeontological surveys.Basaltic lava bed overlying the fossil containing sediments was removed at BG-K and we excavated 632m^2 in the year 2001, and 824m^2 in 2002. We firstly excavated relatively soft, 2m deep silt layer, and then hard, 20cm thick shale layer below the silt layer. The latter contained more fossils bat it is so hard that we had to collect anti bring all blocks containing fossils back to Kenya National Museum in Nairobi foes removal of matrix by skillful technicians.As a consequence, we collected more than 500 fossil specimens, including skulls, of the 15 million year old large homino … More id, Nacholapithecus. Morphological features of the fossils showed that is was not so differentiated as the 17 million year old Miocene hominoid, Afropithecus, suggesting that Nacholapithecus a common ancestor of later hominoid and human clades. Its locomotor behavior was also considered to be derived towards the extant hominoids. Development of forelimb was more prominent in Nacholapithecus thus in the preceding Miocene hominoid, Proconsul.Three fifth of the excavation at the Site BG-K has been unfinished. We will complete the excavation and detailed analyses of the specimens and plan to publish a monograph on Nacholapithecus in near future. There is no other group in the world who excavated fossils of a single species as abundantly as our group did. Moreover, our specimens include its whole skeleton and ace generally in excellent condition. Therefore, we will be able to thaw the entire picture of Nacholapithecus, a typical middle Miocene hominoid. Our achievements will be highly appraised internationally. Less