Study of hominoid evolution and human origin in East Africa

尽管它在类人猿和人类起源的进化中起着核心作用，但东非中新世中晚期的化石证据仍然很少。因此，这个时代被称为人类进化中“化石证据的巨大缺口”。该项目一直专注于这一尚不为人知的时期，并进行了多年的挖掘。2000年，按照最初研究建议的计划，在肯尼亚北部的纳乔拉山和桑布鲁山进行了挖掘和地质调查。研究结果如下：Nachola是一个化石非常丰富的地区，已经收集了大量的化石标本。我们在BG-K化石遗址进行了广泛的挖掘，在那里收集了大量的Nacholapithecus kerioi，新属和新种。我们收集了更多的化石标本，并移除了覆盖化石沉积物的部分风化的玄武岩层。工作区域南北长160米，东西长30米。玄武岩层厚5米。工人搬运的玄武岩砂石总量约为1万吨。至此，2001年野外季节的设置就完成了。新发现的化石标本超过50个。在Nakapoleterado河和Moru Abeyo地区进行了桑布鲁山的地质调查。对沉积物形成的时间和模式进行了地层学分析。在即将到来的季节，预计将从BG-K化石遗址出土大量的Nacholapithecus kerioi标本。一群个体可以为揭示这种化石类人猿的社会结构提供线索。

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.