Study for the Tertiary Promates and their Palaeoenvironments in East Africa

本研究的目的是探讨人类起源的过程和机制。自1980年以来，在肯尼亚北部巴拉戈伊以西的桑布鲁山和纳乔拉地区进行了类人猿化石的挖掘和地质古生物学调查。该项目的主要成果是发现了一种大型人科动物（Samburu人科动物）和肯尼亚猿人，并分析了这些人科动物的古环境。在Nachola地区Aka-Aitepus组沉积物（12-15Ma）中发现了肯尼亚猿。巨大的犬齿否认了肯尼亚猿人是最早的人类。从木材化石（Croton）和爬行动物化石的共存来看，古人类生活的环境可能是潮湿的森林。Samburu类人猿是在namulungulle组（7-10Ma）沉积物中发现的。左上颌骨和上齿碎片的特征表明，这只人猿可能是原始人和非洲猿类的共同祖先。在同一沉积物中出土的两种河马表明，这种类人猿可能生活在开阔的林地和草地之间的环境中，气候相对干燥。对桑布鲁类人猿和肯尼亚猿人的进一步研究将有助于解决人科起源问题。因此，我们有必要继续在肯尼亚北部的桑布鲁山和纳乔拉地区进行发掘和调查。

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.