Paleontology and Primate Evolution in the Late Oligocene of Kenya

肯尼亚渐新世晚期的古生物学和灵长类动物进化

• 批准号: 0749805
• 负责人: David Rasmussen
• 金额: $ 23.99万
• 依托单位: Washington University
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2008
• 资助国家: 美国
• 起止时间: 2008-04-15 至 2013-03-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0749805&HistoricalAwards=false
• 关键词: Paleontology; Primate; Evolution; Late; Oligocene

One of the great gaps in the fossil record of the primate group containing Old World monkeys, apes and humans (catarrhines) has been the one spanning the interval from about 30 to 20 million years ago in Africa. This gap has now been filled by two sites of Late Oligocene age (approximately 24-27 million years old) in northwestern Kenya, both of which yielded new primate fossils during preliminary fieldwork in June, 2007. The current research is designed to find more primate fossils representing more complete skeletal remains from the new research areas, to put the primates into a solid framework of geological age and paleoenvironment, and to conduct phylogenetic and paleobiological analyses of them. Field camps will be established at the sites of Nakwai and Losodok, and research will be conducted with an interdisciplinary crew of anthropologists, paleontologists, geologists, including students, to recover primate fossils, other mammals, reptiles and birds, fossils of paleoenvironentally important plants, and rock samples for radiometric, paleomagnetic, and geo-isotopic studies. Together, analyses of these data will document patterns of primate evolution and paleoenvironment during the Late Oligocene of Kenya. This work will be integrated into existing knowledge of the important basal catarrhines of the early Oligocene and the great radiation of apes in the early Miocene, in order to better understand the evolutionary transition from primitive, early catarrhines to the earliest large-bodied apes of the superfamily Hominoidea. Several issues of theoretical importance will be addressed. Some issues center around taxonomic assessments of Late Oligocene catarrhines: were true hominoids (members of the group containing only apes and humans) present at this time, or are the fossil ape-like primates precursors, or lateral relatives, of true hominoids? Had the evolutionary split between Old World monkeys and apes occurred by this time, as predicted by the latest molecular clocks? Other issues of theoretical importance center around the adaptations of these early ape-like primates, and the sequence in which they acquired ape-like traits, such as skeletal adaptations for their characteristic climbing movements, dental adaptations for frugivorous diets, and cranial adaptations associated with increasing brain size. The Late Oligocene is the period in which Africa, previously an island continent, was beginning to dock with the northern continents, and there is considerable theoretical interest in whether this geographic event was associated with African climatic change, shifts in environment or ecology, or changes in animal communities. Kenyan students and museum staff will be participate in this project, and many of the key analyses and laboratory procedures will be conducted with Kenyan colleagues, providing new opportunities and training for Kenyan paleontologists.

在包含旧大陆猴、猿和人类（卡他鼻类）的灵长类动物群化石记录中，有一个巨大的空白，那就是非洲大约3000万至2000万年前的化石记录。 这一空白现在已经被肯尼亚西北部的两个渐新世晚期（大约2400 - 2700万年）的遗址所填补，这两个遗址在2007年6月的初步野外工作中都发现了新的灵长类化石。当前的研究旨在从新的研究领域寻找更多代表更完整骨骼遗骸的灵长类动物化石，将灵长类动物置于坚实的地质时代和古环境框架中，并对其进行系统发育和古生物学分析。 将在Nakwai和Losodok遗址建立野外营地，并与包括学生在内的人类学家、古生物学家、地质学家组成的跨学科团队进行研究，以恢复灵长类动物化石、其他哺乳动物、爬行动物和鸟类、古生物学重要植物化石以及用于放射性、古地磁和地质同位素研究的岩石样本。 总之，这些数据的分析将记录在肯尼亚晚渐新世的灵长类动物进化和古环境的模式。 这项工作将被整合到现有的知识的重要基础catarrhines的早渐新世和大辐射的猿在中新世早期，为了更好地了解进化过渡，从原始的，早期catarrhines最早的大型体猿的超科Hominoidea。 将讨论几个具有理论意义的问题。一些问题围绕着渐新世晚期卡他类的分类学评估：真正的人科动物（只包括猿和人类的群体成员）是否存在于这个时候，或者化石类猿灵长类动物的前体，或者真正的人科动物的旁系亲属？ 正如最新的分子钟所预测的那样，旧大陆的猴子和猿类之间的进化分裂是否发生在这个时候？ 其他重要的理论问题围绕着这些早期类猿灵长类动物的适应性，以及它们获得类猿特征的顺序，例如骨骼适应其特有的攀爬运动，牙齿适应食果饮食，以及与大脑大小增加相关的颅骨适应。 渐新世晚期是非洲开始与北方大陆对接的时期，这一地理事件是否与非洲气候变化、环境或生态变化或动物群落变化有关，有相当大的理论兴趣。 肯尼亚学生和博物馆工作人员将参与该项目，许多关键分析和实验室程序将与肯尼亚同事一起进行，为肯尼亚古生物学家提供新的机会和培训。