Dissertation Research: Taxonomy, Phylogeny, and Paleobiology of Late Paleocene Plesiadapidae (Mammalia, Primates): Implications for the Origin of Euprimates

该项目旨在确定一个古老灵长类动物（Plesiaadapidae）的祖先骨骼结构和生态位，该家族主要生活在 65-5500 万年前的古新世时期的北美和欧洲。现代灵长类动物，包括猿和人类、新旧世界猴子、狐猴、懒猴和眼镜猴，都通过一套独特的骨骼解剖特征来识别。 现代灵长类动物的共同祖先也具有这些特征，以及今天仅某些灵长类群体保留的某些其他特征。 关于这些“灵长类祖先特征”的适应性意义存在几种假设，这些假设可以通过化石记录进行最直接的测试。 这项对现代灵长类动物共同祖先化石近亲的 Plesiadapidae 的研究可以通过从非灵长类动物到现代灵长类动物的谱系变化历史来帮助阐明灵长类动物特征的获得模式。 因此，它测试了预测某些特征组同时出现（在同一化石中）的适应性假设。具体来说，PI正在收集数据，这些数据最终与最近有争议的假设有关，即在灵长类动物的生态史上，用指甲而不是爪子的对生大脚趾进行抓握的专门化先于获得视觉系统的某些特征（前向轨道）。 确定 Plesiadpidae 祖先的特征需要对物种水平的分类学进行修订，对群体成员之间的相互关系进行修订，并对这些动物的生态位进行全面的定量研究，包括饮食偏好和运动能力方面。试点数据表明，对 Plesiadpidae 成员之间的分类和关系模式知之甚少，但新的数据和分析将澄清谱系。 此外，新的骨骼材料表明，早期成员比后来的成员拥有更发达的抓足能力，从而发展出许多目前尚未记录的生态专业化。该项目更广泛的影响包括有可能澄清现代灵长类动物的身体特征首次出现的生态背景。 这些信息引起了身体和行为人类学家、新生儿学家、神经生物学家、更广泛的科学界甚至广大公众的兴趣，因为它提供了对灵长类动物和人类获得其独特特征的机制的解释。 这些解释影响相关领域所追求的研究问题的类型。此外，该项目还将创建一个大型数据档案，其形式包括（1）头骨的高分辨率 CT 扫描图像，以及（2）牙齿和颅后骨的激光扫描图像和数字照片，可用于其他与 plesiadapid 灵长类动物形态相关的定量研究。 这笔赠款还将为研究生提供培训。

This project seeks to determine the ancestral skeletal structure and ecological niche of a family of archaic primates, the Plesiadapidae, which lived primarily during the Paleocene epoch, 65-55 million years ago, in North America and Europe.Modern primates, including apes and humans, New and Old World monkeys, lemurs, lorises, and tarsiers, are recognized by a unique suite of anatomical features of the skeleton. The common ancestor of modern primates also had these features, as well as certain other features retained by only some primate groups today. Several hypotheses exist regarding the adaptive significance of these "ancestral primate features", which can be most directly tested using the fossil record. This study of the Plesiadapidae, a close fossil relative of the common ancestor of modern primates, can help illuminate the pattern of acquisition of primate features through the history of change in a lineage leading from non-primates to modern primates. It thereby tests adaptive hypotheses that predict simultaneous appearance (in the same fossil) of certain sets of features.Specifically, the PI is gathering data that ultimately bears on the recent controversial hypothesis that specializations for grasping with an opposable big toe, sporting a nail, instead of a claw, preceded acquisition of certain features of the visual system (forward facing orbits) in the ecological history of primates. Determination of characteristics of the ancestor of Plesiadapidae requires a revision of species level taxonomy, a revision of inter-relationships among members of the group, and a comprehensive quantitative study of the ecological niche of these animals, including aspects of dietary preference and locomotor repertoires.Pilot data suggest that the taxonomy and pattern of relationships among members of the Plesiadapidae are poorly understood, but that new data and analyses will clarify the genealogy. Further, new skeletal material suggests that early members had a better-developed grasping foot than later members, which went on to develop numerous, currently undocumented, ecological specializations.Broader impacts of this project include the potential to clarify the ecological context in which physical features characterizing modern primates first appeared. Such information is of interest to physical and behavioral anthropologists, neontologists, neurobiologists, the broader scientific community, and even the public in general because it provides an explanation of the mechanisms by which primates and humans acquired their distinctive features. These explanations affect the types of research questions that are pursued in related fields. Furthermore, this project will create a large data archive in the form of (1) high resolution CT-scan images of skulls, and (2) laser scan images and digital photographs of teeth and postcranial bones that can be used in other quantitative studies in which morphology of plesiadapid primates is relevant. The grant will also provide training for a graduate student.