Doctoral Dissertation Improvement Grant: Origin and Early Evolutionary History of Primates

化石 plesiadapiforms（假定的早期灵长类动物）和其他密切相关的哺乳动物（灵长类动物、树鼩和飞狐猴）之间的进化关系已经争论了几十年。最近的几项分析表明，plesiadapiforms与现代灵长类动物关系最密切，因此对于检验有关灵长类动物起源和最早进化历史的假设至关重要。该项目的目的是澄清哪些解剖特征将灵长类动物与其他哺乳动物区分开来，并阐明某些现代灵长类动物特征在与非灵长类哺乳动物分化后进化的顺序。 该项目将分析 Micromomyidae 的古生物学和系统学；已知颅后动物的最原始的 plesiadapiforms 家族。对所有已知的小木鼠化石材料（包括四个未描述的骨骼）的功能分析将在新的系统发育树的背景下进行解释。将利用系统发育系统学的现代方法，包括形态学和分子分析相结合，以及形态学数据的贝叶斯方法。尽管这些技术在进化生物学的其他领域越来越受欢迎，但它们尚未用于评估灵长类动物及其近亲之间的关系。集成微型CT扫描的创新方法将用于定量比较小木鼠骨骼与密切相关的哺乳动物的骨骼，并重建最原始灵长类动物的位置行为和抓取能力的多样性。微型CT扫描还将用于量化牙冠尺寸，并确定原始灵长类动物的饮食习惯。这项研究将促进更好地了解人类与其他哺乳动物的分歧的第一步。本科生将接受数据收集所有领域的培训，所有数据将上传到在线数字档案。外展活动包括提议在耶鲁皮博迪博物馆举办关于灵长类动物起源的展览，以及在当地高中举办讲座。

Evolutionary relationships among fossil plesiadapiforms (putative early primates) and other closely related mammals (primates, treeshrews, and flying lemurs) have been debated for decades. Several recent analyses suggest that plesiadapiforms are most closely related to primates of modern aspect, and are therefore critical for testing hypotheses regarding the origin and earliest evolutionary history of primates. The aim of this project is to clarify which anatomical features separate primates from other mammals, and to elucidate the order in which certain modern primate features evolved following the divergence from non-primate mammals. This project will analyze the paleobiology and systematics of the Micromomyidae; the most primitive family of plesiadapiforms for which postcrania are known. Functional analyses of all known micromomyid fossil material, including four undescribed skeletons, will be interpreted in the context of a new phylogenetic tree. Modern methods in phylogenetic systematics will be utilized, including combined morphological and molecular analyses, and Bayesian methods for morphological data. Although these techniques are gaining popularity in other areas of evolutionary biology, they have not yet been used to assess relationships among primates and their close relatives. Innovative methods integrating micro CT scans will be used to quantitatively compare micromomyid skeletons to those of closely related mammals, and to reconstruct the diversity of positional behaviors and grasping abilities of the most primitive primates. Micro CT scans will also be used to quantify tooth crown dimensions, and determine the dietary habits of primitive primates.This research will promote a better understanding of the first clear step in the divergence of humans from other mammals. Undergraduate students will be trained in all areas of data collection, and all data will be uploaded to online digital archives. Outreach includes the proposal of an exhibit on primate origins at the Yale Peabody Museum, as well as lectures at local high schools.