RUI: The Early Evolution of the Pholidota and a Reexamination of the Monophyly of the Cohort Edentata (Mammalia)

RUI：伞形纲的早期进化和无齿纲单系性的重新审视（哺乳动物）

• 批准号: 0107922
• 负责人: Timothy Gaudin
• 金额: $ 12.64万
• 依托单位: University of Tennessee Chattanooga
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2001
• 资助国家: 美国
• 起止时间: 2001-08-15 至 2005-07-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0107922&HistoricalAwards=false
• 关键词: RUI; Early; Evolution; Pholidota; Reexamination

The members of the mammalian orders Pholidota (the Old World pangolins, or scaly anteaters) and Xenarthra (the New World armadillos, anteaters and sloths and their extinct kin) are among the most unusual of all placental mammals. Despite the differences in anatomy, ecology and geographic distribution presented by these mammals, previous studies have suggested that these two orders share a close common ancestry, as evidenced by the reduction or elimination of their teeth and a handful of other detailed anatomical similarities. Unfortunately, the potential relationship of these two groups to one another or to other groups of placental mammals remains one of the least investigated portions of placental mammal phylogeny. The goal of the proposed study is twofold: (a) to support research at the National Museum of Natural History in Washington, D.C. including preparation, illustration and description of a complete skeleton of the fossil pangolin Patriomanis americanus.; and (b) to conduct an analysis of the phylogenetic relationships of the order Pholidota, including all seven living species as well as the three other well-known extinct pangolins, Eomanis and Necromanis, from the Eocene and Oligo-Miocene of Europe respectively, as well as an undescribed taxon from the Eocene of Mongolia. The results from this new phylogenetic study will be combined with the results of previous studies on the systematic relationships within the order Xenarthra to form the foundation of a broader study on the phylogeny of the Cohort Edentata, a group that ostensibly includes the pholidotans, xenarthrans and an extinct early Tertiary group of burrowing mammals, the Palaeanodonta. The proposed study will examine skeletal characteristics in representatives of each of the major extinct and living family level groupings within Pholidota, Xenarthra and Palaeanodonta. These characters will then be compared to the condition in a range of living and extinct placental and marsupial ingroup and outgroup taxa. This study will be the first comprehensive cladistic investigation of edentate relationships based on anatomical features. It will also be the only such study to incorporate all the major edentate lineages, as well as a broad sampling of other placental orders, including representatives of each of the major placental supraordinal groups identified by previous studies. The results of the proposed study will serve as an important groundwork for understanding the evolution of the various unusual anatomical and ecological specializations that characterize pholidotan and xenarthran mammals, the prevalence of convergent adaptations in these groups, and the biogeographic history that underlies their diversification. Furthermore, some previous work has suggested that some or all of these edentate groups diverged from other placental mammals at or near the base of the placental radiation. If this is indeed the case, an improvedunderstanding of edentate evolution may yield insight into the early biogeographic history and adaptive radiation of all placental mammals. One or more undergraduate students will be trained in various aspects of paleontological and systematics research.

哺乳动物的成员Pholidota（旧世界穿山甲，或有鳞食蚁兽）和Xenarthra（新世界犰狳，食蚁兽和树懒及其灭绝的亲属）是所有胎盘哺乳动物中最不寻常的。 尽管这些哺乳动物在解剖学、生态学和地理分布上存在差异，但以前的研究表明，这两个目有着密切的共同祖先，这一点可以从它们牙齿的减少或消失以及一些其他详细的解剖学相似性中得到证明。 不幸的是，这两个群体彼此之间或与其他胎盘哺乳动物群体之间的潜在关系仍然是胎盘哺乳动物胚胎发育研究中最少的部分之一。 这项拟议中的研究有两个目的：（a）支持华盛顿，华盛顿特区的国家自然历史博物馆的研究，包括准备、说明和描述美洲穿山甲化石的完整骨架。及（B）分析石仙桃目的系统发育关系，包括所有七个现存物种，以及分别来自欧洲始新世和渐新世-中新世的另外三种已知已灭绝的穿山甲（Eomanis和Necromanis），以及蒙古始新世的一个未描述分类群。 这项新的系统发育研究的结果将与以前对Xenarthra目内系统关系的研究结果相结合，以形成对无齿动物群（Cohort Edentata）的系统发育进行更广泛研究的基础，该群体表面上包括pholidotans，xenarthrans和已灭绝的早期第三纪穴居哺乳动物群Palaeanodonta。 拟议的研究将检查骨骼特征的代表，每个主要的灭绝和生活家庭水平分组内石仙桃，Xenarthra和Palaeanodonta。 然后将这些特征与一系列现存和灭绝的胎盘类和有袋类内群和外群类群的条件进行比较。 这项研究将是第一个全面的分支调查的缺齿动物的关系的基础上解剖特征。 这也将是唯一一项纳入所有主要缺齿动物谱系的研究，以及其他胎盘目的广泛抽样，包括先前研究确定的每个主要胎盘超序组的代表。拟议中的研究结果将作为一个重要的基础，了解各种不寻常的解剖和生态专业化的特点pholidotan和xenarthran哺乳动物，在这些群体中的趋同适应的流行，以及地理历史，其多样化的演变。此外，一些先前的工作表明，这些无齿动物的一些或全部在胎盘辐射的基部或附近与其他胎盘哺乳动物分化。 如果事实确实如此，对缺齿动物进化的进一步理解可能会使我们深入了解所有胎盘哺乳动物的早期胚胎发育史和适应性辐射。 一个或多个本科生将在古生物学和系统学研究的各个方面进行培训。