Macroevolutionary Analyses of Cranial Morphology and Function in Mammals

哺乳动物包括5,400多个物种，并表现出非凡的解剖和饮食多样性。据推测，哺乳动物物种的巨大多样性是由于与获取、消费和加工新食物资源的能力相关的结构的进化。然而，这一假设尚未在大多数哺乳动物群体中得到验证，因此哺乳动物多样性是如何产生的问题仍然是一个重要的、悬而未决的问题。该项目将采用一套现代工具来研究与进食相关的解剖学和物理力量（如头骨或颅骨解剖学，咀嚼或咀嚼肌），以在三个物种最丰富和生态多样的哺乳动物群体中测试这一假设：蝙蝠，食肉动物和灵长类动物。这项研究将产生前所未有的关于咀嚼肌和100多个物种的三维头骨解剖的定量数据集。研究人员将探索这些解剖和功能（内部）因素与外部因素（如食物特征和多样性）之间的联系，以了解物种多样化的模式。通过这项工作，该项目将创建一个大型的哺乳动物3D颅骨形态公共数据库，培训一个多元化的学生群体，通过公共博物馆展览传播成果，并在几个年轻的研究人员之间建立跨学科的合作。形态和功能适应是整个生命之树生态多样化的重要驱动力。在哺乳动物中，人们假设许多辐射是通过形态和功能特征的进化实现的，这些特征提供了进入新的饮食适应区的途径，但缺乏对哺乳动物广泛多样性的定量测试。这一差距的部分根源是广泛缺乏比较数据集，整合了骨骼和骨骼肌组成部分的喂养装置。这些数据，目前存在的哺乳动物类群的不到2%，是迫切需要的哺乳动物咀嚼生理学的理解和多样化的分析，对比哺乳动物辐射的内在与外在驱动程序的相对影响的应用。拟议的工作将通过生成迄今为止关于哺乳动物摄食器官的三维形态、功能和性能的最大比较数据集，来测试关于生态多样化的宏观进化假设。该团队将结合微型计算机断层扫描，大体解剖，几何形态测量分析和生物力学建模，以产生三个物种丰富和生态多样的哺乳动物分支（蝙蝠，食肉动物和灵长类动物）的这些数据。系统发育比较分析将被用来测试的饮食选择制度的影响，颅形态，功能和性能的演变，以及它们与血统多样化的关联的假设。该研究的有机体方面将阐明具有广泛科学意义的哺乳动物群体的生物力学和生态形态多样性。这项研究将有助于阐明这些群体多样化的潜在驱动因素，同时为进一步研究哺乳动物摄食的生理学，生物力学和进化奠定基础。

Mammals comprise over 5,400 species, and exhibit extraordinary anatomical and dietary diversity. It is hypothesized that the great diversity of mammalian species resulted from the evolution of structures associated with an ability to access, consume and process new food resources. However, this hypothesis has not been tested for the majority of mammal groups, and therefore the question of how mammalian diversity arose remains an important, unanswered one. This project will employ a suite of modern tools in the study of anatomy and physical forces associated with feeding (such as skull or cranial anatomy, and chewing or masticatory muscles) to test this hypothesis in three of the most species-rich and ecologically diverse mammal groups: bats, carnivores and primates. The research will generate unprecedented quantitative datasets on the masticatory muscles and the three-dimensional skull anatomy of over 100 species. The researchers will explore the links between these anatomical and functional (internal) factors with external factors (such as food characteristics and diversity) as a way to understand patterns of species diversification. Through this work, the project will create a large public database of mammal 3D cranial morphology, train a diverse group of students, disseminate results through a public museum exhibit, and establish cross-disciplinary collaborations among several young investigators.Morphological and functional adaptations are important drivers of ecological diversification across the Tree of Life. Within mammals, it is hypothesized that many radiations were enabled by the evolution of morphological and functional traits that provided access to new dietary adaptive zones, but quantitative tests of this hypothesis are lacking for the broad diversity of mammals. This gap is partly rooted on the extensive lack of comparative datasets that integrate both the osteological and myological components of the feeding apparatus. These data, which currently exist for less than 2% of mammalian taxa, are critically needed both for an understanding of mammalian masticatory physiology and for the application of diversification analyses that contrast the relative influences of intrinsic versus extrinsic drivers of mammalian radiation. The proposed work will test macroevolutionary hypotheses about ecological diversification by generating the largest comparative datasets to date on the three-dimensional morphology, function and performance of the mammalian feeding apparatus. The team will couple micro-Computed Tomography, gross dissections, geometric morphometric analyses and biomechanical modeling to produce these data across three species-rich and ecologically diverse mammal clades (bats, carnivorans and primates). Phylogenetic comparative analyses will be used to test hypotheses about the influence of dietary selective regimes on the evolution of cranial morphology, function and performance, and their association with lineage diversification. The organismal aspect of the research will illuminate the biomechanics and ecomorphological diversity in mammal groups that are of broad scientific interest. This study will help elucidate the potential drivers of diversification in these groups while creating a foundation for further research on the physiology, biomechanics and evolution of mammal feeding.