Macroevolutionary Analyses of Cranial Morphology and Function in Mammals

哺乳动物包括5,400多个物种，并显示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与获取、消费和处理新食物资源的能力相关的结构进化的结果。然而，这一假设还没有在大多数哺乳动物群体中得到检验，因此哺乳动物多样性是如何产生的这个问题仍然是一个重要的、尚未回答的问题。这个项目将使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，以及咀嚼或咀嚼肌肉)，以在物种最丰富、生态最多样化的三种哺乳动物群体中测试这一假说：蝙蝠、食肉动物和灵长类动物。这项研究将产生关于咀嚼肌肉和100多个物种的三维头骨解剖的史无前例的定量数据集。研究人员将探索这些解剖和功能(内部)因素与外部因素(如食物特性和多样性)之间的联系，以此作为理解物种多样性模式的一种方式。通过这项工作，该项目将创建一个大型哺乳动物3D颅骨形态的公共数据库，培训不同的学生群体，通过公共博物馆展览传播结果，并在几名年轻研究人员之间建立跨学科合作。形态和功能适应是整个生命树生态多样化的重要驱动因素。在哺乳动物内部，人们假设许多辐射是由于形态和功能特征的进化而实现的，这些特征提供了进入新的饮食适应区的途径，但对于哺乳动物的广泛多样性，缺乏对这一假设的定量测试。这一差距的部分原因是广泛缺乏整合喂养装置的骨学和肌学成分的比较数据集。这些数据目前只存在于不到2%的哺乳动物分类群中，对于理解哺乳动物的咀嚼生理学和应用多样化分析是至关重要的，这些分析对比了哺乳动物辐射的内在和外在驱动因素的相对影响。这项拟议的工作将通过生成迄今为止关于哺乳动物摄食装置的三维形态、功能和性能的最大比较数据集，来测试关于生态多样性的宏观进化假说。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，在三个物种丰富且生态多样的哺乳动物支系(蝙蝠、食肉动物和灵长类)上产生这些数据。系统发育比较分析将被用来检验关于饮食选择制度对颅骨形态、功能和性能进化的影响及其与血统多样性的关联的假设。这项研究的生物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进食的生理学、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.