Macroevolutionary Analyses of Cranial Morphology and Function in Mammals

哺乳动物有5400多种，在解剖结构和饮食结构上表现出非凡的多样性。据推测，哺乳动物物种的巨大多样性源于与获取、消耗和加工新食物资源的能力相关的结构的进化。然而，这一假设还没有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、没有答案的问题。该项目将采用一套现代工具来研究与进食有关的解剖学和物理力（如头骨或颅骨解剖，咀嚼或咀嚼肌肉），以三种物种最丰富、生态最多样化的哺乳动物群体：蝙蝠、食肉动物和灵长类动物来验证这一假设。这项研究将为100多个物种的咀嚼肌肉和三维颅骨解剖提供前所未有的定量数据集。研究人员将探索这些解剖学和功能（内部）因素与外部因素（如食物特征和多样性）之间的联系，作为了解物种多样化模式的一种方式。通过这项工作，该项目将建立一个大型的哺乳动物3D颅骨形态学公共数据库，培养多样化的学生群体，通过公共博物馆展览传播结果，并在几位年轻研究者之间建立跨学科合作。形态和功能适应是生命之树生态多样化的重要驱动力。在哺乳动物中，有一种假设认为，许多辐射是由形态和功能特征的进化造成的，这些特征为进入新的饮食适应区提供了途径，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。造成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，对于理解哺乳动物咀嚼生理学和应用多样化分析（对比哺乳动物辐射的内在和外在驱动因素的相对影响）都是非常需要的。拟议的工作将通过产生迄今为止最大的关于哺乳动物喂养装置的三维形态、功能和性能的比较数据集来测试关于生态多样化的宏观进化假设。该团队将结合微观计算机断层扫描、大体解剖、几何形态分析和生物力学建模，以产生三种物种丰富且生态多样化的哺乳动物分支（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用于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的假设，以及它们与谱系多样化的关系。该研究的有机方面将阐明具有广泛科学兴趣的哺乳动物群体的生物力学和生态形态学多样性。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、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.