Function, ecology and macroevolution of the mammalian masticatory system

背景：哺乳动物的咀嚼器官是理解外部生态和环境因素如何与解剖学和生理学相互作用以形成表型多样性的模型系统。然而，大多数研究都集中在骨形态的宏观进化和生态模式上。相对较少的研究同时评估了肌肉形态和功能的差异和收敛模式，从而限制了我们对咀嚼系统适应和约束的理解。目的：本项目的目的是对哺乳动物咀嚼系统中的硬（骨）和软组织（肌肉）进化进行综合分析，以确定这些组织在营养生态学进化转变中的适应性变化的相对性质和时间。因此，我们的具体目标是：OBJ1：确定在分类学和生态学上多样化的现存和灭绝哺乳动物的头骨形状进化模式。OBJ2：确定现存哺乳动物肌肉进化模式及其与生态多样性的关系。OBJ3：结合obj1和obj2的数据，生成已灭绝哺乳动物谱系肌肉进化的预测，记录营养生态学的进化转变。OBJ4：将由生物力学模型产生的咀嚼系统力学性能或适应性指标预测映射到进化景观上，以分析哺乳动物咀嚼系统形态、功能和生态多样性之间的关系。新颖性：现有的硬组织和软组织进化的综合研究仅限于特定的亚群，具有有限的分类和生态广度。我们将首次将尖端生物力学技术与进化景观分析方法相结合，利用这一理解上的差距。及时性：贝茨和考克斯最近的两项研究表明，当前功能形态学的宏观进化研究存在根本性的局限性。贝茨和考克斯已经收集了软组织数据，戈斯瓦米则收集了支撑这项研究的CT数据集。哺乳动物的咀嚼器官是理解外部生态和环境因素如何与解剖学和生理学相互作用以形成表型多样性的模型系统。然而，大多数研究都集中在骨形态的宏观进化和生态模式上。相对较少的研究同时评估了肌肉形态和功能的差异和收敛模式，从而限制了我们对咀嚼系统适应和约束的理解。该项目的目的是对哺乳动物咀嚼系统中的硬（骨）和软组织（肌肉）进化进行综合分析，以确定这些组织在营养生态学进化转变中的适应性变化的相对性质和时间。因此，我们的具体目标是：OBJ1：确定在分类学和生态学上多样化的现存和灭绝哺乳动物的头骨形状进化模式。OBJ2：确定现存哺乳动物肌肉进化模式及其与生态多样性的关系。OBJ3：结合obj1和obj2的数据，生成已灭绝哺乳动物谱系肌肉进化的预测，记录营养生态学的进化转变。OBJ4：将由生物力学模型产生的咀嚼系统的机械性能或适应性指标预测映射到“进化景观”上，以分析哺乳动物咀嚼系统形态、功能和生态多样性之间的关系。现有的硬组织和软组织进化的综合研究仅限于特定的亚群，具有有限的分类和生态广度。我们将首次将尖端生物力学技术与“进化景观分析”方法相结合，利用这一理解上的差距。

Background: The masticatory apparatus of mammals is a model system for understanding how extrinsic ecological and environmental factors interact with anatomy and physiology to shape phenotypic diversity. However, most studies have focused on macroevolutionary and ecological patterns in bony morphology. Relatively few studies have simultaneously assessed patterns of disparity and convergence in muscle morphology and function, thereby limiting our understanding of adaptations and constraints in the masticatory system.Objectives: The aim of this project is to carry out an integrated analysis of hard (bone) and soft tissue (muscle) evolution in the mammalian masticatory system to determine the relative nature and timing of adaptive changes in these tissues across evolutionary shifts in trophic ecology. Our specific objectives are therefore to:OBJ1: Determine patterns of skull shape evolution across a taxonomically and ecologically diverse range of extant and extinct mammals.OBJ2: Determine patterns of muscle evolution and their correlation with ecological diversity in extant mammals.OBJ3: Combine data from OBJ1&2 to generate predictions of muscle evolution in lineages of extinct mammals that record evolutionary shifts in trophic ecology.OBJ4: Map predictions of mechanical performance or fitness metrics for the masticatory system generated from biomechanical models on to an evolutionary landscape to analyse the relationship between morphological, functional and ecological diversity in the mammalian masticatory system.Novelty: Existing integrated studies of hard and soft tissue evolution are restricted to specific subgroups with limited taxonomic and ecological breadth. We will exploit this gap in understanding by combining cutting-edge biomechanical techniques with evolutionary landscape analysis approach for the first time.Timeliness: The works follows two recent studies by Bates and Cox that demonstrate fundamental limitations in current macroevolutionary studies of functional morphology. Bates/Cox have already assembled soft tissue data and Goswami the CT data sets that will underpin the study.The masticatory apparatus of mammals is a model system for understanding how extrinsic ecological and environmental factors interact with anatomy and physiology to shape phenotypic diversity. However, most studies have focused on macroevolutionary and ecological patterns in bony morphology. Relatively few studies have simultaneously assessed patterns of disparity and convergence in muscle morphology and function, thereby limiting our understanding of adaptations and constraints in the masticatory system.The aim of this project is to carry out an integrated analysis of hard (bone) and soft tissue (muscle) evolution in the mammalian masticatory system to determine the relative nature and timing of adaptive changes in these tissues across evolutionary shifts in trophic ecology. Our specific objectives are therefore to:OBJ1: Determine patterns of skull shape evolution across a taxonomically and ecologically diverse range of extant and extinct mammals.OBJ2: Determine patterns of muscle evolution and their correlation with ecological diversity in extant mammals.OBJ3: Combine data from OBJ1&2 to generate predictions of muscle evolution in lineages of extinct mammals that record evolutionary shifts in trophic ecology.OBJ4: Map predictions of mechanical performance or fitness metrics for the masticatory system generated from biomechanical models on to an 'evolutionary landscape' to analyse the relationship between morphological, functional and ecological diversity in the mammalian masticatory system.Existing integrated studies of hard and soft tissue evolution are restricted to specific subgroups with limited taxonomic and ecological breadth. We will exploit this gap in understanding by combining cutting-edge biomechanical techniques with 'evolutionary landscape analysis' approach for the first time.