Patterns of diversification in terrestrial vertebrate evolution

陆生脊椎动物进化的多样化模式

• 批准号: RGPIN-2020-04959
• 负责人: Reisz, Robert
• 金额: $ 2.91万
• 依托单位: University of Toronto
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2021
• 资助国家: 加拿大
• 起止时间: 2021-01-01 至 2022-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=740311
• 关键词: Patterns; diversification; terrestrial; vertebrate; evolution

The fossil record of vertebrates, with preservation of complex skeletons and teeth provides the best evidence of evolutionary dynamics across large temporal scales for investigating the mechanisms and conditions that led to the extant terrestrial communities, and modern ecosystems. The origin and initial stages of amniote evolution represent the start of a great chapter in earth's history, the conquest of land by vertebrates. In particular, shortly after their first appearance 316 Million years ago, we see rapid evolutionary radiations of reptiles and synapsids during the Late Carboniferous and early Permian. This time period is particularly important for studies of vertebrate evolution on land because evolutionary innovations initiated at this time form the foundations of extant communities and their squamate, chelonian, crocodilian, avian, and mammalian members, as well as those of Mesozoic communities dominated by reptiles like dinosaurs. Similarly, some clades of amphibians underwent rapid and sustained diversification during the Paleozoic as they evolved to a fully terrestrial lifestyle. Dissorophoids are significant and research worthy within this context because they coexisted with amniotes as terrestrial predators before giving rise to lissamphibians (extant amphibians - frogs, salamanders, and apodans). Long term studies of the anatomy, diversity, and evolutionary relationships of Paleozoic terrestrial tetrapods will continue to be part of this proposal because new discoveries have major impacts on our understanding of vertebrate evolution. In this proposal I will take a two-pronged approach. Firstly, I will expand my recent work on dental anatomy, development and replacement and propose to evaluate changes in both taxic and ecological diversity within a phylogenetic framework as reflected by the reconstructed feeding behaviour. I will examine morphological variation (disparity), including dental and mandibular diversity in comparative phylogenetic and temporal contexts in order to track the ecological diversification of early amniotes and coeval terrestrial tetrapods as they evolved to access formerly unoccupied ecospaces and novel food resources. Morphometric analyses of variation in tooth and jaw shape and size in successive Paleozoic communities will be organized into time bins that extend from the late Carboniferous (316 Ma) to the end of the early Permian (272 Ma). Secondly, this new approach will be incorporated with other skeletal variables, especially new neurocranial anatomy derived from multimodal CT data into comprehensive time calibrated phylogenetic analyses. The novel use of ecological and taxic diversity patterns within a phylogenetic framework represents one of the transformative ways in which we approach this important chapter in vertebrate evolution. These analyses will shed light for the first time on the community structure and evolution of tetrapods during the initial stages of terrestrial vertebrate evolution.

脊椎动物的化石记录保存了复杂的骨骼和牙齿，为研究导致现存陆地群落和现代生态系统的机制和条件提供了跨越大时间尺度的进化动力学的最佳证据。脊椎动物进化的起源和最初阶段代表了地球历史上一个伟大篇章的开始，脊椎动物征服土地。特别是，在3.16亿年前首次出现后不久，我们看到晚石炭纪和早二叠世期间爬行动物和联会动物的快速进化辐射。这一时期对陆地脊椎动物进化的研究特别重要，因为在这一时期开始的进化创新形成了现存群落及其有鳞目、龟类、鳄鱼类、鸟类和哺乳动物成员的基础，以及以恐龙等爬行动物为主的中生代群落的基础。同样，一些两栖动物的分支在古生代经历了快速和持续的多样化，因为它们进化到完全的陆地生活方式。在此背景下，Dissorophoids是重要的和值得研究的，因为它们在产生lissampibians（现存的两栖动物-青蛙，蝾螈和apodans）之前与陆地掠食者共存。对古生代陆生四足动物的解剖学、多样性和进化关系的长期研究将继续是这一提议的一部分，因为新的发现对我们理解脊椎动物进化有重大影响。在这项建议中，我将采取双管齐下的办法。首先，我将扩大我最近的工作牙齿解剖，发展和更换，并建议评估的类群和生态多样性的变化在系统发育框架内所反映的重建喂养行为。我将研究形态的变化（差距），包括牙齿和下颌骨的多样性比较系统发育和时间的背景下，以跟踪生态多样性的早期的古龙和同时代的陆地四足动物，因为他们进化到以前未占用的生态空间和新的食物资源。牙齿和颌骨的形状和大小在连续的古生代社区的变化的形态测量分析将组织到时间箱，从晚石炭世（316马）到早二叠世（272马）结束。其次，这种新的方法将与其他骨骼变量，特别是新的神经颅解剖来自多模态CT数据到全面的时间校准系统发育分析。在系统发育框架内，生态和分类多样性模式的新用途代表了我们接近脊椎动物进化这一重要篇章的变革性方式之一。这些分析将首次揭示陆生脊椎动物进化初期四足动物的群落结构和进化。