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: 2020
• 资助国家: 加拿大
• 起止时间: 2020-01-01 至 2021-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=717051
• 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.

保存有复杂骨骼和牙齿的脊椎动物化石记录为研究现存陆地群落和现代生态系统的机制和条件提供了大时间尺度进化动态的最佳证据。羊膜动物进化的起源和初始阶段代表了地球历史上一个伟大篇章的开始，即脊椎动物征服土地。特别是，在 3.16 亿年前首次出现后不久，我们在石炭纪晚期和二叠纪早期看到了爬行动物和合弓动物的快速进化辐射。这一时期对于陆地脊椎动物进化的研究尤为重要，因为此时发起的进化创新形成了现存群落及其有鳞动物、龟类、鳄鱼类、鸟类和哺乳动物成员，以及以恐龙等爬行动物为主的中生代群落的基础。同样，一些两栖动物分支在古生代经历了快速且持续的多样化，因为它们进化为完全陆地的生活方式。在此背景下，Dissorophoids 具有重要意义和研究价值，因为它们在产生两栖动物（现存的两栖动物 - 青蛙、蝾螈和足足动物）之前作为陆地捕食者与羊膜动物共存。 对古生代陆地四足动物的解剖学、多样性和进化关系的长期研究将继续成为该提案的一部分，因为新发现对我们对脊椎动物进化的理解具有重大影响。在这个建议中，我将采取两管齐下的方法。首先，我将扩展我最近在牙齿解剖学、发育和替代方面的工作，并建议评估重建的摄食行为所反映的系统发育框架内分类和生态多样性的变化。我将研究形态变异（差异），包括比较系统发育和时间背景下的牙齿和下颌多样性，以便追踪早期羊膜动物和同时代的陆地四足动物在进化过程中进入以前无人居住的生态空间和新的食物资源的生态多样性。对连续古生代群落中牙齿和颌形状和大小变化的形态测量分析将被组织成从石炭纪晚期（316Ma）到二叠纪早期（272Ma）末期的时间段。其次，这种新方法将与其他骨骼变量结合起来，特别是从多模态 CT 数据得出的新神经颅解剖结构，纳入综合时间校准的系统发育分析。在系统发育框架内对生态和分类多样性模式的新颖使用代表了我们探讨脊椎动物进化这一重要章节的变革性方式之一。这些分析将首次揭示陆生脊椎动物进化初始阶段四足动物的群落结构和进化。