Patterns and processes in the evolution of morphological novelty in the amphibian skull

两栖动物头骨形态新颖性进化的模式和过程

• 批准号: RGPIN-2020-06442
• 负责人: Maddin, Hillary
• 金额: $ 2.91万
• 依托单位: Carleton University
• 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=718329
• 关键词: Patterns; processes; evolution; morphological; novelty

Evolutionary transformations are responsible for the origin of the great diversity of animal form, past and present. Evolutionary transformations, such as the transformation from fins to limbs, have captured the attention of naturalists for centuries and have provided the observations needed to establish fundamental theories in evolutionary biology such as natural selection (i.e., decent with modification), the concept of homology, among others. One poorly understood transformation is that which characterizes the origin of the lissamphibian skull form. Lissamphibians (i.e., frogs, salamanders, and caecilians) comprise one half of the dichotomy of living, land-dwelling vertebrates (=tetrapods), the other half of the dichotomy being amniotes (mammals, reptiles and birds). The goal of the proposed research program is to identify and understand evolutionary events that took place in the origin of the distinct lissamphibian skull form. I HYPOTHESIZE that the distinct lissamphibian skull form is the result, at least in part, of shared evolutionary developmental events that took place during the common origin of frogs, salamanders and caecilians. I will address this hypothesis using complementary approaches, synthesizing paleontological data with that from lab-based experiments with living amphibians. I will also conduct fieldwork to retrieve new fossil material to help fill the gaps in the lissamphibian fossil record. The Carboniferous of Nova Scotia represents a critical time period in the evolution of amphibians and has already produced fossils of paramount significance, including the world's oldest amniote and reptile. My fieldwork in Nova Scotia has yielded a plethora of new important discoveries in the last five years, thereby highlighting Canada's natural heritage and adding a facet to Canada's paleontological significance. Study of this new, and currently known, material will reveal new aspects of the pattern of evolutionary events that gave rise to the lissamphibian skull form. Incorporation of data from developmental experiments will shed light on the mechanistic basis, or processes, underlying these evolutionary patterns. The results of this research will revise our understanding of this major tetrapod transformation. Traditionally, lissamphibians have been viewed as representatives of the primitive tetrapod condition, and, as such, are often used to understand the nature and direction of character transformations that seemingly define the well-studied amniote lineage. However, consideration of the fossil record reveals this is not the case, which has led to misinterpretations of evolutionary patterns involving them. Additionally, this research addresses fundamental questions concerning the tempo and mode of the evolution of animal diversity, on multiple hierarchical levels, through the completion of projects spanning Deep- to Real-time.

进化的转变是动物形态多样性的起源，无论是过去的还是现在的。进化转化，如从鳍到四肢的转变，几个世纪以来一直吸引着自然学家的注意，并提供了建立进化生物学基本理论所需的观察结果，如自然选择(即适当的修饰)、同源概念等。一种鲜为人知的转变是描述利桑菲斯头骨形式起源的特征。生活在陆地上的脊椎动物(=四足动物)中有一半是里萨姆菲比亚(即青蛙、火蜥蜴和盲肠动物)，另一半是羊膜动物(哺乳动物、爬行动物和鸟类)。拟议的研究计划的目标是识别和了解在独特的利桑菲斯头骨形式的起源中发生的进化事件。我推测，独特的蜥蜴头骨形状至少在一定程度上是在青蛙、火蜥蜴和蜥蜴的共同起源期间发生的共同进化发育事件的结果。我将使用互补的方法来解决这一假设，将古生物学数据与基于实验室的活体两栖动物实验数据进行合成。我还将进行田野工作，找回新的化石材料，以帮助填补利桑菲亚化石记录中的空白。新斯科舍省的石炭纪代表着两栖动物进化的关键时期，已经产生了具有极其重要意义的化石，包括世界上最古老的羊膜动物和爬行动物。在过去的五年里，我在新斯科舍省的田野工作产生了太多的新的重要发现，从而突出了加拿大的自然遗产，并增加了加拿大古生物学意义的一个方面。对这种新的、目前已知的材料的研究将揭示导致利桑菲斯头骨形态的进化事件模式的新方面。结合来自发育实验的数据，将揭示这些进化模式背后的机制基础或过程。这项研究的结果将修正我们对这一重大四足动物转变的理解。传统上，利桑菲亚人一直被视为原始四足动物状况的代表，因此，他们经常被用来理解角色转变的性质和方向，这些转变似乎定义了研究得很好的羊膜动物血统。然而，对化石记录的研究表明，情况并非如此，这导致了对涉及它们的进化模式的误解。此外，这项研究通过完成从深度到实时的项目，在多个层级上解决关于动物多样性进化的节奏和模式的基本问题。