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: 2022
• 资助国家: 加拿大
• 起止时间: 2022-01-01 至 2023-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=751155
• 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.

进化转变是过去和现在动物形态多样性起源的原因。进化转变，例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础理论所需的观察结果，例如自然选择（即，体面与修改），同源性的概念，等等。一个鲜为人知的转变是利桑菲比亚头骨形态起源的特征。Lissampibians（即，青蛙、蝾螈和螈）构成了现存的陆栖脊椎动物（=四足动物）的二分体的一半，二分体的另一半是脊椎动物（哺乳动物、爬行动物和鸟类）。拟议的研究计划的目标是确定和理解在独特的利桑菲比亚头骨形式的起源中发生的进化事件。我假设，不同的利桑菲比亚头骨形状是在青蛙、蝾螈和螈共同起源期间发生的共同进化发育事件的结果，至少部分是这样。我将使用互补的方法来解决这个假设，综合古生物学数据和基于实验室的两栖动物实验。我还将进行实地考察，以获取新的化石材料，以帮助填补利桑菲比亚化石记录的空白。新斯科舍省的石炭纪是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两栖动物和爬行动物。在过去的五年里，我在新斯科舍省的实地考察取得了大量新的重要发现，从而突出了加拿大的自然遗产，并为加拿大的古生物学意义增加了一个方面。对这种新的、目前已知的材料的研究将揭示导致利桑菲比亚头骨形态的进化事件模式的新方面。从发育实验中获得的数据将有助于阐明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订我们对这一主要四足动物转变的理解。传统上，利桑菲比亚人被视为原始四足动物的代表，因此，经常被用来理解性格转变的性质和方向，这些变化似乎定义了研究得很好的利桑菲比亚人谱系。然而，对化石记录的考虑表明情况并非如此，这导致了对涉及它们的进化模式的误解。此外，这项研究解决了有关动物多样性进化的克里思和模式的基本问题，在多个层次上，通过完成从深度到实时的项目。