Evolutionary radiations of early jawed vertebrates: a multifactorial (phylogenetic, morphological, developmental and ecological) perspective

早期有颌脊椎动物的进化辐射：多因素（系统发育、形态学、发育和生态）视角

• 批准号: RGPIN-2017-06200
• 负责人: Cloutier, Richard
• 金额: $ 1.53万
• 依托单位: Université du Québec à Rimouski
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2017
• 资助国家: 加拿大
• 起止时间: 2017-01-01 至 2018-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=631631
• 关键词: Evolutionary; radiations; early; jawed; vertebrates

Jawed vertebrates, or gnathostomes, account for 99.8% of living vertebrate species. Living gnathostomes include some 1 270 species of cartilaginous fishes (sharks, skates, rays and chimaeras), 29 000 species of ray-finned fishes (actinopterygians) and 31 800 species of tetrapods including our own species. This exceptional diversity is the result of a 440-million-year-long history that has been accompanied by events of evolutionary radiations. Early gnathostome key innovations include the presence of jaws and teeth, paired olfactory organs, pelvic fins and girdles and intromittent reproductive organs. These anatomical novelties have provided ecological, behavioral and reproductive advantages that were presumably associated with their early adaptive radiation. Because of these novelties, Devonian (419-359 Ma) gnathostomes were cosmopolitan in distribution, lived almost exclusively in aquatic habitats, occupied the whole food web and ranged in size from 2 cm to 4 m. Over the past decade, the discovery of new fossils of jawed vertebrates, the use of new cutting-edge technologies (micro-CT scan, synchrotron X-ray microtomography) and new analytical methods have shed light on gnathostome phylogeny. The evolutionary success of gnathostomes has been attributed alternately to the origin of the key innovations, ecological or environmental shifts, or their paleogeographic distribution. However, none of these scenarios have been framed in a broad-scale phylogeny in order to test hypotheses about biotic and abiotic factors which might have triggered the radiation. Notwithstanding the paramount importance of radiations during the evolution of life, an integrative framework for evolutionary radiation hypotheses is still lacking. For the next 5 years, the main goal of my research program will be to document the evolutionary radiation of jawed vertebrates by identifying rapid temporal changes in terms of the number of species, rates of evolution as well as rapid divergences in morphology and ecology. All these components will be integrated in a novel phylogenetic framework in order to identify factors acting as drivers of radiations. This quest for the “when, where and how” gnathostomes originated should led to an integrative and innovative approach to study the origin and early radiation of taxonomic groups. Using the jawed vertebrate radiation, I wish to contribute to the general theory of evolutionary radiations. Increasingly interpretation of the past—both recent past and deep time—helps understanding of the processes that generate and maintain diversity in time and space. A better understanding of evolutionary radiations and triggering factors is essential to comprehending not only past evolution but also the ongoing effects of global changes on biodiversity.

有颌脊椎动物，或称颌口动物，占现存脊椎动物物种的99.8%。现存的颌口动物包括约1270种软骨鱼（鲨鱼、鳐鱼、鳐鱼和银鱼）、29000种鳍状鱼类（放光鳍类）和3800种四足动物（包括我们人类）。这种特殊的多样性是4.4亿年历史的结果，伴随着进化辐射的事件。早期啮齿动物的关键创新包括颌骨和牙齿的出现，成对的嗅觉器官，腹鳍和腹带以及隐蔽性生殖器官。这些解剖学上的新奇提供了生态、行为和生殖方面的优势，这可能与它们早期的适应性辐射有关。由于这些新特征，泥盆纪（419-359 Ma）的颌口动物分布广泛，几乎完全生活在水生栖息地，占据了整个食物网，大小从2厘米到4米不等。在过去的十年里，新颌骨脊椎动物化石的发现，新尖端技术（微ct扫描，同步加速器x射线微断层扫描）和新分析方法的使用，使人们对颌口动物的系统发育有了新的认识。颌口动物的进化成功被交替地归因于关键创新的起源、生态或环境的变化或它们的古地理分布。然而，为了检验可能引发辐射的生物和非生物因素的假设，这些情景都没有在大范围的系统发育中建立起来。尽管辐射在生命进化过程中具有至高无上的重要性，但目前仍缺乏一个完整的辐射进化假说框架。在接下来的5年里，我的研究计划的主要目标将是通过识别物种数量，进化速度以及形态和生态的快速分化方面的快速时间变化来记录颌骨脊椎动物的进化辐射。所有这些组成部分将被整合在一个新的系统发育框架中，以确定作为辐射驱动因素的因素。这种对“何时、何地、如何”颌口起源的探索，应该导致一种综合和创新的方法来研究分类类群的起源和早期辐射。我希望利用有颌脊椎动物的辐射，对进化辐射的一般理论作出贡献。越来越多的对过去的解释——包括最近的过去和久远的过去——有助于理解产生和维持时间和空间多样性的过程。更好地了解进化辐射和触发因素不仅对理解过去的进化，而且对理解全球变化对生物多样性的持续影响至关重要。