Radiation and diversification patterns in early jawed vertebrates

有颌脊椎动物，或称颚口类，占现存脊椎动物物种的99.8%。现存的有颚鱼类包括约1 270种软骨鱼类（鲨鱼、鳐、鳐和银鲛）、29 000种鳍鱼（辐鳍鱼）和33 880种四足动物（包括我们自己的物种）。这种特殊的多样性是4.4亿年历史的结果，伴随着进化辐射事件。早期有颚类的主要创新包括颚和牙齿的出现，成对的嗅觉器官，腹鳍和腹带以及内生殖器官。这些解剖学上的新颖性提供了生态、行为和生殖优势，这可能与它们早期的适应性辐射有关。泥盆纪（419-359 Ma）的有颚类动物分布广泛，几乎只生活在水生环境中，占据了整个食物网，大小从2 cm到4 m不等。在过去的十年中，新的有颌脊椎动物化石的发现，新的尖端技术（微米和纳米CT扫描，同步加速器X射线显微断层扫描）和新的分析方法的使用，揭示了颚口动物的发育。有颌类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，这些设想都没有被纳入大规模的生物发生学框架，以检验关于可能引发辐射的生物和非生物因素的假设。尽管辐射在生命进化过程中至关重要，但仍然缺乏一个进化辐射假说的综合框架。 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学的快速分化方面的快速时间变化来记录有颌脊椎动物的进化辐射。所有这些组成部分将被整合到一个新的系统发育框架，以确定作为辐射驱动因素的因素。这种对有颚类起源的“时间、地点和方式”的探索将导致一种综合和创新的方法来研究分类群的起源和早期辐射。我希望利用有颌脊椎动物的辐射，为进化辐射的一般理论以及培养高素质的进化生物学人才做出贡献。越来越多的解释过去-最近的过去和深时间-有助于理解产生和维持时间和空间多样性的过程。更好地理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。

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 33 880 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- and nano-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 into a novel phylogenetic framework in order to identify factors acting as drivers of radiations. This quest for the "when, where and how" gnathostomes originated will led to an integrative and innovative approach to studying the origin and early radiation of taxonomic groups. Using the jawed vertebrate radiation, I wish to contribute to the general theory of evolutionary radiations as well as training highly qualified personnel in evolutionary biology. Increasingly interpretation of the past-both recent past and deep time-helps to understand the processes that generate and maintain diversity in time and space. A better understanding of evolutionary radiations and triggering factors is essential to comprehend not only past evolution but also the ongoing effects of global changes on biodiversity.