Collaborative Research: Neosuchian Evolution and Crocodylian Origins - 190 Million Years of Biodiversity and Biogeographic Response to Climate and Tectonics

这项研究的重点是新鳄类的进化史--现存的短吻鳄、鳄鱼和gharials --以及它们最近的灭绝亲属。新鳄类在每个大陆上都有丰富的化石记录，跨越近2亿年。它们惊人地多样化，包括有鳍状肢和鲨鱼般尾巴的海洋动物，有铁砧般牙齿的小型粉碎形式，以及30英尺以上的巨人。新鳄类进化和多样性的许多方面尚不清楚。这包括灭绝物种的确切数量，几个谱系的相互关系，现代鳄鱼的地理起源，以及大规模地球变化的作用，包括气候和海平面的变化，在塑造新鳄类生物多样性中发挥作用。 研究人员将检查世界各地博物馆收藏的标本，包括化石和现代物种的骨骼，以收集新鳄类从起源到现在的全面、精确的历史。新鳄类是少数几个我们可以同时收集每一个现存物种的数据和大量灭绝物种化石样本的动物类群之一。该项目将进一步开发新鳄类作为研究探索和调和现存和灭绝物种数据之间冲突的模型组的用途。反过来，这将改善用于从分子数据估计发散时间的技术-这是现代生命科学的核心。由于它们的全球分布，新鳄类也将使我们能够在很长一段时间内探索多样性和气候的相互关系。反过来，这将改善保护现代鳄鱼物种的策略，其中一些物种严重濒危。

This research focuses on the evolutionary history of neosuchians -- living alligators, crocodiles, and gharials -- and their closest extinct relatives. Neosuchians have a rich fossil record on every continent spanning almost 200 million years. They were surprisingly diverse, including seagoing animals with flippers and sharklike tails, small crushing forms with anvil-like teeth, and 30+ foot giants. Many aspects of neosuchian evolution and diversity are unclear. This includes the exact number of extinct species, the interrelationships of the several lineages, the geographic origins of modern crocodylians, and the role large-scale earth changes, including changes in climate and sea level, played in shaping neosuchian biodiversity. The investigators will examine specimens in museum collections around the world, including fossils and the skeletons of modern species, to assemble a comprehensive, precise history of neosuchians from their origins to the present.Neosuchians are one of the few groups of animals for which we can simultaneously collect data from every living species and sample a substantial amount of extinct diversity with fossils. This project will further develop the use of neosuchians as a model group for studies exploring and reconciling conflicts between data from living and extinct species. This, in turn, will improve techniques used to estimate divergence time from molecular data - something central to the modern life sciences. Because of their global distribution, neosuchians will also allow us to explore the interrelationships of diversity and climate over very long time periods. This, in turn, will improve strategies to conserve modern crocodylian species, some of which are gravely endangered.