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.
