Ecology and Diversity Dynamics of Late Cretaceous Dinosaurs

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The pattern of terrestrial vertebrate diversity leading to the mass extinction event that marks the end of the Age of Dinosaurs continues to be hotly debated, with the well-sampled fossil record of North America forming the basis for differing hypotheses on the ultimate causes of this major biodiversity crisis in Earth History. How biotic and abiotic factors interacted during this biotic crisis shaped patterns of extinction selectivity, with survivors radiating as ecosystems restructured to shape the modern world. The goal of this program is to resolve palaeobiodiversity and palaeoecological patterns in latest Cretaceous (84-66 million years ago) dinosaurs (including birds), and evaluate their relationship to climatic and environmental changes in North America. Over the next five years, this program aims to: 1) resolve the species richness and diversity dynamics of dinosaurs from western North America in the last 20 million years of the Mesozoic, 2) quantify morphological disparity and functional diversity of key dinosaur assemblages to reconstruct Late Cretaceous palaeoecological dynamics and inform food web models, 3) reconstruct large-scale historical biogeographic patterns to test hypotheses of dinosaur provinciality and climatic and sea-level controls on their biogeography, and 4) integrate new dinosaur diversity and ecology data with that of other terrestrial organisms and employ ecological modelling approaches to understand palaeoecological dynamics and extinction. Although dinosaurs are often portrayed as iconic victims of this mass extinction, understanding extinction selectivity and the survival of birds makes them an important model clade for studies of macroevolutionary and ecological dynamics in terrestrial vertebrates. Research in this proposal will provide fundamental new data and the requisite frameworks for understanding the role of large-scale climatic and environmental changes on patterns of dinosaur evolution, biogeography, and diversity leading up to the end-Cretaceous extinction event. New results on dinosaur diversity, community structure and ecology will inform novel models of food web interactions (e.g., CEG modelling) that will be used to evaluate patterns of ecological stability and resilience leading up to the major perturbations (e.g., bolide impact, volcanism) at the end of the Cretaceous, and lead to a better understanding of dinosaur extinction patterns. A clearer understanding of the evolutionary and ecological dynamics of dinosaurs as they relate to climate change preceding and through this extinction event will shed new light on the causes and consequences of mass extinctions in general, which is timely and relevant to the biodiversity crisis we are facing today.