YOUNG SCIENTIST AWARD (DONATH MEDAL): RETHINKING THE RISE OF DINOSAURS AND THEIR KIN: NEW FOSSILS HAVE RESHAPED HOW WE CHARACTERIZE THE ORIGIN OF DINOSAURS

Dinosaurs, the dominant terrestrial vertebrates of the Mesozoic Era, were unmistakably successful. They were abundant, distributed across the globe, had many different sizes and shapes, and had high diversity throughout much of their history. For years, paleontologists focused on determining which characteristics made the early dinosaurs successful and unique. However, new fossils of dinosaurs and especially their closest relatives (dinosaur precursors) have signaled that dinosaurs had a humble beginning in the Triassic Period. Nearly complete skeletons of a variety of dinosaur precursors demonstrate that those relatives possessed almost all of the characteristics once thought to be unique to dinosaurs (e.g., morphological, growth) and that there is as much disparity in dinosaur precursors as in early dinosaurs. Temporal and geographic overlap between dinosaurs and dinosaur precursors demonstrates that the early dinosaurs lacked a ‘competitive edge’ inherent to the traditional dinosaur success narrative. This and other new data indicate that dinosaurs were merely part of a larger radiation of reptiles (the archosaurs) more closely related to birds than to crocodylians and this diversification was likely triggered by recovery after the end-Permian Mass Extinction. Dinosaurs, in turn, only began to rule the terrestrial realm after the end-Triassic Mass Extinction some 30 million years after their origin.