Assessment of Dinosaur Diversity and Sediment Coverage in Cretaceous North America

Shan Ye

Abstract: Whether the diversity of North American dinosaurs was decreasing prior to the K/Pg extinction has long been debated. Some hypothesize the diversity of North American non-avian dinosaurs declined gradually in the latest Cretaceous since Campanian, making them susceptible to extinction. Alternatively, others propose dinosaurs show no obvious decline in diversity and suffered an abrupt extinction during the catastrophic vents of the K/Pg boundary. Time series of dinosaur diversity has been constructed to analyze the extinction process of dinosaurs, but it has been proposed that the diversity record of North American dinosaurs is likely biased by the fossil sampling and the availability of sediments. To better understand the pattern of dinosaur extinction in North America, here we use Macrostrat and Paleobiology Database to reconstruct the dinosaur diversity, geological map areas of sediments, and sub-surface sedimentary rock distributions in Cretaceous North America from a spatiotemporal perspective. Our reconstructions show significant positive correlations between fossil preservation and map areas. These results illustrate that the availability of sedimentary rocks could influence the abundance of dinosaur fossils over time, and thus it might have influenced the spatiotemporal reconstruction of the dinosaur diversity and our perception of diversity and the macroevolutionary process leading into the K/Pg extinction. Our time series analysis indicates that dinosaur diversity reached a high level in Campanian and Maastrichtian and then had an abrupt decrease approaching the end of the Maastrichtian. Our results show that there is no evidence for a long-term decline of dinosaur diversity in North America before the abrupt decline at the K/Pg mass extinction.

Time: April 21st (14:30)

Advisor: Shanan Peters

Co-Authors: Scott Hartman, Shanan Peters

Stream: Zoom

Email: shan.ye@wisc.edu