Multifaceted disparity approach reveals dinosaur herbivory flourished before the end-Cretaceous mass extinction

Understanding temporal patterns in biodiversity is an enduring question in paleontology. Compared to studies of taxonomic diversity, long-term perspectives on ecological diversity are rare, particularly in terrestrial systems. Yet ecological diversity is critical for the maintenance of biodiversity, particularly during times of major perturbations. Here, we explore the ecological diversity of Cretaceous herbivorous dinosaurs leading up to the K-Pg extinction, using dental and jaw morphological disparity as a proxy. We test the hypothesis that a decline in ecological diversity could have facilitated their rapid extinction 66 mya. We apply three disparity metrics that together capture different aspects of morphospace occupation, and show how this approach is key to understanding patterns of morphological evolution. We find no evidence of declining disparity in herbivorous dinosaurs as a whole – suggesting that dinosaur ecological diversity remained high during the last 10 million years of...