title: Dinosaur morphological diversity and the end-Cretaceous extinction.
abstract: The extinction of non-avian dinosaurs 65 million years ago is a perpetual topic of fascination, and lasting debate has focused on whether dinosaur biodiversity was in decline before end-Cretaceous volcanism and bolide impact. Here we calculate the morphological disparity (anatomical variability) exhibited by seven major dinosaur subgroups during the latest Cretaceous, at both global and regional scales. Our results demonstrate both geographic and clade-specific heterogeneity. Large-bodied bulk-feeding herbivores (ceratopsids and hadrosauroids) and some North American taxa declined in disparity during the final two stages of the Cretaceous, whereas carnivorous dinosaurs, mid-sized herbivores, and some Asian taxa did not. Late Cretaceous dinosaur evolution, therefore, was complex: there was no universal biodiversity trend and the intensively studied North American record may reveal primarily local patterns. At least some dinosaur groups, however, did endure long-term declines in morphological variability before their extinction.
authors.affiliation: Division of Paleontology, American Museum of Natural History, Central Park West at 79th Street, New York, New York 10024, USA. sbrusatte@amnh.org
authors.forename: Stephen L
authors.initials: SL
authors.lastname: Brusatte
authors.forename: Richard J
authors.initials: RJ
authors.lastname: Butler
authors.forename: Albert
authors.initials: A
authors.lastname: Prieto-Márquez
authors.forename: Mark A
authors.initials: MA
authors.lastname: Norell
mesh_terms: D000569:Americas; D000818:Animals; D044822:Biodiversity; D005075:Biological Evolution; D025061:Dinosaurs / Q000033:anatomy & histology* / Q000145:classification / Q000235:genetics*; D053476:Extinction, Biological; D005580:Fossils; D060434:Herbivory / Q000145:classification / Q000235:genetics*; D010163:Paleontology