The dinosaur boom in the Cretaceous

Abstract

Abstract Dinosaurs were thriving at the beginning of the Cretaceous, and yet major changes had occurred across the Jurassic–Cretaceous boundary. The sauropods were replaced by ornithopods as dominant herbivores, which has been explained by many ecological scenarios, including the replacement of gymnosperms by angiosperms as dominant land plants. The ornithischians went on to radiate substantially in the mid and Late Cretaceous, with the key clades (hadrosaurs, ceratopsians, ankylosaurs) specializing in different feeding modes and diets, and reaching huge abundance in many faunas. New computational methods allow palaeobiologists to assess aspects of the palaeobiology, macroecology and macroevolution of dinosaurs through the Cretaceous in testable and repeatable ways. These new approaches have shed light on many mysteries, such as whether dinosaurs ate flowers, why the hadrosaurs were so successful and why some theropods became larger or smaller, or switched from carnivory to herbivory. There are further debates around the final demise of dinosaurs, where regional and global data suggest the group was in decline through the latter part of the Late Cretaceous before they were finished by the asteroid impact.