Tyrannosaurus rex (image) American Museum of Natural History Caption Tyrannosaurus rex, shown in this artistic illustration, is part of the carnivorous groups of dinosaurs that, according to new research, maintained a stable level of biodiversity leading up to the mass extinction at the end of the Cretaceous. Credit AMNH/J. Brougham Usage Restrictions Can be used as long as appropriate credit is given. Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.