title: Tyrannosaur paleobiology: new research on ancient exemplar organisms.
abstract: Tyrannosaurs, the group of dinosaurian carnivores that includes Tyrannosaurus rex and its closest relatives, are icons of prehistory. They are also the most intensively studied extinct dinosaurs, and thanks to large sample sizes and an influx of new discoveries, have become ancient exemplar organisms used to study many themes in vertebrate paleontology. A phylogeny that includes recently described species shows that tyrannosaurs originated by the Middle Jurassic but remained mostly small and ecologically marginal until the latest Cretaceous. Anatomical, biomechanical, and histological studies of T. rex and other derived tyrannosaurs show that large tyrannosaurs could not run rapidly, were capable of crushing bite forces, had accelerated growth rates and keen senses, and underwent pronounced changes during ontogeny. The biology and evolutionary history of tyrannosaurs provide a foundation for comparison with other dinosaurs and living organisms.
authors.affiliation: Division of Paleontology, American Museum of Natural History, Central Park West at 79th Street, New York, NY 10024, USA. sbrusatte@amnh.org
authors.forename: Stephen L
authors.initials: SL
authors.lastname: Brusatte
authors.forename: Mark A
authors.initials: MA
authors.lastname: Norell
authors.forename: Thomas D
authors.initials: TD
authors.lastname: Carr
authors.forename: Gregory M
authors.initials: GM
authors.lastname: Erickson
authors.forename: John R
authors.initials: JR
authors.lastname: Hutchinson
authors.forename: Amy M
authors.initials: AM
authors.lastname: Balanoff
authors.forename: Gabe S
authors.initials: GS
authors.lastname: Bever
authors.forename: Jonah N
authors.initials: JN
authors.lastname: Choiniere
authors.forename: Peter J
authors.initials: PJ
authors.lastname: Makovicky
authors.forename: Xing
authors.initials: X
authors.lastname: Xu
mesh_terms: D000818:Animals; D001522:Behavior, Animal; D005075:Biological Evolution; D025061:Dinosaurs / Q000033:anatomy & histology / Q000254:growth & development / Q000502:physiology; D017753:Ecosystem; D005580:Fossils; D010802:Phylogeny; D011157:Population Dynamics