Tyrant dinosaur evolution tracks the rise and fall of Late Cretaceous oceans.
The Late Cretaceous (∼95-66 million years ago) western North American landmass of Laramidia displayed heightened non-marine vertebrate diversity and intracontinental regionalism relative to other latest Cretaceous Laurasian ecosystems. Processes generating these patterns during this interval remain poorly understood despite their presumed role in the diversification of many clades. Tyrannosauridae, a clade of large-bodied theropod dinosaurs restricted to the Late Cretaceous of Laramidia and Asia, represents an ideal group for investigating Laramidian patterns of evolution. We use new tyrannosaurid discoveries from Utah--including a new taxon which represents the geologically oldest member of the clade--to investigate the evolution and biogeography of Tyrannosauridae. These data suggest a Laramidian origin for Tyrannosauridae, and implicate sea-level related controls in the isolation, diversification, and dispersal of this and many other Late Cretaceous vertebrate clades.
Natural History Museum of Utah and Department of Geology & Geophysics, University of Utah, Salt Lake City, Utah, United States of America.
Mark A
MA
Loewen
Randall B
RB
Irmis
Joseph J W
JJ
Sertich
Philip J
PJ
Currie
Scott D
SD
Sampson
D000818:Animals; D005075:Biological Evolution; D025061:Dinosaurs / Q000033:anatomy & histology; D055669:Ecological and Environmental Phenomena; D009792:Oceans and Seas; D010163:Paleontology; D012886:Skull / Q000033:anatomy & histology