Tuesdays: 12:15 p.m. - 1:00 p.m.
417 Schermerhorn

Bring your lunch if you like.
All are welcome!

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Tuesday, September 21

Steve Brusatte - Tyrannosaur phylogeny and biology: new research on ancient model organisms

Summary: Tyrannosaurus is the most feared and familiar of all of the dinosaurs, but recent fossil discoveries give a startling new picture of tyrannosaur evolution. Five important new species have been revealed over the past year, running the gamut from some of the most primitive and smallest members of the group to completely bizarre forms. Raptorex is barely larger than a man but has all of the classic tyrannosaur features, such as the large skull and puny arms, indicating that the tyrannosaur body plan first evolved at small size and not in giant bone-crunchers. Alioramus, from the Late Cretaceous of Mongolia, is one of the closest cousins of Tyrannosaurus but is only half its size and has a bizarre long snout and eight horns on its skull. Sinotyrannus is one of the oldest tyrannosaurs, but was nearly the size of T. rex itself! These, and other discoveries, are overturning previous theories about tyrannosaur evolution. The tyrannosaur group was a long-lived lineage that began with small species in the Middle Jurassic. For the first 80 million years of their history tyrannosaurs remained small animals, until rapidly developing colossal size at the end of the Cretaceous. I have studied many of these specimens and will discuss the latest views on tyrannosaur evolution and biology, using as a guide a newly-published phylogenetic analysis (family tree) that is a major part of my dissertation research.