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RE: Tyrannosaur analogs in the south?



Quoting "Richard W. Travsky" <rtravsky@uwyo.edu>:

On Fri, 30 Mar 2007, Thomas R. Holtz, Jr. wrote:
From: owner-DINOSAUR@usc.edu [mailto:owner-DINOSAUR@usc.edu]On Behalf Of
Richard W. Travsky

The Late Cretaceous top predators of Gondwana were the Abelisauridae.
Not as big as the tyrannosaurids, nor were they particularly cursorial,
but like their distant northern kin they had stumpy arms.

Would that be a result of common origins or "lifestyle"?

Lifestyle (aka "convergence"), as more primitive tyrannosauroids (_Guanlong_, for example) and other coelurosaurs and basal tetanurines have much longer arms than tyrannosaurids.

So does that imply common origins?

Only in that both groups are neotheropods, in the sense that Bakker used the term (but then, so are allosaurids, birds, spinosaurids, therizinosauroids, noasaurids, oviraptorosaurs, troodonts, etc., etc., etc.).


The answer to your question (I think) is no, tyrannosaurids and abelisaurids are not at all closely related as theropods go, and their common ancestor was probably not very much like either group in terms of size or ecological niche.

--
Nick Pharris
Department of Linguistics
University of Michigan

"Creativity is the sudden cessation of stupidity."
    --Edwin H. Land