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Re: Bird Question

On Fri, 2 Feb 1996 Dinogeorge@aol.com wrote:

> >> Naturally, there must also have been a Jurassic bird radiation, of which
> >> _Archaeopteryx_ was a part. 
> >
> >Agreed.  IMHO, the Arctometatarsalia are also a part of this radiation, 
> >but you are free to disagree, as many do.
> Ah--but I don't disagree here. I have this idea that some of the more
> birdlike theropods were not just giant, cursorial dino-birds but giant,
> cursorial enantiornithans. These might include avimimids, oviraptorids, and
> elmisaurids. But there's not much information published on enantiornithans to
> hang your hat on yet.

Ah--but if you insist that tyrannosaurs are descended from compsognaths, 
then you do disagree!  I think oviraptorosaurs are too primitive to be 
true birds (more on the level of dromaeosaurs), and that avimimids, 
ornithomimosaurs, troodonts, and tyrannosaurs are descended from a single 
early bird (maybe a relative of _Compsognathus_) that re-evolved a 
propubic pelvis.

Or, possibly, dromaeosaurs evolved their opisthopubic pelvis 
independently from birds, and arctomets actually did branch off before 
_Archaeopteryx_.  More study on Archie is called for.

Nick Pharris
Pacific Lutheran University
Tacoma, WA 98447

"If you can't convince them, confuse them." -- Harry S. Truman