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Re: Quo vadis, T. rex?



On Thu, 1 Feb 1996 Dinogeorge@aol.com wrote:

> In a message dated 96-02-01 20:37:01 EST, pharrinj@PLU.edu (Nicholas J.
> Pharris) writes:
> 
> >What I do not agree with is the linking of tyrannosaurs with the much 
> >more primitive (ornitholestid-grade) _Compsognathus_ purely on the 
> >occurrence of the didactyl condition in these two taxa (or that the 
> >arctomet foot evolved in tyrannosaurs from scratch, i.e. from a 
> >completely uncompressed foot like that of _Compsognathus_).
> 
> Actually, take a look at the pelvic bones of _Compsognathus_ and see how
> closely they resemble miniature versions of tyrannosaurid pelvic bones. Grow
> a bit of pubic boot, lose a bit of distal ischial enlargement, and "Voila," a
> tyrannosaurid pelvis.

Or take an ornithomimid pelvis, scale it up, and "Voila`," a 
tyrannosaurid pelvis in one easy step.

 
> It really begins to look as if tyrannosaurians grew into ferocious monsters
> quite on their own, as a separate theropod lineage with no particularly close
> sister groups among the other Cretaceous dinosaurs. 

Possibly, but IMHO, they are still post-archaeopterygian birds (the two 
are by no means mutually incompatible).


> Compy's not their
> _direct_ ancestor, but it could well be close.
 
Again I say, if Compy proves to have a cryptometatarsalian foot, with 
metatarsal III shrouded at the ankle joint, and an avian V1 
configuration, then we'll talk.

Later!

Nick Pharris
Pacific Lutheran University
Tacoma, WA 98447
(206)535-8204
PharriNJ@PLU.edu

"The gene pool needs a little chlorine."