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Re: Caudipteryx not a bird and more from APP



On Fri, 04 Feb 2005 22:22:17 -0600, Dora Smith <villandra@austin.rr.com> wrote:
> 
> It isn't proven birds are more closely related to each other than to other
> dinosaurs until their DNA has been compared to that of other dinosaurs.
> 
> So far it's only been compared to crocodiles.   Now all dinosaurs are more
> closely related to each otehr than to crocodiles.

That would be true if DNA were the only form of evidence we had. By
your reasoning, it would be possible, e.g., for dicynodonts to be
closer to marsupials than placentals or monotromes are. We can't
disprove it genetically, after all! But we can discard the hypothesis
based on morphological grounds, just as we can discard the idea that
the closest common ancestor of modern birds lacked neornithean traits.
The amount of convergence that hypothesis would require is *extremely*
unparsimonious.
 
And besides, there is genetic evidence (molecular clock) that the
clade of modern birds arose after the appearance of those birdlike
clades (deinonychosaurs, oviraptorosaurs, etc.)

-- Mike Keesey