Re: Birds?Dinos?

["T. Mike Keesey" <tkeese1@gl.umbc.edu>]

On Sun, 4 Oct 1998, GOBI 2010 wrote:

> Okie,
> I've been wondering about this question for a while...
> Because of the new feathered dinosaurs, and other discoveries, what is a 
> bird and what is a dinosaur? Or are they the same thing, or is a bird a 
> dinosaur that flies/glides and a dinosaur a bird that's grounded? (Would 
> that make 'flightless birds' dinosaurs???).....
> The more I puzzle about this, the more I get confused, and the more 
> crazy it seems to me.

They are all dinosaurs, flightless or not. Any creature descended from the
most recent common ancestor of _Triceratops_ and modern birds is, by the
cladistic definition of Dinosauria, a dinosaur.

"Bird" is a vernacular term, so it is subject to some variation. I use it
for members of the clade Aves (the most recent common ancestor of
_Archaeopteryx_ and modern birds, plus all of its descendants). People
also use it for Avialae (all animals sharing more recent ancestry with
modern birds than with _Deinonychus_). 

By my criterion, _Caudipteryx_ and _Protarchaeopteryx_, at least according
to the phylogeny published by the authors, are not birds (but pretty
close).

--T. Mike Keesey                                   <tkeese1@gl.umbc.edu>
DINOSAUR WEB PAGES -- http://www.gl.umbc.edu/~tkeese1/dinosaur/index.htm