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Re: Reptilia



On Sun, 6 Dec 1998 Philidor11@aol.com wrote:

> So, definitions of reptilia are based on:
> 1. 4 limbs/scales/not lactating
So snakes aren't reptiles? The other two characters do not fossilize
(well, scales do, but pretty rarely), so they don't make for a very good
diagnostic characters. Is _Cynognathus_ a reptile? Is _Seymouria_? Is
_Dimetrodon_?

> 2. the windows (fenestra) system I was quoting from Fastovsky & Weishampel
> 1996
> 
> I'd appreciate it if anyone with a different definition could add it.  The
> mutability in this field is very interesting to me.

The cladistic definition was mentioned before, but I'll mention it again:
the most recent common ancestor of chelonians (turtles), _Sphenodon_
(tuatara), squamates (lizards and snakes), and crocodylians, plus all of
its descendants.

See: http://umbc.edu/~tkeese1/dinosaur/taxa/sauropsi.htm

--T. Mike Keesey                                   <tkeese1@gl.umbc.edu>
THE DINOSAURICON                http://www.gl.umbc.edu/~tkeese1/dinosaur
(shameless plug) vote at http://www.coolsiteoftheday.com/csoty/98reference.html