Re: Dinosaurian Class

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

On Sun, 21 Jun 1998, William Hinchman wrote:

> T. Mike Keesey wrote:
> 
> > I'm not sure what the exact cladistic definition of Diapsida is, but it
> > falls somewhere between Sauria (+Lepidosauria, +Archosauria) and the more
> > inclusive Romeriida (+Sauria, -Chelonia). Romeriida is the sister group to
> > Anapsida (+Chelonia, -Sauria).
> 
> Isn't Diapsida's primary defining feature "Two Holes", which include the
> Infra Temporal openings, and also the openings on top of the skull
> bordering the pineal opening? 

That's how the group is diagnosed, not defined.

> Diapsids fall (cladistically) between Sauropsids (Reptilia)
(Sauropsida is not the same as Reptilia -- it is slightly more inclusive)
> and the Archosauria. 
Yes. I was being more specific -- Romeriida is between Reptilia and
Diapsida, and Sauria is between Diapsida and Archosauria.

> I tried to look at the URL provided in your posting, but I get a not
> found message.

Whoops! I meant http://umbc.edu/~tkeese1/dinosaur/taxa/animalia.htm

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