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RE: Sneak Peak at Yale Torosaurus Sculpture



> -----Original Message-----
> From: owner-dinosaur@usc.edu [mailto:owner-dinosaur@usc.edu] On Behalf Of
> David Marjanovic
> Sent: Tuesday, September 27, 2005 11:17 AM
> To: DML
> Subject: Re: Sneak Peak at Yale Torosaurus Sculpture
> 
> > Well. . .maybe ceratopsids didn't have cheeks? I was initially resistant
> > to
> > this when Witmer first presented the idea, but then I started looking a
> > little more closely on some real specimens. In most ceratopsid skulls,
> the
> > anastomosing neurovascular impressions lead right up to the tooth row.
> 
> Those could indicate a beak, lips or cheeks, couldn't they? What about
> gums
> that were thick enough to protect the sides of the tooth batteries?

These are the same style of neurovascular impressions that are found across
the surface of the skull. If muscular cheeks were attaching in this area, I
would expect a much smoother bone surface. Likewise, gums (at least the ones
I've seen and dissected) are typically associated with smooth bone. Anyone
know any exceptions to this? It's always been my impression that the
anastomosing neurovascular impressions are associated with a tight-fitting
covering of skin, keratin, or meninges.

> 
> > Of course, I totally think Toro (and most other ceratopsids) would look
> > better with some nice cheeks, but the evidence just doesn't support it
> in
> > this group. Maybe a flap of skin at best? Who knows. . .
> 
> Of course I have no idea whether a mammal-style muscular cheek was
> present.
> But nothing at all, as in the sculpture, would mean that a lot of food
> routinely fell out of the mouth.

But. . .turtles, tortoises, iguanas, and herbivorous birds get along just
fine without cheeks. So did herbivorous crocs.

Does anyone know of any non-mammals that get cheek-like structures?

Andy

________________________________
Andrew A. Farke, Graduate Student
Department of Anatomical Sciences
Stony Brook University
T8 040 Health Sciences Center
Stony Brook, NY  11794-8081