Re: Trike fights

["Nicholas J. Pharris" <pharrinj@PLU.edu>]

On Thu, 25 Jan 1996, Rob Meyerson wrote:

> >In a message dated 96-01-25 11:21:20 EST, Robert.J.Meyerson@uwrf.edu (Rob
> >Meyerson) writes:
> >
> >>Being somewhat analogous=
> >> to a block-and-tackle we use for lifting heavy objects, the jaw muscle=
> >> appears to originate at the middle of the jaw, slide along the jugal, then=
> >> up to the frill for it's insertion. 
> >
> >What, the _outside_ of the jugal??
> 
> I think so.  The only opening in the skull, at that region, is the ear.  There
> doesn't appear to be any way that the jaw muscle could attach to the underside
> of the frill, so it had, IMHO, to attach to the upper frill (which is fairly
> well supported by other sources).  

Yes, the jaw muscles did attach to the top of the frill, but they got 
there via spaces *inside* the skull.  Check out a _Psittacosaurus_ 
skull.  The jaw musculature runs from the coronoid eminence straight up 
through the inside of the skull.  The jaw muscles of neoceratopians 
worked the same way, running up through holes in the top of the skull 
(the supratemporal fenestrae, present in all diapsids) and out over the 
frill.

> 
> Rob
> 

Nick Pharris
Pacific Lutheran University
Tacoma, WA 98447
(206)535-8204
PharriNJ@PLU.edu

"If you can't convince them, confuse them." -- Harry S. Truman