Re: Trike fights

[Robert.J.Meyerson@uwrf.edu (Rob Meyerson)]

>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.

O.K, But how can that work for animals like T-tops, that don't have any holes in
that area.  The only way for the muscle to get to the upper frill is to go
outside the head (as an aside, the noch between the jugal and the frill could be
where the jaw muscle went).

Is it possible that _Psittacosaurus_ had a series of jaw muscles; one set that
went through the head, and up to the frill; and a set that went outside the jaw?
In the case of T-tops, it would only mean that the outer muscle took control of
chewing.  OTOH, since T-tops evolved from short frilled ceratopians, it could be
that this is a characteristic of the group.

Rob

***
"Don't panic!"