[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index][Subject Index][Author Index]

RE:Ceratopian jaws



On Wed, 11 Dec 1996, Robert J Meyerson wrote:

> >Muscles need area's to attach to, right? IF the jaw muscles attached to 
> >the frill like you say, on the frill, around the fenestra, there is a 
> >BIG problem. The middle of the muscle has to attach to something but 
> >there is a hole, there is NOTHING there to attach to. It wouldn't work.
> 
> I don't see the problem in this.  I envision the jaw muscle being similar
> to the strap on my backpack: Long but thin, with the long muscle fibers
> oriented with the long axis of the muscle.  In this senario, the muscle
> bulges through the fenestra as the animal chews.  This is not an outlandish
> assertian

  It probably is. Longer muscles can contract over greater distances, but 
the strength of a muscle is directly related to it's cross sectional 
area. This is why modern herbivores tend o have short, broad sheets of 
muscle to pull om the jaw; because it develops much more force. 

>, the earliest mammals had a single, small fenestra located at the
> temples.  In modern mammals, this fenestra has opened considerably,
> allowing the muscle to bulge unhindered by the bone as the animal chews.

        The earliest mammals, it was my impression, were really tiny 
and probably ate bugs, small animals, or seeds. Making arguments about 
the functional anatomy  of a 5 tonne grazer from the anatomy of a tiny 
insectivore not even related to  doesn't make a lot of sense.