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Re: Blood flow in Sauropods



>From: pwillis@ozemail.com.au (Paul Willis)
 > Could you elusidate why a sauropod mouth is more cow-like than
 > elephant-like (any resemblance seems pretty rough to me).

I was speaking loosely.  The key factor is *breadth*.  An elephant's
mouth is (relatively) narrow. In faxt it is about as narrow as a mouth
of that size *can* be.  A sauropod mouth is relatively *very* broad.
In fact sauropod mouths may actually be relatively *broader* than
a cow's.
 > 
 > I would be a lot more comfortable with these arguements if you phrased them
 > with "appears to have been" rather than the absolute terms you present them
 > in.

Given the structure of the feeding apparatus, and known constraints
on feeding ecology, the conclusion that they were bulk feeders is
about as certain as it can get short of actually watching them.

 >  Even if sauropods fed by gulping down great quantities of green stuff
 > without much selection seems the most likely interpretation we can make of
 > the data, this is only a supposition and should be expressed as such.

It is stronger than "supposition".  It is more like: if they did
anything else they are unique amoung all tetrapods in feeding
ecology.

 > Probably the most fool-hardy assumption made here (what was not fossilised
 > from the Morrison world?).

We have a pretty could idea of the range of plant types then alive,
even if we do not know all the specific groups.  We also know that
the Morrison area was an arid landscape, probably with predominately
herbaceous vegetation.  Since grasses didn't evolve until the Eocene,
and at most only the most primitive, shrubby, angiosperms existed then,
this leaves only non-flowering plants as candidates for the herbaceous
cover. We also know that even today ferns sometimes form meadows
in a manner similar to grasses. This means that of the possible
candidates, ferns are far and away the most likely as the main
ground cover in the Morrison area.

[And, given a proper facies analysis of the distribution of fossil
pkants from the Morrison, it should be possible to reconstruct the
actual distribution of vegetation fairly accurately - though as
far as I know this has not yet been done].

swf@elsegundoca.attgis.com              sarima@netcom.com

The peace of God be with you.