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Re: (sigh)sauropod necks again--long!



Dr. Clay said:
"Okay, I know you were all hoping this thread was dead and buried
..."

Actually no.  It's good to see some sauropod stuff "rearing" its tiny
head again.  What you said was very interesting.  I was vaugely
familiar with the siphon idea you talked about, and now I feel I have
a better understanding of that concept.

It appears that some sauropods (diplodocids in particular) did have
their centers of gravity over their hips, which would appear to be a
decent location for a "pivot" for rearing up.  I don't think the
neck/head blood pressure thing is as big of a deal as some make it out
to be because sauropods have tiny brains, unlike giraffes which have
much larger brains.

The key to understanding rearing, in my humble opinion, is
understanding what is going on at the hips and the tail.  Can the hips
rotate back far enough to allow the sauropod to go tripodal?  Could
the tail support the sauropod tripodally?  Could a sauropod stand on
just its hind legs?  What of the caudofemoralis longus muscle which
runs off the tail and inserts on the middle of the back of the femur
on a landmark called the fourth trochanter?

I am planning on addressing sauropod rearing to a point in my
dissertation, and I am busy at work on a physical model (and hopefully
later a computer model) of the sauropod forelimb and hindlimb/tail. 
The forelimb model is complete, but the hindlimb/tail one needs some
work yet.  My hypothesis going into this is that the rearing in
sauropods is going to be limited by that C. longus muscle and how far
the pelvis can rotate back as the animal reared up.

When I get a chance, if anyone's interested, we can talk about
sauropod feet and how absolutely weird (and wonderful) they are.

Matt Bonnan
Dept. Biological Sciences
Northern Illinois University