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Re: Mamenchisaurus neck posture

I've read the archives for a long time, however as an amateur, I was
reluctant to post.  I've always wondered about this theory of sauropod neck
elevation though...if they couldn't raise their heads above heart level,
wouldn't this exclude them from walking up hill?

> From: GSP1954@aol.com
> Reply-To: GSP1954@aol.com
> Date: Wed, 09 Jul 2003 22:52:03 -0400 (EDT)
> To: dinosaur@usc.edu
> Subject: Mamenchisaurus neck posture
> Recently a Sino newspaper article was posted mentioning some Chinese
> researchers analysis that Mamenchisaurus could not lift its neck and head far
> above 
> heart level (anyone know if there is a technical study out on this?). This is
> perplexing in that the quarry map of a complete Mamenchisaurus in Pi et al
> 1996 
> shows the apparently articulated neck flexed dorsally so that the head is far
> above the back. This is a death pose, but there is no a-priori reason to
> presume the neck could not approach or match the same position in life in the
> manner living people and other animals can tilt their head back into a death
> pose. 
> The two giraffe necks I have articulated articulated in a sub horizontal
> posture, but giraffe's can lift their necks vertically. Also, the quarry photo
> of 
> the  Mamenchisaurus in Yang et al 1972 shows the neck kinked up at the base
> even though the rest of the neck was not dorso-flexed, further evidence that
> the 
> head was often carried well above heart level.
> If as some argue blood pressure issues kept sauropods from elevating their
> heads well above heart level then they would have strong stops in the
> cervicals 
> to keep the head from being raised so high that circulatory disaster would
> ensue. In reality only the short necked dicraeosaurs had such necks, all long
> necked sauropods had the ability to elevate the head many meters above the
> heart 
> even when quadrupedal - even more so when rearing which many sauropods were
> specialized for doing. Ergo most sauropods had the ability to stand far taller
> than any known mammal, which in turn should have required oversized, super
> pressure and hard working hearts that would have boosted metabolic rates well
> above reptilian level.
> GPaul