Re: [Re: Sauropod Trunks]

["M.Alan Kazlev" <akazlev@kheper.auz.com>]

archosaur@usa.net wrote:
> That's all well and good for animals like Camarasaurus
> and Apatasaurus, but
> what about Brachiosaurus. Having it's neck held out more or less horizontally
> just doesn't seem to make sense (not with those forelegs at least)
yes i agree Brachiosaurus' long forlimbs would have indicated a neck held
higher off the ground than in the case of the diplodocids etc.  But
that still doesn't mean the neck would've bene held in a swan- or a giraffe
- like posture (perhaps at, say, a 33 degree angle, but not as erect as
a giraffe?)
> Also wouldn't a head that is held up like a giraffe
> put less strain on the
> muscles since you wouldn't have all that weight sticking out way in
> front, or
> is this where the small sauropod heads come in.
Well apparently (i'm just going by what i read - being no expert myself)
the structure of the vertebrae (neural spines etc) do not indicate attachment
for giraffe-typoe muscles or tendons.
> Again, I can understand the whole horizontal bit
> with animals that have long
> tails like diplodocids and camarasaurids. Their tails having the tendons
> that
> cantelever their necks and all, but what about Mamenchisaurus and Brachiosaurs
> with their (comaratively) small tails. In cases like that, I could
> understand
> the more erect position of the neck.
Even if we allow the problem of short tails in brachiosaurs etc (&
i _don't_ think this is such a serious problem - the tails were
short only relative to diplodocid tails, they were still fairly long) still
doesn't answer the problem of how blood could be pumped up so high against
the force of gravity.  Hard enough for a giraffe - the pressure to
pump blood to the head gives them such high blood pressure in the limbs
they need a special hardening in their legs so their blood-vessels don't
burst.

There has been some interesting work done recently on sauropod posture & neck dynamics.  It was inan issue of Discovery magazine which unfortunately i dodn't buy so I can't quote u, but the guy ran computer simulations of sauropod skeltons.  i think he said camaraosaurs could hold their necks fairly high (giraffe- or swan-like?), brachiosaurs at a diagonal, & brontosaurs & diplodocii had their necks out horizontally (which supports your tail counter-balance hypothesis).

Hmm, have to try to chse this article up....

 

Archosaur J

http://members.tripod.com/~jurassosauridae/index.html

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