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Re: Parrish's neck work ...



Ronald Orenstein wrote:

> I have always assumed that these teeth would be quite useful in stripping
> leaves from branches - you can get a similar effect by drawing a leafy
> branch through a garden rake (or, better yet, use two garden rakes in
> opposition).

Yes, the sauropods were not only the longest, tallest, and most massive
terrestrial animals, but they may also be credited with being the first to 
exceed
the speed of sound (with their tails), and with inventing that hallmark of the
suburban lifestyle, the rake.

> Which raises the issue - how do you knock down a tree?  Surely the easiest
> way for an animal like this is to rear, plant your front limbs against the
> trunk and bear forward.  Seen this way, an unsteady rearing posture might
> be no problem if all that was required was to get into position before
> yelling the sauropod equivalent of "timber!".

> One anatomical feature you did not mention: the claw on digit I of the
> manus, the only claw sauropods retain (and I gather even that is missing in
> some Cretaceous forms).  It would seem reasonable to assume that this claw,
> when present, had some function, perhaps defensive - but if so it could
> only have been useful if it could be brought into play.  I suppose this
> could have been accomplished by lifting the forelimbs one at a time, but if
> the animals could rear it may have been even more effective.

Perhaps a reared up sauropod could jab its foot spikes at a predator; or perhaps
the sauropod could come slamming down onto a predator, throwing its considerable
weight behind the spikes.  In addition, the spike would have been useful to a
sauropod bracing itself against a large tree trunk to feed, or, as you suggest,
the spikes could help the sauropod secure itself to a slighter tree trunk to
facilitate pushing it down , either to feed itself or its chicks.

>  Perhaps its
> loss in later forms may reflect loss of rearing ability (which in turn -
> and here goes a wild, completely unsupported speculation - might have been
> less necessary as plant diversity - and particularly angiosperm diversity -
> increased at ground level(???)).

How do the jaw strength, dentition and tooth wear compare between the earlier
spike-footed sauropods and the later unspiked varieties?  How does the center of
balance compare?  How do the tail chevrons and neck mobility compare?  What 
plants
made up the dominant flora at different heights?  These factors should all play 
a
part in any evaluation of hypothetical diets and feeding postures for sauropods.
Anyone?


-- Ralph W. Miller III       gbabcock@best.com