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Re: Diplodocus: Return to the Swamps????



Although I don't have a dog in this race, this thread reminds me of the 
taphonomy one of the larger specimens of the sauropod _Giraffatitan brancai_.  
The humerus and a tibia of this specimen (SII) were preserved in an upright 
position.  This led Janensch (1914) to adduce that the individual had been 
mired in soft mud before burial.


This was at "Tendaguru Site S", as discussed by Heinrich (1999) in his summary 
of the taphonomy of the Tendaguru dinosaur locality.


Cheers

Tim


--- On Sun, 12/13/09, don ohmes <d_ohmes@yahoo.com> wrote:

> From: don ohmes <d_ohmes@yahoo.com>
> Subject: Re: Diplodocus: Return to the Swamps????
> To: dinosaur@usc.edu
> Date: Sunday, December 13, 2009, 10:35 PM
> --- On Mon, 12/14/09, Jonas
> Weselake-George <Paleo@ncf.ca>
> wrote:
> 
> > From: Jonas Weselake-George <Paleo@ncf.ca>
> > Subject: Re: Diplodocus: Return to the Swamps????
> > To: dannj@alphalink.com.au,
> dinosaur@usc.edu
> > Date: Monday, December 14, 2009, 1:13 AM
> > 
> > Dann Pigdon <dannj@alphalink.com.au>
> > wrote:
> > "It goes in splayed with plenty of resistance
> (limiting the
> > depth of penetration), but is drawn out with converged
> toes
> > that offer far less resistance. Sauropods, on the
> other
> > hand, would have had to fight each step to extract a
> foot
> > from deep mud. That's bound to tire a large animal out
> after
> > a while."
> > 
> > What about taking into account mass (and muscle mass)
> vs.
> > limb surface area? It would seem to me that a fifteen
> ton
> > sauropod would experience less relative suction than a
> one
> > ton theropod. What do you think? 
> 
> Exactly. Re is critical (or perhaps some related but more
> situation-appropriate and specialized metric). Mud is
> essentially less dense/viscous for larger animals...
>   
> > Additionally, the sauropod would tend to punch through
> to
> > the substrate more easily and would also have four
> limbs for
> > balance. I'm not arguing that it'd be easy, but a
> large
> > sauropod might have an advantage in moving through a
> swamp
> > (not that it is very likely a theropod one fifteenth
> its
> > weight would have a motivation to follow). 
> 
> Don't forget that repeatedly sheared mud tends to liquify.
> In other words, if you have the power to shear it in the
> first place, it becomes easier w/ each shearing. And less
> supportive to any splay-footed interloper. 
>  
> > A more likely situation would be sauropods taking
> advantage
> > of the mud to mate (after all I saw a paper suggesting
> that
> > an early cretaceous ornithopod population was using
> swamps
> > for shelter during the breeding season).
> 
> What is unlikely about a theropod-free zone?
> 
> Anyhow, to bed for me...
>