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RE: Protoceratopsoid tails adapted for swimming

To clarify something.

The Djadokhta Formation is primarily deposited as a braided river, interdune 
facies with aeolian deposits. There are mudstones as well as sandstones. The 
Djadokhta produces not merely the famous Flaming Cliffs and Ukhaa Tolgod "egg 
beds" sites, but also a host of an aquatic biota, including ostracod 
crustaceans and molluscs, as well as aquatic crocodilians: *Shamosuchus 
djadochtaensis*, for example.

It is not unreasonable to assume that some dinosaurs swam, nor that some 
dinosaurs have become secondarily aquatic. But the problem with Terenschenko's 
hypothesis is not that the environment seems infeasible -- it is not -- but 
that the skeletal morphology seems out of keeping with this habitus. The tail 
alone suggests that inferring a sculling tail function doesn't work, but there 
is some attempt it seems to discount how a sculling tail isn't required, but 
the tail morphology -- sometimes terms a living "billboard" -- still enables 
this: High basal mobility, tail spines, some mechanical advantage the 
inter-spinous muscles give to lateral mobility, etc.

If you need to argue against this hypothesis, use the data Tereschenko himself 
provides -- or in some cases doesn't.


  Jaime A. Headden
  The Bite Stuff (site v2)

"Innocent, unbiased observation is a myth." --- P.B. Medawar (1969)

"Ever since man first left his cave and met a stranger with a
different language and a new way of looking at things, the human race
has had a dream: to kill him, so we don't have to learn his language or
his new way of looking at things." --- Zapp Brannigan (Beast With a Billion 

> Date: Thu, 5 Dec 2013 10:47:11 +1100
> From: dannj@alphalink.com.au
> To: dinosaur@usc.edu
> Subject: Re: Fwd: Protoceratopsoid tails adapted for swimming
> On Thu, Dec 5th, 2013 at 8:57 AM, Michael OSullivan 
> <michael.osullivan@port.ac.uk> wrote:
>> or to live in a desert....yes, I will keep harping on this.
> You'd be surprised how many aqu
frican crocodile
> (*Crocodylus suchus*) comes to mind.
> http://news.nationalgeographic.com.au/news/2002/06/0617_020618_croc.html
> --
> _____________________________________________________________
> Dann Pigdon
> Spatial Data Analyst Australian Dinosaurs
> Melbourne, Australia http://home.alphalink.com.au/~dannj
> _____________________________________________________________