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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: firstname.lastname@example.org
> To: email@example.com
> Subject: Re: Fwd: Protoceratopsoid tails adapted for swimming
> On Thu, Dec 5th, 2013 at 8:57 AM, Michael OSullivan
> <firstname.lastname@example.org> wrote:
>> or to live in a desert....yes, I will keep harping on this.
> You'd be surprised how many aqu
> (*Crocodylus suchus*) comes to mind.
> Dann Pigdon
> Spatial Data Analyst Australian Dinosaurs
> Melbourne, Australia http://home.alphalink.com.au/~dannj