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Bounding *Thecodontosaurus* (was Re: Eustreptospondylus Q's)



   I'm not sure if the best example of this condition is
*Thecodontosaurus*, because it is not represented by the greatest
material; according to the Prosauropoda section of  *The Dinosauria*, the
restored skeleton of *Thecodontosaurus* belongs to a juvenile
approximately 1 meter in length, with adults possibly measuring about 2.5
meters in length.  It's possible that juveniles of *Thecodontosaurus* had
very different limb proportions from adults, i.e. arm length increasing
relative to leg length. Either way, a 2.5 meter long adult of
*Thecodontosaurus* probably was more than a little larger (heavier) than
a big hare.  
   If we use slender forearms and very long hind limbs as a starting
point for looking for bounding possibilities, I agree that juvenile
*Thecodontosaurus* fits well.  Also, certain members of Protoceratopidae
(or basal members of Neoceratopia, depending on one's opinion on the
monophyletic status of Protoceratopidae) appear to fit fairly well.  For
example, *Leptoceratops* has those disproportionate limbs and was
probably partially quadrupedal.  But, then again, *Leptoceratops* and
allies may have foregone the bounding and just ran on their hind legs. 
For that matter, the limbs of *Protoceratops* have that look to them, but
because of the size of *Protoceratops* I find the idea of rabbit-hopping
*Protoceratops* more funny than serious.  I wish pachycephalosaurians
were better known. 
   Let's not forget heterodontosaurids, either.  They seem to be better
suited for bounding than *Thecodontosaurus*, aside for quadrupedality.  I
like the idea of them walking on all fours and running on hind legs. 
Anyone have any other candidates?

   Happy New Year's to everyone!-*Thescelosaurus*      

On Thu, 31 Dec 1998 21:14:49 -0800 (PST) "Jaime A. Headden"
<qilongia@yahoo.com> writes:

>  Depends on the animal. The longest legged quadruped I can think of
>is *Thecodontosaurus*, and while the bones of the forearm are slender,
>I don't beleive they are as strait as required for the process. And I
>think the hand was wrongly constructed, but I may be wrong. However,
>there are a few other small animals with more slender hands that may
>be more compatible. Greg Paul did an excellent short study on the
>bounding possibilties of *Marasuchus* most easily demonstrated by the
>slender forearms and very long hind legs, as in rabbits, frogs, and
>*Thecodontosaurus* (and *Scleromochlus*) (Paul, 1988). The
>biomechanics may differ on the results, but mass is not entirely
>restrictive of the process, as *Thecodontosaurus* was probably only a
>little larger than a big hare.


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