Re: Spinosaurus

["Tim Williams" <T.Williams@cclru.randwick.unsw.edu.au>]

Rob Meyerson wrote: 
 
> As an aside, there was an idea presented at the last North-Central GSA
> meeting, which may close the door on the idea of a "sail-backed" theropod
> (as well as any assumed flexibility of the spines).  By comparing animals
> with large neural spines, he found that those with thin, needle-like spines
> supported a sail, while those with broad, flat, and blade-like spines were
> used to support a hump of some kind (similar to camels and pigs).  If
> Spinosaurus carried a hump, then the spines would be rendered effectively
> inflexible.  Who knows, perhaps Spinosaurus was the camel of it's day?

I've heard this idea bandied around for _Ouranosaurus_ - converting 
this fellow from an anorexic-looking, sail-backed animal into a more 
chunkier creature with a fat-laden, camel-style hump running down its 
back.

I've also come across the notion that the tall neural spines of 
_Acrocanthosaurus_ may have been buried in a thick ridge of muscle.  
In _The Dinosauria_, the chapter on Carnosaur Paleobiology (?Molnar 
and Farlow) suggested that the anterior spines of _Acrocanthosaurus_ 
may have supported an "epaxial musculature" that functioned somehow 
in raising its neck and head.  

But the spiny ridge of _Spinosaurus_ is so HUGE.  (The spines of 
_Becklespinax_ are not too far behind.)  Such a hump would have been 
enormously top-heavy.  So, in case you hadn't noticed, I'm not too 
keen on a hump- backed _Spinosaurus_.  For _Ouranosaurus_, sure.  
(I'd love to see the illos of this!).