Re: Physiological Adaptations of the Dinosauria (long)

["Waylon Rowley" <hot__male60@hotmail.com>]

to: "Rob Gay"
from: Waylon D. Rowley


> Allow me to interject for a moment here:
> From what I have seen (pictures and drawings) of _D. sinensis_, the crests 
> are apx. the same size as that of _D. wetherilli_ (a little >bigger, but 
> negligible). However, they appear to be much thicker than >_D. wetherilli_, 
> and I would think that you would want thin vanes if >you were going to be 
> using this structure as a radiator. But if we were >going to discuss crest 
> vs. total skull size, I would think that >_Syntarsus kayentakatae_ would 
> have the largest proprtional crest, >being apx. 40% of the length and 21% 
> of the height of the skull, plus >having an antobrital fenestra almost as 
> long and twice as tall. And, >this is almost contra your argument, but most 
> coelophysoids have >huge< >antorbital fenestrae, covering in some cases 
> almost 45% of the length >of the skull.

Unless you know something that I don't, the specimens of D. wetherilli
were preserved *without* crests, and they used D. breedorum (which does have 
crests) to fill in the gaps in our knowledge on D. wetherilli's crest 
morphology. Check out this link: 
http://dinosauricon.com/images/dilophosaurus-am.html
Since I lack any knowledge of D. breedorums crest height, length, and width, 
I opted for ?D. sinensis for which I have seen pictures of at least.




> In coelophysoids that had crests, most of the crest was composed of the 
> lacrimal, or even a seprate bone, as posited by Welles (1984), so
> positioning might be questionable for this function.

In that case, we need to know whether this "separate bone" has foramina for 
the superior nasal artery.


> This is a hypothetical _Eucoelophysis_ that you speak of, right? Because 
> _E. baldwini_ wasn't similarly-sized.

I'm talking about an E. baldwini that has been scaled up to ?D. sinensis 
size.


> Both of the areas mentioned here are what you propose
> for heat exchangers, so you have no neutral ground. You'd also need to take 
> a sample from some place like the illium or the scapula to see >if there 
> was a difference.

Good point. Unfortunately, I simply don't have the money nor equipment to do 
a study like this....so i'm going to leave it to the hands of more 
prestigious paleontologists (assuming they'd want to test my hypothesis in 
the first place.)
_________________________________________________________________
Get your FREE download of MSN Explorer at http://explorer.msn.com