Re: Platyhystrix and dinosaur humps/sails

[Bill Adlam <sagitta_elegans@yahoo.com>]

Jaime wrote:

>   *Platyhystrix*, as an amphibian, was cold-blooded
> and may have used the sail much as has been proposed
> for *Dimetrodon* and edaphosaurids, as a
> thermoregulatory device, to raise the mean body
> temperature, but this would actually increase body
> water loss in the amphibians (but purportedly not the
> synapsids (Carroll, 1988)), and that would not be so
> pleasureable, I think.

I'm afraid I don't know anything about _Platyhystrix_ beyond what's
been mentioned here.  In what sense is it an amphibian: crown group
amphibian, stem amphibian or stem tetrapod?  And how big is it?

Modern amphibians breathe through their skin, so a sail could increase
oxygen supply.  I can't remember any particular evidence for cutaneous
respiration in early terapods, but it would seem likely.  Perhaps 
someone more informed than me could comment...

Bill Adlam
__________________________________________________
Do You Yahoo!?
Talk to your friends online with Yahoo! Messenger.
http://im.yahoo.com