Re: CROCODYLOMORPH ENDOTHERMY

["Nicholas J. Pharris" <pharrinj@PLU.edu>]

On Thu, 25 Jan 1996 Dinogeorge@aol.com wrote:

> In a message dated 96-01-25 03:02:00 EST, pharrinj@PLU.edu (Nicholas J.
> Pharris) writes:
> 
> >I'm not convinced that an ectotherm would need a four-chambered heart.
> 
> They don't. But four-chambered hearts permitted a higher level of activity
> and, by separating the pulmonary from the systemic blood circulation, also
> permitted the evolution of long, erect limbs and tall bodies. Details in
> Regal & Gans, 1980, article in _A Cold Look at Warm-Blooded Dinosaurs_.
> Endothermy came later--much later.

I'm also not convinced that ectotherms would need or could use "long, 
erect limbs and tall bodies," hence my suspicion that these features 
evolved in endothermic crocodilian predecessors (and that all other 
animals which show these feautures--other thecodontians, all dinosaurs, 
and all therapsids, including mammals--were/are also endothermic to one 
degree or another).

Nick Pharris
Pacific Lutheran University
Tacoma, WA 98447
(206)535-8204
PharriNJ@PLU.edu

"If you can't convince them, confuse them." -- Harry S. Truman