Re: Platyhystrix and dinosaur humps/sails

["Larry Febo" <larryf@capital.net>]

-----Original Message-----
From: Dinochandler@aol.com <Dinochandler@aol.com>
To: dinosaur@usc.edu <dinosaur@usc.edu>
Date: Monday, March 06, 2000 8:43 PM
Subject: Re: Platyhystrix and dinosaur humps/sails


>Yes, most of the "sail-backed" dinosaurs lived around each other, too, like
>_Ouranosaurus_ and _Spinosaurus_.  Having a hump for a desert living animal
>would probably be advantageous, just look at camels.

(snip)

Back to
>_Dimetrodon_,  since it was a mammal-like reptile, it was probably
>ectothermic, and used a "sail" for heat acquisition.  Dinosaurs, on the
other
>hand...
>Anybody else have anything to add?
>


As far as Dimetrodon goes, I`ve always thought of it`s sail as a
"heat-dumping" mechanism. Especially if it was on an evolutionary path
towards increasing endothermy. They were rather large animals, and probably
lacked the sweat glands that were to appear in later mammals. ( I wonder if
therapsids had sweat glands??). Perhaps they were also used for heat dumping
in the aforementioned dinos. ...especially if these dinos were inhabiting
excessively hot enviornments, and their "avian style" respiratory systems
 assuming they had such) were alone not sufficient to cool these large
animals down.