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"Lego my Stego" or Re: Plate movement in Stegasaurs



7/9/96 rstephen@cswnet.com Roger A. Stephenson wrote:

>Maybe I'm just too stuborn to let go of the notion that those plates moved,
>maybe not like a limb but in the subtle way a dogs hair lofts in intense
>situations. If  a color shift were to go along with these movements I can
>imagine the effect to be quite striking.
>
>Yeah, I know this is speculation, but I feel too much evolutionary effort
>went into making those plates to just have them hanging along their back.

Mickey Rowe replied:

>The comparison with dog hair isn't terribly appropriate.  The plates
>could easily change their radiative properties via pigment migrations
>and the selective opening and closing of the blood vessels feeding
>them.  Any flapping-mediated increase in heat transfer would be
>negligible in comparison.  Unless you propose that they spun around
>like fan blades...

What is this?!! Speculation coming from Joe Friday?!! I thought you were
proud to be a "just the facts" man. The facts don't seem to support the
flexing plates idea. They were more likely camouflage. Perhaps the Stego
had the ability of a camelion to blend in with it's environment with skin
pigmentation and the shape of the plates could make it appear to be a giant
bush. Perhaps when discovered by a predator the plates became an enflamed
color of red and that served to frighten a predator. Now there's some
entertaining speculation!

Are you planning to write a sequel to Raptor Red? "Lego my Stego" Bob
Bakker's not such a heretic after all, eh Joe?

[ I presume you're referring to Roger's message rather than my
 response?  If not, then let me clarify that by "easily", I meant in
 terms of what it would have taken to have evolved such abilities and
 what the abilities would have conferred upon the animals in terms of
 heat transfer.  So far as I know, there is no question about the
 plates being vascularized, and again, so far as I know, all vascular
 animals selectively shunt blood to different parts of their bodies in
 order to meet varying metabolic and thermoregulatory needs.  And
 although pigment migration a la chameleons and Octopus may be rare,
 lesser (and more relevant) pigment migrations are present in a lot
 of animals (even us). -- MR]

S.S. Lazarus