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Re: THERMOREGULATORY FRILL



Rob Meyerson posted a response to an article I posted on the list, regarding the
possible thermoregulatory role of the ceratopian frill. However, he failed to
indicate that he was replying to something written by a journalist, and not by
Reese Barrick or myself.

> [buzzing sound]
> Wrong, try again.  Mr. Barrick has convieniently forgotted the jaw muscles
>  that extended up into those holes.

As indicated above, Reese Barrick did not write the article. Some experimental
conclusions of his are merely included in an article written by a poorly
informed journalist.

> As long as we are on the subject of frill jaw muscles, does anyone know if
>  T-tops had a set of jaw muscles that extended to the top of the frill
>  (heck, was there any muscle up there)?  I know that the main jaw muscles
>  are held within and underneath the frill, but what about on the outside?
>  Just idle curiosity on my part.

The distal-most rim of the frill is unmuscled as far as I'm aware. It would be
covered with integument only.

> The frill-as-a-radiator hypothesis is a red herring.

You fail to appreciate that structures apparently adapted for a single function
are frequently used for others. The horns of artiodactyls, like those of
ceratopians, do not appear to be good devices for thermoregulation. However,
some of the following refs indicate the opposite.

GEIST, V. 1966. The evolutionary significance of mountain sheep horns.
_Evolution_ 20: 558-566

SPINAGE, C.A. 1968. Horns and other bony structures of the skull of the giraffe
and their functional significance. _East African Wildl. Jour._ 6: 53-61

STONEHOUSE, B. 1968. Thermoregulatory function of growing antlers. _Nature_ 218:
870-972

TAYLOR, C.R. 1966. The vascularity and possible thermoregulatory function of
horns in goats. _Physiol. Zool._ 39: 127-139

DARREN NAISH
dwn194@soton.ac.uk