Re: Ankylosaurs and "mimicry"

[ornstn@hookup.net (Ronald Orenstein)]

>
>A very unusual paper has come out from Tony Thulborn:
>
>Thulborn, Tony. 1994. Mimicry in ankylosaurid dinosaurs. Records of the
>    South Australian Museum 27(2):151-158.
>
>Tony's paper is facinating and thought-provoking, although that's not
>to say he's convinced me. Ken Carpenter reviewed it, so his comments wouldq
>be of great interest. In the paper, he suggests the tail club in Late
>Cretaceous ankylosaurids was not the defensive weapon most of us supposed
>it to be because of limitations in the movement of the tail in those forms.
>Instead, he suggests it served as a mimic of the beasts head to draw
>attacking theropods to the wrong end of the animal. He includes a figure
>of a grazing anky with the tail sticking up at a 25 or 30 degree angle and
>notes how similar it looks in profile to a quadrupedal posturing Iguanodon.
>As such, it would be the first case of dino mimicry. My intuition is that
>theropods would not fall for it but it's a thought-provoking paper. As you
>probably have guessed from past postings, I have a soft spot in my heart
>for those trying to throw monkey wrenches into conventional dogma, and Tony
>is good at that and a very bright guy. It's worth a look.

The trouble, of course, with speculation like this is that it is utterly
untestable - in fact, it's hard enough to determine cases of mimicry (as
opposed to simple resemblance) in LIVING animals!  Thus, Owl Butterflies
(Caligo) were supposed to mimic owls - but this would only work if they sat
upside down with their wings opened, and they don't.  Lantern flies were
supposed to mimic alligators (though any bird that would be frightened off
by an alligator a few centimetres long in the top of a tree would seem to be
one of nature's failures to start with).

Actually, I seem to recall someoner proposing a few years back that ankylo
tail clubs could not be weapons because their bony tissue was so highly
vascularized as to render them too brittle for such use; the suggestion was
that they were somehow involved in heat exchange.  Any comments on this?
--
Ronald I. Orenstein                           Phone: (905) 820-7886 (home)
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