RE: Dino Mimicry

[Ralph Chapman <MNHAD002@SIVM.SI.EDU>]

Just a few more thoughts on dino mimicry:

1) It actually isn;t true that the idea is not-testable. True, we cannot
observe it now but there are ways of framing the question within the context
of functional morphology that would serve as de facto testing. The best
proponent of such things these days is Dan Fisher of Michigan who's
ineluctable logic was able to demonstrate quite soundly to the paleo
community that the mesozoic horseshoe crab Mesolimulus (Solnhofen) swam
upside down (like modern horseshoe crabs) at a specific speed range and
at  a calculated angle with the air-water interface. It's an astounding
paper and, amazingly, not atypical of Dan's work. He's in the process of
decimating the calcichordate theory of chordate origins right now, as well
as doing amazing things with mastodons and mammoths. The process would take
a very rigorous framing of the hypothesis to be tested with a series of
detailed modelling and logical deductive logic. It's tough but quite
doable and is one of the reasons functional morphology has seen a rebirth
over the last 15 or so years. Dan also was able to demonstrate, by the way,
that the Mazon Creek horseshoe crab Euproops actually had sub-aerial
excursions in its behavioral repertoir as well. I wish I was a good enough
functional morphologist to do this type of work but it really hurts the
brain to do it. I'll stick to what I'm better at but will try at times
to do some.

2) I guess one way to try and do 1) above for the mimicry possibility
would be to do extensive and detailed modelling of the excursion limits
of the anky's tails to see what movements really are possible there.
Thulborn says they are limited and could not be effective defensive weapons
which I guess means they could not be swung widely from side to side.
If true, what other defensive strategies would work with it? Maybe, if mimicry
was a possibility, the mimicry pulled the theropod toward the tail -
close in enough to allow some bapping (note extreme scientific technical term
here) of it within a more constrained arc or something. Maybe some help
at odd times such as dusk/dawn and evening is enough to justify having a
mimicry component. So many things to work on - all depending on detailed
anatomical and functional work. The paper got some of thinking, though, which
is its primary job.

I'd like to thank Ken for being an open-minded reviewer. I wish more were.
I try to be and mostly succeed. Shame about the Behavior conference volume
of Horner's. I have a paper on dino footprint morphometrics that is the
basis for a real detailed study by myself, Diego Rasskin, Moratalla and Sans
that will be done within a few months. I'd would have been nice to have that
out beforehand.

Anyway, I actually think this problem is "testable" and would be an
interesting project to see done, especially with the detailed analysis
of anky tail excursion limits.

Yours functionally, Ralph Chapman NMNH