Re: Coiling Parameters

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Dave,

You might want to check out the Macintosh application "MacRaup".

Although written in 1987, it still is a useful and simple way of 'getting
the feel' of coiling parameters. The program says it was written by

"Earl Shapiro and W Bruce Saunders, Dept of Geology, Bryn Mawr College,
Penn. 19010, USA"

And ported to the Mac by

"Richard Cowen, Dept of Geology, University of California, Davis, Calif.
95616, USA"

It is based on Raup's original paradigm, and lets you manipulate W, D, S
and T. It also has default Nautilus, Gastropod, Bivalve and Brachiopod
settings; and like all good Macintosh applications is mind-numbingly simple
to use. Just lauch like any old application, and enjoy! It works best on a
System 6 to System 7.1 Macintosh...it seems to crash on System 7.5.3. It is
a tiny program (less than 50 k). I can e-mail you a copy; or perhaps you
might want to contact the authors?

Since I work on heteromorph ammonites, specifically the Hamites -
Turrilites sorts of beasties; my interest in your work is more than
incidental. The real problem, as I see it, is not understanding the sorts
of shells Takashi Okamoto looked at; but rather the more 'phasic' ones.

By this, I mean, he looked at shells with a more-or-less constant shell
shape. Even a Nipponites is a constant shape, if an odd one. Ditto
Turrilites, Sciponoceras and so on. More perplexing are those with sudden
changes, like Hamites, where the shell description in the genes was very
loose, and the resulting form varies within the population. Also, how about
those with one form when young and a different one later on: Scaphites,
Ancycloceras, Hamites.

In other words, while a Nipponites could have done much the same thing
throughout its life, was this true for Hyphantoceras or Hamites?

Since my PhD project is on mode of life, this is quite relavant, but I
reached a bit of a dead-end with the modelling of growth. So good luck! and
hope it works.

Regards,

Neale.


>From  Neale Monks' PowerBook, at...

Department of Palaeontology, Natural History Museum, London, SW7 5BD
Internet: N.Monks@nhm.ac.uk, Telephone: 0171-938-9007