Dear Rich and all; Thanks for your initial comments. I know many of you are
not land shell enthusiasts but this topic may raise some issues that go
beyond land snails to the naming of new forms of any type of shells. It
seems that, all of a sudden, virtually every shell species, especially the
popular ones, has numerous named forms, usually based on color pattern,
size, distribution or some other distinguishing feature.

Rich, as you state, Amphidromus perversus is an extremely variable snail in
shell size, shape, and color patterns. Many colonies exhibit wide variations
of all those characters. Laidlaw and Solem did make changes to the grouping
of A. perversus and it's affiliates. They also lamented that "much more
material must be reviewed...before any classification of this complex can be
called more than provisional".

Laidlaw and Solem's four choices for subspecific status of this group strike
me as rather odd: First they name a new subspecies, A.p. butoti, their
partial description being: "The general intensity of the coloration and the
strong polish are the only features separating this race from the other
subspecies". A.p. butoti are endemic to just one rather small island.

Two of their other three subspecies, emaciatus and melanomma are little more
than color forms. The fourth, A.p. natunensis is named for it's isolated
small island home. It comes in at least a few of the already named color
forms. I'd say there's still a lot of work to do on this group.

Here are some of the things that struck me as unusual about one of the two
forms that John separated out as distinct: A.p. kadatuaensis (proposed name)
Is endemic to Kadatua Island, off the southeastern tip of Sulawesi(Celebes).
What is remarkeable about this population is that virtually every single
snail looks just like every other snail. So much so that they could be
clones:

All are dextral
All are small, about 40mm long(give or take a couple mm's)
All have thin shells (unlike perversus)
All have the same "strigosus" color pattern
None of them has a varix
The aperture is proportionately larger than most perversus
The suture is only slightly indented, if at all, giving the shell a smooth
outline from tip to base. The shells are thus distinctly "tear-drop shaped"
(please refer back to John's photo).
The aperture is only slightly thickened, not flaring and difficult to say if
it is adnate at all.

This shell does not resemble any of the common perversus shapes. In fact I
have never seen this particular shape and would like to know if others have.
The only thing that really resembles A. perversus is the color pattern.

Rich, you probably have seen more A. perversus than most of us. Have you
seen this shape in perversus and is it localized or scattered?  Are there
any other  known populations of A. perversus where all the shells are so
similar to each other?

So here we have a population of Amphidromus that is different than any other
described population. It is isolated and thus surely evolving into something
other than typical perversus. Based on the criteria used in naming the other
sub-species of A. perversus, or based on other criteria, does this one
deserve it's own name?

The other shell John picked as being unique and deserving of a name has many
of the same characteristics as A.p. kadatuaensis and I'd be glad to share
the distinguishing features with anyone who is interested. Pete

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