Iselica is another genus, widely placed in the general vicinity of
capulids (typically as Fossaridae), but is actually a heterobranch
akin to Amalthina.

On Mon, Jun 20, 2011 at 7:16 AM, Harry G. Lee <[log in to unmask]> wrote:
> Brilliant - absolutely brilliant, David.
>
> I'll betcha you have Cyclothyca pacei Petuch, 1987. It seems to prosper on
> the shells of living pectinids and Spondylus americanus. According to the
> original description, in which the genus name is consistently misspelled
> "Cyclotheca," the favored "host" was reported as Chlamys imbricata [=
> Caribachlamys pellucens (Linnaeus, 1758) of yesterday's forum].
>
> Cyclothyca was placed in the Capulidae by Petuch, whereas the affinities of
> the much larger Amalthina tricarinata (Linné, 1767) seem to be with the only
> remotely-related Heterobranchia.
>
> But wait! I have just examined some juvenile C. pacei shells and discovered
> that, like the Heterobranchia, they are heterostrophic. That is, the
> embryonic shell is sinistral, and the axis of coil rotates through about 270
> degrees at the metamorphosis to the teleoconch. The shells of the two
> nominal taxa are in fact very close! So close that, allowing for differences
> in size, and accounting for the natural variability of shell form induced by
> irregularities of substrate topology, they could be the same species!
>
> I find it strange that a snail like Cyclothyca pacei has only recently come
> to our attention in SE Florida. Could it be that it is just an ecophenotype
> descended from an immigrant A. tricarinata? The latter is known to be
> associated with oysters and pen shells in Japan. Maybe, when introduced to,
> say, Biscayne Bay in bilge from one of the Japanese merchant fleet water
> sometime in the mid- or late 20th Century, it took up with the most
> available hosts in the vicinity?
>
> In any event the resemblance between "Cyclothyca" pacei Petuch and
> Cyclothyca Stearns 1890 [Type species C. corrugata Stearns, 1890] is
> infinitesimal compared to it and A. tricarinata.
>
> You have opened a Pandora's Box, David - mostly attributable to an eclectic
> taste in gastropod shells and a "photogenic" memory of iconographies.
>
> Harry
>
>
> On 6/19/2011 11:52 PM, David Kirsh wrote:
>
> Recently, I collected from drift in Boca Raton, Florida and came across a
> 4mm cap-like shell I thought I knew. The name had "tri-" in it, and possibly
> "Ama-" something...couldn't find it in Abbott (1974) or Colin Redfern's
> Bahamas book or Harry's Marine Shells of NE Florida. I felt slight
> shame..."I ought to know this one."
>
> As I was taking photos of it, my flash must have jarred loose that it is
> supposed to be parasitic on other shells. Somehow that led me to crack open
> Okutani's Marine Mollusks in Japan and there it was: Amathina tricarinata
> (Linnaeus, 1767).
>
> Now that I'm a little reassured that my memory isn't totally gone, I'd like
> to know if others have found this species in the western Atlantic.
>
> David Kirsh
> Durham, NC
>
> "It's no wonder that truth is stranger than fiction.
>  Fiction has to make sense." - Mark Twain
>
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>
> --
> Harry G. Lee MD
> 4132 Ortega Forest Drive
> Jacksonville, FL
> USA
> (904) 389 4049
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> [log in to unmask]



--
Dr. David Campbell
The Paleontological Research Institution
1259 Trumansburg Road
Ithaca NY 14850

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