>I recently received as a gift a dead large sinistral whelk.
>Incontrast to my other large one, this one has the double curve, as
>shown on the aforementioned site (that of the Jacksonville club).
>Is this the distinguishing feature of perversum?
>
>P.S.   I finally bought a digital camera so will soon be able to
>photograph  shells that I need help with i.d.

The paper defines all living sinistral Busycon as one species, B.
perversum. Though some still dare to defy me in this, I consider that
B. perversum must also include the "extinct species" B. contrarium
and dextral Pliocene-Pleistocene B. rapum (Heilprin 1887), which two
differ only in chirality (coiling direction). Once the living dextral
forms are examined I am confident that they too will fall under
synonymy of B. perversum (they had BETTER). Use subspecies-level taxa
at your peril.

"B" planulatum (Dall 1890), which also occurs in the Florida
Plio-Pleistocene, I think is not a Busycon, and despite Olsson &
Harbison 1953 it does develop a clearly-defined sutural channel just
as does B. pyrum, but belongs in Busycotypus/Fulguropsis (which
genera I hope someone is going to look hard at and soon, because I'm
pretty sure the latter is a synonym of the former). It also shows a
well-defined columellar plait and groove, which is not generally
evident in Busycon.

"Classically" what was once thought to be B. perversum is the heavy
low-spired conical Campeche Bay form with large well-spaced
peripheral spines and a swollen spiral ridge around the base of the
broad canal; the dextral equivalent of this morph is what has been
known as B. eliceans or "Kiener's Whelk" from the Carolinas. These
shells differ from the other extreme endmorph, which has a much
narrower canal lacking the fold, and often a taller spire and many
small close-spaced peripheral spines.... but wait, all of these
characters overlap and just about any combination of characters can
be found with a large-enough collection.

Don't spend ALL of your time playing with the camera... it's all too
easy to do so!

Or ELSE!
--
Andrew Grebneff
Dunedin
New Zealand
Fossil preparator
<[log in to unmask]>
Seashell, Macintosh, VW/Toyota van nut

: > P

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