Hi to the sinistral people
I have hundreds of thousands of specimens in my land mollusc collection. I
have also examined at least an equal number in the field over years of
fieldwork. I also examined, and categorized into juvenile, sub-adult and
adult, almost two hundred thousand individuals of almost 100 species for the
Biogeographical part of my PhD. I have only ever come across a single
sinistral specimen. This was a Vallonia and I had a pleasent surprise when I
examined it with my microscope. Having looked at many examples of large
populations of, e.g. Theba, Cochlicella etc. and not having found a single
one, leads me to believe that sinistral specimens are not that common. Even
very abundant species, such as Achatina fulica rarely throw up a sinistral
individual (cf Tucker Abbott, 1989, Comp. where this is given as form
sinistrosa). These fetch very high prices on auctions and are quickly
snapped up by collectors (I confess to having bought a few myself).
Sinsitrality is related to genetics and early development (cf classic works
by Garstang). There is the odd reference to sinistrality in the older
literature (as for monstrosities) because these were highly sought after by
collectors, especially Victorians. I'm sure I must have left something out
(excuse the pun!).
Alex
-----Original Message-----
From: Conchologists List [mailto:[log in to unmask]]On Behalf Of
Stephanie Clark
Sent: 16 July 2006 21:37
To: [log in to unmask]
Subject: Must be sinistral month
Hi to Harry and other interested parties
I have a new species to add to the list of normally dextral species, having
a sinistral individual Lioplax pilsbryi (Viviparidae) before me.
Last Saturday (8 July) David Campbell (fellow conch-ler) and I were on a
day field trip sampling some spots on the Yellow and Pea Rivers in southern
Alabama and just into Florida. We were looking for mussels and hydrobiids
(freshwater snails, that those of you who attended COA this year learnt all
about!) in particular.
The spot on the Yellow River, where the specimen which is currently
crawling around under my microscope, was found was just east of Wing, in
southern Alabama. In fact I have visited this spot now three times since 22
December 2005, looking for a particular hydrobiid, to no avail. However the
first two times the river was more than a metre higher than it was last
Saturday, not to mention decidedly warmer. On all three occasions I found
Lioplax and Campeloma, crawling in the sand along the edges of the river, I
almost didn't pick any up, but they were in front of me so I kept a couple
for the record. I didn't notice the unusual Lioplax in the river, in fact I
thought I had picked up a largish Physa and thought nothing more about it
until the next day when I was checking the samples to label them and freeze
some of the material I had found. This is when I noticed that my big Physa
was in fact a small sinistral Lioplax.
This is now at least the second time I have found a sinistral version of a
normally dextral species in the last 10 months, the other was a hydrobiid,
but I will have to find the lot again, this one I noticed when I was
sorting some samples collected in the previous two years from Alabama and
Florida. When I relocate that lot I will let Harry and the rest of you know
what species that was. I had been meaning to send a note before about the
hydrobiid but having another live sinistral snail, has prompted my memory.
Stephanie
****************************************************************************
**
Dr Stephanie A. Clark
Biodiversity & Systematics
Department of Biological Sciences
School of Arts and Sciences
University of Alabama
Box 870345
Tuscaloosa, AL 35487
Phone: 1 (205) 348 1792 FAX: 1 (205) 348 6460
Mobile 1 (205) 310 9942
email [log in to unmask] or [log in to unmask]
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