From our quarterly magazine The Strandloper (No. 257 March 1999) I found this piece of information:

" Wolrdwide, the authors consider that there are about 96 850 species of mollusc. This is devided up into 75 150 species of gastropod, about 20 000 species of bivalve, about 700 species each of Cephalopoda and Polyplacophora, and a mere 350 species of Scaphopoda"

M.J Gibbons et al. The taxonomic richness of South Africa's marine fauna: acrisis at had, S. Afric. J. of Science, vol. 95, 1999, pp.9-14.

Keep well.




********************************************
Regards, Groetnis

Kobie du Preez
********************************************
The Secretary/THE EDITOR STRANDLOPER
Conchological Society of Southern Africa
P.O Box 51694
WIERDAPARK
0149
South Africa

http://home.global.co.za/~peabrain
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>>> [log in to unmask] 07/23/02 03:59AM >>>
Dear WC;
        A perennial topic, but nobody seems to have any exact numbers, since i
don't think anyone is keeping track in a systematic manner, and
molluscan taxonomy is such a nightmare (especially for the more
multitudinous families such as Turridae!!) that even if someone WERE
trying to keep a semi-accurate count, it would contain many synomyms,
nomen dubium, etc.  I think there are more terrestrial spp than marine
by a modest margin, and there must be over 100,000 valid decsribed
species overall at the moment (3 or 4 new spp are assigned a moniker
(ie, are described) per day - even i have  a half-dozen spp i could be
writing up if i had a few more Round Tuits!), so that means perhaps
45,000 are marine, with at least 300 marine families.  i have no idea
regarding the proportion of Nudibranchs, Saccoglossans and other
shell-free marine spp, but it would not be a stretch to say there are at
least 35,000 described marine shell-bearing molluscs that could be
collected by a determined person with tons of cash to mount expeditions
to the far reaches of the World Ocean and a LOT  of time on their hands
- and probably another 10 to 15,000 undescribed spp without too much
trouble, for a reasonable total of 50,000.  In reality, collections with
over 20,000 marine spp are very rare.  Given the very poorly-sampled
diversity probably present in the myriads of  small-scale habitats in
the deep sea, and the fact that the pace of molluscan species decription
is speeding up rather than slowing down, i would personally not be
surprised if the total for marine molluscan spp eventually came in at
over 300,000 - ie, if we can get to them before they start going extinct!!!

        Anybody have more accurate figures or better guestimates than these
ball-park numbers??


From the cool, moist, VERY green land of New Scotland,
Ross Mayhew.

> Subject: How Many?
> Date: Mon, 22 Jul 2002 12:11:24 EDT
> From: William Corey <[log in to unmask]>
>
> Can anyone offer a figure on the present total number of Families and
> total
> valid species of marine mollusks (please cite reference ) ? WC Thanks.
>