Dear all,
I tend to disagree.  When thorough revisions of a group are completed the
trend is usually as follows:  Some older names are indeed synonomized with
each other leading to a reduction in recognized taxa from the literature.
However, if the researcher is wise enough to check various museum
collections or actually do field work, numerous unrecognized, formerly and
incorrectly synonomized and/or previously uncollected species are located,
leading to an OVERALL INCREASE in the number of taxa in the group.  This
has happened time and time again in poorly or misunderstood groups.  I'm
not saying that this would happen if someone monographed the Strombidae
again.  Look at what's happening to the eastern US unionids.  Names are
being brought out of obscurity at a dizzying rate.  This will soon happen
with the Pleuroceridae of the SE US.  And don't even get me started on the
relatively few land snail groups that have thoroughly reviewed.
 
In short, I personally believe that we have barely scratched the scratch on
the surface.  100,000 is probably a low estimate, but in the case of
tropical land and freshwater (at least the micros) snails, we probably
won't get many collected before they are extinct.
 
Comments?
 
Kurt
 
 
At 10:05 PM 10/28/98 PST, you wrote:
>Dear Paul, dear others
>
>there might be about 120. 000 of counted names, but some
>of them are surely synonyma, so it's hard to get out how many
>species there are in realty without counting exactly and to have
>studied the synonyms. So I think there shuld be less than 100.000 species.
And I think splitters will have more species.
>with best shelling greetings and waiting for the 100.001th
>species
>yours sincerly Helmut Nisters
>
>----------
>> Hi Carol,
>> When I took undergrad invertebrate zoology, most of the textbooks
>> stated that there were "somewhat over 80,000 described species of
>> Mollusca".  However, that was shortly after mollusks were discovered.
>>  Most of what I have read recently puts the number somewhere between
>> 100,000 and 120,000 described species.  Of course, not all of them
>> have shells, but most do.  The same old textbook says there are an
>> additional 35,000 described fossil species.  I wouldn't be surprised
>> if that number has increased by a factor greater than that of the
>> living species.  The mollusks are the second largest phylum of
>> animals, exceeded in numbers only by the Arthropods.  Of course, the
>> Arthropods get top billing largely thanks to the inclusion of that
>> one mega-class of animals we all know and love so well - the insects.
>> Paul M.
>>
>