Hi Oliver
Yes this is a bit of a gray area.
Sub-Species  ~  Variety / Variant   ~   Form

Generically Speaking:
Since we are not dealing with higher taxa such as Homo Sapiens the rules are
allowed to vary a bit.  Lower Taxa such as Mollusca have such diversity and
variation that before genetics we were left to morphological mercy.

Just as in humans, populations get isolated and breed them selves into very
seemingly different forms or varieties, thus our many ethnic groups.  The
theory is that with more time you eventually get separate species and then can
end up with (Panamic) cognates such as are common on each side, east/west, of
Central America and Mexico.

There is a straight answer bit it too ultimately ends up a bit gray.  One
author may consider it a species, an other a sub-species, and another a variant
or form.

I heard of one genetic study done on the west coast of the Americas.  A
particular Muricid which has server species names from California to Ecuador
was chosen.  The DNA sampling was done on population to population across the
entire range.  There was never enough genetic differ Nance from one population
to the next to consider it a different species.  However, it you take big jumps
down the coast and compare that DNA it becomes more arguably different enough
to be a different species (in theory)

The biggest problem is on this one was there does one species end and the other
begin?

So, have I thoroughly not answered your question?

Leslie

By the way, on our last US Census form, we certainly had people mark their
variety.  And no matter what they say the world is not flat, it is convex with
honey comb shaped sides... and pigs fry.


Please, ConchLers, could you explain the differences between a susbspecies and
a variation?

In human species, according to the general agreement, there is just one
species, and maybe no subspecies, but what about variations?
The criteria to variations, in shells, seem belonging to physical differences
(tall or flat spired, spiny or knobby etc...) and for humans???? Clearly
explaining why the human species only own variations (with or without
any "taxonomic value") might lead to destroy the old racist theory, or what? (a
dream, because, for example, the flatland society still exist!)...

Or am I wrong with my concept of variant?

I'm lost!!!

Olivier Caro, in the
dark.