The International Code of Zoological Nomenclature does not protect names
for hybrids. In other words, it does not encourage people to erect names
based on specimens that they know are hybrids. A "hybrid" is defined as
"the progeny of two individuals belonging to different species"--not
subspecies. If a species name is later proven to represent a hybrid, then
the name is not protected by the Code. To prevent confusion, the name
cannot be used again for any other animal, not even the parent species. Of
course, it's not easy to prove that hybrids are hybrids, especially when
they breed underwater.
 
Names for hybrids of plants are allowed under the Botanical Code. Plants
hybridize more readily than animals, and horticulturists usually know
exactly what the parent species are. Roses don't breed underwater.
 
Genetic material is traded asexually so often among bacteria, even bacteria
that are not closely related, that the bacteriologists have something quite
different in mind when they say "species". They operate under a separate
Bacterial Code.
 
Incidentally, hybridization can be another source of beneficial changes in
a group of animals, in addition to mutation. In the case of hybridization,
the raw material of the genes may be unchanged, but the combination is new.
So this is one of the sources of creativity in nature.
 
I think that we need to hear from some people who have some clear examples
of hybridization in mollusks, to give us a better idea of the concept.
Isn't the common garden snail of California a hybrid of two species, for
instance? Which two, and how and when did it happen?
 
Andrew K. Rindsberg
Geological Survey of Alabama