BILLS at HSC.EDU
Mon Nov 8 15:55:00 CST 1999
Proponents of subspecies claim that additional information is provided by
naming populations within a species that seem to have limited gene flow
with other populations of the same species, and that can be distinguished
on the basis of some character or combination of characters.
I'm not a proponent of NAMING subspecies as such, and think that
information about differing populations within species can be better
explored in a narrative context. In any case, since we deal mostly with
museum material, any measure of gene flow is a guess unless some
electrophoretic or sequence data is available. Subspecies are usually
defined from museum material by a set of distinguishable specimens from a
specific geographic location that intergrades with other such specimens at
the margins of the subspecies' distribution. What do you do with the
intergrades? Well, some people use such clumsy designations as calling
them "Xus yus X zus intergrades." I doubt that the situation is made more
comprehensible by this procedure. A detailed analysis of variation in
polytypic species (and every species is perforce polytypic) is of much more
use than a proliferation of names.
A few people still try to name sympatric subspecies, a logical
impossibility. This doesn't always get caught on the way to publication.
Of course, you can argue about what constitutes sympatry.
The ICZN code recognizes subspecies names as coordinate with species names.
Thus if a "subspecies" is subsequently determined to be a full species,
that name can be raised in rank. Similary, a species name can be demoted
to subspecies status without change of authority.
The subspecies is not the same as the subgenus in status, however, because
most systematists use the BSC to more or less objectify the reality of
species. It makes little biological difference if a taxon is a genus or
subgenus, family or subfamily, but a great deal of difference if a taxon is
a species or subspecies. A species is an entity, but a genus is a concept.
Department of Biology
Hampden-Sydney VA 23943
email<bills at hsc.edu>
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