[Taxacom] Taxonomic challenges at species level
kennethkinman at webtv.net
Tue Jan 27 21:00:11 CST 2009
Hi Richard Z.,
I totally agree. And I think a majority of the disagreements
between lumpers and splitters today (at the species level, or any other
taxonomic level for that matter) are the result of unnecessary attempts
to rectify the perceived "paraphyly problem", which in my opinion only
exists in the minds of those who accept the simplistic dogma that
paraphyly is automatically unnatural and must be attacked.
What is even more exasperating is that some of the "strictly
cladistic" dogmatists lump the daughter/autophyletic taxon into the
mother taxon, while others oversplit the mother taxon down to a level
where some subtaxon can then be sister to the daughter taxon. I don't
like either of these extremes, and prefer the middle ground approach
(placing a marker within the mother taxon showing which subgroup is
sister to the daughter taxon). At species level, such subgroups are
subspecies or populations within the mother species (or ultimately even
a single individual or mating pair in many cases with the founder
effect, although we obviously have no way to document such individuals
that almost always rotted away with no fossil remains).
At class level, we have examples like Class Aves, probably having
a sister group at family level within the dinosaurs (or as they now call
them, "non-avian dinosaurs", since they can't stand the thought of a
paraphyletic Dinosauria). Cladistic "analysis" has certainly done much
to elucidate the phylogeny of dinosaurs and other taxa as well, but that
doesn't mean strictly cladistic "taxonomy" is somehow superior. For the
vast majority of taxa, strict cladistic taxonomy is actually inferior
and causes needless confusion and unstable classifications.
PhyloCodists can't even agree on whether Archaeopteryx is part of Aves
(a subgroup of PhyloCodists want Aves to apply only to the living crown
group). PhyloCode is a bureaucratic free-for-all that is the
culmination of strictly cladistic excess. If it goes much beyond
Herpetology, we are in for a hell of mess. I believe that a "mostly"
cladistic taxonomy, with appropriate and occasional paraphyletic breaks,
is what we really need, but the opposite extremes still seem more intent
on fighting each other than admitting that such a compromise is
Richard Zander wrote:
I think rapid speciation with survival of the parent species is
common. In paraphyly, doubtless one of the species in the paraphyletic
taxon is an ancestor of the (let's call it) autophyletic taxon. Why
postulate an additional ancestor species different from an extant one?
It's not parsimonious to do so.
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