[Taxacom] Principles (was: early extant angiosperms)

Kenneth Kinman kennethkinman at webtv.net
Sun Feb 21 04:25:32 CST 2010

Hi Barry,
       Is that your argument against giving formal taxon names to
paraphyletic taxa?  That the membership will vary?  So when you find a
new fossil that extends the scope of a taxon just a little, you have to
propose yet another name to accomodate it?   No thanks.  Class Aves
worked just fine before Archaeopteryx was discovered, and still worked
just fine when Aves was expanded to include it.  And now we have lots of
new fossil birds which fit nicely within even that relatively large gap.
       And that is a clade.  Your principles (strict phylogenetics)
don't allow formal paraphyletic taxa at all, no matter how obviously
useful they are.  If botanists (even strict phylogeneticists) keep
refering to a group like paleodicots (or alternately early-divergent
angiosperms, or basal dicots), why not have a formal taxon name for it? 
      Having a taxon (holophyletic or paraphyletic) expand its
membership to incorporate new taxa is a small price to pay compared to
the HUGE price we will pay when we are overwhelmed by a flood of new
clade names and their often convoluted phylocode definitions.
Barry wrote:
HI, Ken, 
Not being a botanist, I can't comment on the individual taxa involved,
but only on the principles.  Perhaps "basal dicots" (or the like) is a
useful, informal, descriptive term.  There will always -- by
definition -- be "basal dicots," but the membership of that group (or,
rather, our understanding of it) will vary depending on the phylogeny
accepted at a given time.  This is not what you want to happen with a
formal taxon name.  So yes, I think we arrive at the same conclusion,
just by different routes.   Barry 

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