[Taxacom] Pteridophyta

Kenneth Kinman kennethkinman at webtv.net
Mon Jul 27 11:17:45 CDT 2009

Dear All, 
       I finally figured out the confusion over
Pteridophyta. If you look at the Catalogue of Life, it lists four
separate phyla Equisetophyta, Lycopodiophyta, Psilophyta, and
Pteridophyta (each having just one Class). Many of us still use the
single paraphyletic Phylum Pteridophyta that brings all four of those
Classes together.  A PhyloCoder might call this group the
"non-spermatophyte tracheophytes". 
       Apparently some strict cladist didn't like the
paraphyletic Pteridophyta, and therefore split it up into four separate
Phyla (Divisions), and then very confusingly attached the name
Pteridophyta to just the true ferns. No wonder there is so much
confusion, and why?----once again it's that strictly cladistic aversion
to any paraphyletic taxon whatsoever. Anyway, the Pteridophyta sensu
stricto is probably monophyletic (holophyletic), but the Pteridophyta
sensu lato is definitely paraphyletic. If the Catalogue of Life wants to
separate these groups into separate phyla (and then further obscure
their relationship by alphabetizing them), so be it. But they would at
least avoid most of the confusion if they used another name for
Pteridophyta sensu stricto (perhaps Filicophyta?). 
              --------Ken Kinman 
P.S. And I don't know why Peter Hovenkamp would think that my
classification system doesn't deal with monophyletic taxa. If you look
at any of my classifications, the vast majority of taxa are monophyletic
(i.e. holophyletic) clades, and then I occasionally put in paraphyletic
taxa where it is appropriate to maintain stability and add in that extra
anagenetic/divergence information (also referred to as mother-daughter
or ancestor-descendant information). My classifications are full of
clades, but I don't restrict myself to clades ONLY.   Just look at the
Diptera classification I posted this morning. Everything there is widely
considered to be a clade except for just 3 paraphyletic taxa:  (1)
Nematocera% (mother group of exgroup Brachycera), (2) Orthorrhapa%
(mother group of exgroup Cyclorrhapa), and (3) Empididae% (mother group
of exgroup Dolichopodidae). They are clearly labelled with the % symbol
for paraphyly. 

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