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Taxonomic levels in birds



I think that there is a practical issue that debates on what birds "are" on
this list have ignored.  This is the effect of trying to force an
evolutionary tree, however derived, into the LInnaean system (or vice
versa).  Doing so creates  a practical problem that will differ depending on
your specialty.

Ornithologists divide living birds into some 20-30 orders and over 100
families.  This system is highly convenient for bird students.  But if birds
are merely a subset of maniraptorian dinosaurs, what happens to all those
orders and families?  Ideally they should be reduced to lower categories -
but unless you are going to call each family a genus or at best a tribe,
that means using all sorts of intermediate terms beginning with sub-,
inter-, infra-, etc etc. and I don't think ornithologists are ready to do that.

But it gets worse.  According to the classification in Long's "The Rise of
Fishes" all tetrapods belong in the Division Tetrapoda of the Subclass
Crossopterygii in the Class Osteichthyes!  By this classification (though he
doesn't carry it through for us to see as his book is about "real" fishes) I
imagine all Archosaurs constitute at best an order, with Ornithischia and
Saurischia reduced to, perhaps, family level and all living birds, all 9000+
species of them with all 20+ orders etc, reduced to, perhaps, a single tribe
in the subfamily that includes all carnivourous dinosaurs!

In short, inconsistencies are almost forced upon us if the whole system is
not to get so unwieldy as to be of no practical use. I have no solution for
this, but it might shed some light on why some ornithologists are unhappy
about saying birds "are" dinosaurs even though that is cladistically
correct.  I don't hear people here arguing that all dinosaurs are
crossopterygian fishes, but the  argument is identical.
--
Ronald I. Orenstein                           Phone: (905) 820-7886 (home)
International Wildlife Coalition              Fax/Modem: (905) 569-0116 (home)
Home: 1825 Shady Creek Court                  Messages: (416) 368-4661
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Toronto, Ontario Canada M5H 3P5