Re: Dino Birds (was Re: Dinosaur = extinct animal)

["T. Mike Keesey" <tkeese1@gl.umbc.edu>]

On Mon, 19 Jul 1999 Dinogeorge@aol.com wrote:

> In a message dated 7/19/99 10:13:03 AM EST, tkeese1@gl.umbc.edu writes:
> 
> << But naming a traditional paraphyletic taxon can exclude other taxa (para-
>  or monophyletic) from ever being recognized, whereas naming a phylogenetic
>  taxon never precludes the possibility of naming other clades. No
>  possibilities are ruled out.  >>
> 
> Don't see how naming a paraphyletic taxon rules out naming other taxa. Can 
> always discard paraphyletic taxon when it proves less useful than 
> naming/using another set of taxa.

See? You're still sacrificing one for the other, when, objectively, each
is just as useful as the other.

PT is an equal opportunity classification system. Every recognized clade
can be referred to by one word. Every recognized singly paraphyletic group
can be referred to by two words ("non-A B's"). Every recognized doubly
paraphyletic group can be referred to by three words ("non-A, non-B C's").
It can continue beyond that, but at some point, it becomes easier to say
"basal"  -- a somewhat arbitrary term, but no more arbitrary than formally
recognizing a taxon for such a group. 

No constant, arbitrary revisions necessary.

--T. Michael Keesey
tkeese1@gl.umbc.edu | THE DINOSAURICON: http://dinosaur.umbc.edu/
AOL IM:   RicBlayze | WORLDS:    http://www.gl.umbc.edu/~tkeese1/