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

[Stanley Friesen <sarima@ix.netcom.com>]

At 11:47 AM 7/13/99 -0400, T. Mike Keesey wrote:
>The problem with the traditional system is that once you recognize one
>paraphyletic group, it rules out many others from ever being recognized --
>others, which, by your criteria, are just as real. For example, if we
>define Reptilia as (Amniota - Mammalia) - Aves, then we are incapable of
>naming Amniota - Mammalia, or (Tetrapoda - Mammalia) - Aves, or any other
>number a paraphyletic groups.

Yes, this is strictly true.  But, just as cladistic taxonomists choose to
name only a subset of the clades in a cladogram, so in a hybrid system the
taxonomist chooses which paraphyletic groups are sufficiently interesting
to name.  The main criterion is utility.  The taxa which have the highest
biological information content are the ones that are most worthy of
recognition.

You might want to look at my discussion of this issue in:
http://www.crl.com/~sarima/dinosaurs/philosophy/infocontent.html
and
http://www.crl.com/~sarima/dinosaurs/philosophy/linnaean.html

>mean "non-avian dinosaur". Yet I find that a lot of times when I go to say
>"non-avian dinosaur", I really mean something else -- "non-neornithean
>dinosaur", "non-avialan dinosaur", "non-paravian dinosaur",
>"non-maniraptoran dinosaur", etc.

Well, as I would use the name Aves for what you call Avialae, I would use
that definition anyhow.

--------------
May the peace of God be with you.         sarima@ix.netcom.com