Re: phylo tax

[jrhutch@socrates.berkeley.edu (John R. Hutchinson)]

As I do try to avoid lengthy discussions on cladistics on the list (but
often can't help it), this will be my last posting on this subject.


Darren Naish writes:

>John R. Hutchinson writes:
>> >There does not need to be conflict between Aves and Avialae IMHO;
>>         Check.
>> >Chiappe and others have recently [...] explicitly defined Aves as the most
>> >recent common ancestor of the Neornithes [...] and Archaeopteryx, and all
>> >descendants of that MRCA.
>        Which might or might not be synonymous with Avialae. The point
>however being that Aves *has* been defined in PT, and it was defined as a
>crown group, and if we are ever going to get anything done, we need to have
>rules. We all hate 'em, but we gotta have 'em.

Avialae is a stem-based taxon; Aves is node-based. They can't be
synonymous, just like Pseudosuchia and Crurotarsi can't (please don't open
that can of worms further  :-) ).

As far as crown groups and priority go... well, I'll leave that to Chiappe,
Norell, Gauthier, Novas, and the other experts that are working on the
systematics of Aves. I will express my opinion that I like Chiappe's
definition much better than the crown group version, but again I will defer
to the experts and let them slug it out.


Dinogeorge and Darren Naish say:

>> >I'm rewriting MM #2 third edition to refer to existing phylogenetic
>> >definitions of dinosaur taxa and to provide such definitions for taxa that
>> >don't already have them, with due regard for nomenclatural priority, of
>> >course.
>        Oh dear lord. Please, George, before you do this, can we have a
>little talk? If you're going to be publishing taxon definitions that someone
>might have to accept, there are a few things I'd like to say.

No need for any concern; there are already papers submitted/in press that
are taking care of this issue. The upcoming _Encyclopedia of Dinosaurs_ has
an emphasis on phylogenetic definitions (trust me; I've read quite a bit of
it... and even wrote some [go ahead and cringe; I'm cringing too]). As far
as primary literature goes, there's other stuff in the works already.

OK, back to the homologies of the diapsid flexor tibialis internus...

                       --John R. Hutchinson