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Re: PRIORITY RULES



>John R. Hutchinson wrote:
>
>> There does not need to be conflict between Aves and Avialae IMHO; Avialae
>> (sensu Gauthier) is a stem-based taxon, while Aves (as most workers would
>> use it) is node-based. Chiappe and others have recently (e.g the Mononykus
>> paper in the Gondwanan dinos volume, and other recent papers by Chiappe)
>> explicitly defined Aves as the most recent common ancestor of the
>> Neornithes (as used by many ornithologists for the crown group birds) and
>> Archaeopteryx, and all descendants of that MRCA.
>>
>> This does conflict with Gauthier's use of Avialae as the sister taxon for
>> Deinonychosauria, as Novas and others have stuck with.
>
>I had no idea the two clades were different. Does this mean that creatures
>like Unenlagia and Protarchaeopteryx might be non-avian avialines?

I think it's a bit early to say for sure; Protarchaeopteryx has yet to be
incorporated into a comprehensive phylogenetic analysis, and I haven't seen
Unenlagia in person or done a cladistic analysis of its phylogenetic
affinities, so I'd have to defer to the authors who have.

However, I'd speculate, unofficially, and with an air of extreme caution,
that the answer would be "yes;" at least Unenlagia is a member of the
stem-based clade Avialae, but lies outside Aves. I don't know about
Protarchaeopteryx or any other candidates waiting in the wings (pun
intended; sorry).

Novas and Puerta's cladogram shows Unenlagia as the sister taxon to Avialae
within "unnamed node," but this does not follow the spirit of Gauthier's
formulation of Avialae as the sister taxon to
Deinonychosauria/Dromaeosauridae. Officially, I'd prefer to respectfully
defer to the authors, though. They wrote the paper, not me -- I'm just
expressing an informal opinion. I think the issue will be clarified by
upcoming papers on maniraptoriform phylogeny.

                       --John R. Hutchinson