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Vote on the Definition of "Aves"

As has been discussed many times on this list, the taxon "Aves" has
received several phylogenetic definitions over the years:

- "All descendants of the most recent common ancestor of Ratiti,
Tinami, and Neognathae." (Gauthier 1986:14)
- "The crown clade stemming from the most recent common ancestor of
Ratitae (Struthio camelus Linnaeus 1758), Tinamidae (Tetrao [Tinamus]
major Gmelin 1789), and Neognathae (Vultur gryphus Linnaeus 1758)."
(Gauthier and de Queiroz 2001:29)

- Ax 1987 (I don't have the exact wording, but it would be equivalent
to something like, "Extant birds and everything sharing more recent
ancestry with them than with any other extant organism." Under this
definition, dinosaurs would be a type of avian, not vice versa.)

- "Archaeopteryx, Passeriformes, and their common ancestor and all
descendants." (Sereno 1997:459)
- "Archaeopteryx plus extinct [sic: extant] birds and all descendants
of their most recent common ancestor." (Chiappe 1997:32)
- "Archaeopteryx, extant birds, and all descendants of their most
recent common ancestor." (Padian 1997:39)
- "The least inclusive clade containing Archaeopteryx lithographica
Meyer 1861 and Passer domesticus (Linnaeus 1758)." (Sereno 2005)

- Marjanovic 2006 (Published only in the ISPN Meeting abstracts. I
don't have the exact wording, but it was essentially, "[An extant bird
species] plus all organisms sharing more recent ancestry with it than
with [a list of about a dozen non-avians]." The list of non-avians
included things like dromaeosaurids, troodontids, and oviraptorosaurs
as well as some things usually considered more distants, such as
prolacertiforms and mammals, just to work under all phylogenetic
hypotheses. Thus, the definition does not necessarily include
Archaeopteryx, although it would under most phylogenies.)

- Actually, I don't know if this has been published, but I know there
are people who think it should be apomorphy-based.

Got a preference? Then vote! I've set up an informal poll here:
(So far "branch-based" is beating "crown group" by one vote.)
There is also a discussion below the poll.

Voting requires registering for the bulletin board:

Some other discussions that may be of interest to listmembers (e.g.,
"Definition of 'Dinosauria'") can be found here:
T. Michael Keesey
The Dinosauricon: http://dino.lm.com
Parry & Carney: http://parryandcarney.com