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Date: Tue, 14 Sep 2004 14:47:14 -0700 (PDT)
From: [unknown]
To: Christopher Taylor <ck.taylor@auckland.ac.nz>
Cc: Mailing List - Dinosaur <dinosaur@usc.edu>, Mailing List - PhyloCode <phylocode@ouvaxa.cats.ohiou.edu>
Subject: Re: Panstems
--- Christopher Taylor <ck.taylor@auckland.ac.nz> wrote: > On 14/9/04 8:19 am, "T. Michael Keesey" <mightyodinn@yahoo.com> wro= te: > > http://dino.lm.com/keesey/documents/PhylogeneticNotation.doc >=20 > One point which I've noticed in the exemplar definitions, which= isn't a > problem with Mike's proposed notation, but a problem arising from o= ne of the > definitions -'Panaves'. My question is - how are we to properly def= ine crown > clades? Simply defining them as node clades doesn't seem sufficient= , as we > should allow for the possibility that some of the living members ma= y > eventually be moved phylogenetically outside the proposed node. > Mike defines Panaves as the panstem clade of the node Struthio = + Tetrao > + Vultur. Actually, de Queiroz and Gauthier did (in the Ostrom Symposium volume= ). It should also be pointed out that _Tetrao_ is not a specifier. _Tetr= ao major_ is the specifier, and it has been given its own genus since its origi= nal publication: _Tinamus_. I was merely citing the original form of the = species name. > Under the current popular phylogenies, this wouldn't really be a > problem - whichever the most basal branch of Aves is, most research= ers would > currently hold it to include one of these three. But among other ta= xa that > have been suggested in the past to be the most divergent living bir= ds are > Mesitornithidae, _Opisthocomus_ and _Todus_ (!). Conceivably, we co= uld get a > situation where these are not Aves. By some older molecular phyloge= nies, > Passeriformes would not even be Aves by the definition given. What = to do? You could use a stem-modified crown, e.g. "the first ancestor of all = currently extant organisms sharing more recent ancestry with _Vultur gryphus_ t= han with _Archaeopteryx lithographica_, plus all of that ancestors' descendant= s". That, or increase the number of internal specifiers. There has been some discussion about the general topic of crown and p= anstem clades on the PhyloCode Mailing List lately. Once again I urge everyo= ne interested in this topic to join. The instructions, once again, from http://phylocode.org: "If you would like to join an internet discussion group focusing on phylogenetic nomenclature, send a message to listserv@ohiou.edu. The = message should read: 'subscribe PhyloCode' (without the quotation marks). Do = not include anything else in the message. In a short time, you should rec= eive an automatic reply explaining how to send messages to the discussion gro= up." =3D=3D=3D=3D=3D =3D=3D=3D=3D=3D> T. Michael Keesey <http://dino.lm.com/contact> =3D=3D=3D=3D=3D> The Dinosauricon <http://dinosauricon.com> =3D=3D=3D=3D=3D> Instant Messenger <Ric Blayze> =3D=3D=3D=3D=3D =09=09 _______________________________ Do you Yahoo!? Declare Yourself - Register online to vote today! http://vote.yahoo.com