[Previous by date - short combined answer]
[Next by date - RE: RE: crown clade convention]
[Previous by subject - Re: RE: apomorphy-based names]
[Next by subject - Re: REPOST: Crowns, Panstems, and their Correspondence to ea=]
Date: Tue, 19 Oct 2004 18:13:17 -0400
From: [unknown]
To: phylocode@ouvaxa.cats.ohiou.edu
Subject: Re: RE: crown clade convention
A few responses to Jason's comments. My responses are in > <. The fact that Neotetrapoda hasn't been used isn't in my mind really s= trong evidence since Gauthier, Kluge and Rowe formally ignored it in Phylog= enetic=3D Nomenclature a mere 8 years after Gaffney suggested it, opting for th= e =3D crown convention because of problems seen with apomorphy-based definitions = (as argued by you and Jacques in 1990) that have subsequently been either corrected or shown false. Neotetrapoda has never received the weight = of authority that either the 1988 paper or the publication of the compan= ion volume would lend (which I see as a great opportunity to educate nonsystematists as to the importance in precision of name use). Still= , I =3D see your point. >The same is true for Neornithes, coined for the bird crown clade. = =3D Neontologists hardly ever use this name even when it is the appropria= te =3D one to use (e.g. "avain molecular systematics"). I'm not sure how on= e is =3D to judge "weight of authority", but I would think that in 1988 Gaffne= y, a =3D leading phylogeneticist, was viewed as carrying more authority than e= ither =3D Gauthier or Rowe, who were relative newcomers at the time. (Aside: = I =3D don't remember arguing that apomorphy-based definitions were problema= tic =3D in the 1990 paper. I've always been a supporter of all 3 of the orig= inally=3D proposed types of phylogenetic definitions.)< What is "best for biology" is for everybody to mean the same thing wh= en we use a name, thus either the crown or apomorphy definition is suboptim= al. =3D In the former case, there will be confusion engendered when "tetrapods" = are =3D no longer "Tetrapods", which will not only be among paleontologists but = also the educated general public who read Jenny Clack's or Carl Zimmer's r= ecent books, and among neontologists who still consider tetrapods to be lim= bed vertebrates even if some of their papers are less than precise. In th= e latter case, the confusion will continue to be as Michel and Kevin ha= ve characterized it, with inaccurate statements entering the literature = =3D (which I still think is a by product of an overly pedantic, literal reading = of =3D this literature). So the real question in my mind is how one determines wh= ich confusion is potentially greater, and I'm not so sure how that is don= e objectively. At this stage preference for either option seems to be b= ased =3D on opinion. >I don't see a big problem with calling them tetrapodomorphs, rather = than =3D tetrapods. In addition, I have to reiterate my earlier point that th= e =3D problem is not only the imprecise use of the well known names (which = Jason =3D attributes to an overly literal reading of the statements in question= --e.g.=3D , "tetrapods express gene y") but the fact that less well know names = =3D coined specifically for the crowns (e.g., Neotetrapoda) are consisten= tly =3D avoided by neontologists in precisely those situations when it would = be =3D appropriate to use them.< Regarding your number 2, respectfully, there has been an awful lot of= ink spilled over the clade of limbed vertebrates over the past ten years, including in the neontological literature. Obviously biologists have = a lot to say about this group (which they call "Tetrapoda"). >I didn't mean to imply that people didn't have much to say about the= =3D clade of limbed vertebrates--they clearly do. That's why we most = =3D definitely need a name for that clade. The point I was trying to mak= e is =3D that many more statements can be made about crown clades in terms of = =3D characters that are not commonly preserved in fossils (e.g., about ge= nes, =3D gene expression, physiology, behavior, etc.) and therefore it makes s= ense =3D to use the best known names for those clades. In fact, this is basic= ally =3D the reason that the widely known names are commonly used imprecisely.= =3D There are many statements that neontologists want to make (i.e., abou= t =3D rarely fossilized characters) that are justifiable only if interprete= d as =3D statements about the crown; however, neontologists also want to use t= he =3D widely known names. Therefore, they use the widelly known names AS I= F =3D those names refer to the crowns despite the fact that those names are= =3D supposed to refer to more inclusive clades and other less well known = names =3D are supposed to refer to the crowns. Because of the simple differenc= e in =3D numbers of neontologists versus paleontologists and the greater willi= ngness=3D that the latter group has shown to use the widely known names for th= e =3D crowns than the fomer group has shown to use the less widely known na= mes, =3D it seems that the most efficient way to achieve consistency is to ado= pt =3D the crown clade convention. Of course, this means that the paleontol= ogists=3D have to do the neontologists a favor. Basically, what we're asking = is =3D for Jason and other paleontologists to consider changing their otherw= ise =3D logical and traditional use of names to achieve greater overall consi= stency=3D of use. I realize that this is a big favor to ask, but I have a hig= h =3D opinion of paleontologists and think that there is a chance that they= may =3D ultimately be willing to do it.< Kevin 19 Oct 2004