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Date: Sat, 11 Sep 2004 15:40:44 -0700
From: [unknown]
To: phylocode@ouvaxa.cats.ohiou.edu
Subject: Re: Panstems
Kevin de Queiroz wrote- > The problem with using standard affixes for ALL of the different cl= asses of names is that this practice > would result in the disruption of continuity for many, many names. = In the case of total clades, one could > argue that most names that have been associated with these clades h= ave also been associated with other > clades. Thus, the names could be defined as referring to the other clades, and the Pan- names could be > used for the total clades, without eliminating any widely known nam= es. For example, the name Synapsida > could be associated with the clade stemming from the species in whi= ch the synapsid apomorphy originated, > and PanMammalia could used for the t= otal group (which includes Synapsida) of Mammalia (used for the > crown). Thus, both preexisting names (Synapsida and Mammalia) are retained. However, if ALL of the > different types of clades are given names with standard affixes (e.= g., PanMammalia, ApoSynapsida, > ApoMammalia, AcroMammalia), then many preexisting names (e.g., Syna= psida, Mammalia) won't be used > for any clades, let alone for the clades to which they have traditi= onally referred. This disrupts > stability/continuity and thus goes against one of the fundamental principles of the PhyloCode. Pan-stems already disrupt continuity for many names, as most total cl= ades whose surrounding topologies are well known have been named already. Here are some total clade names that come to mind- Amphibia =3D Panlissamphibia. Salientia =3D Pananura. Urodela =3D Pancaudata. Reptiliomorpha =3D Panamniota. Synapsida =3D Panmammalia. Metatheria =3D Panmarsupalia. Eutheria =3D Panplacentalia. Sauropsida =3D Panreptilia. Anapsida =3D Pantestudines. Romeriida =3D Pansauria. Lepidosauromorpha =3D Panlepidosauria. Archosauromorpha =3D Panarchosauria. Avemetatarsalia =3D Panaves. Many of these names are very commonly used. Changing them all would = be quite disruptive. In addition, basically every 'family' or 'order'-level clade with liv= ing representatives is understood to include some taxa basal to the crown version of that clade. So taxa directly basal to crown galliformes a= re placed in Galliformes too (e.g. Paraortygoides in Dyke and Van Tuinen= , 2004). Yet you would have us redefine Galliformes to be a crown clad= e, and make Paraortygoides a non-galliform pangalliform. It's the same with Diacodexis and Artiodactyla, Basilosaurus and Cetacea, etc.. Have existing total clade names been associated with more alternate definitions than other kinds of clade names? I don't think so. The = most controversial clade names (Aves, Tetrapoda, Mammalia) are either crow= n or non-crown node-based clades. If you really want to introduce a stand= ardized affix, crown clades have the least names associated with them. But I= agree with Jaime that recommending affixes for only one type of definition = is nonsensical. Perhaps a better recommendation would be to keep existi= ng names the same, but if you want to name a crown or total clade equiva= lent to an existing clade, use the pan- or acro- affixes. This would cut dow= n on memorizing new clade names AND avoid disruptive renaming. Mickey Mortimer Undergraduate, Earth and Space Sciences University of Washington The Theropod Database - http://students.washington.edu/eoraptor/Home.= html