Message 2004-10-0023: Re: Panstems

Sat, 11 Sep 2004 15:40:44 -0700

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Date: Sat, 11 Sep 2004 15:40:44 -0700
From: [unknown]
Subject: Re: Panstems

Kevin de Queiroz wrote-

> The problem with using standard affixes for ALL of the different cl=
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=
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=
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=
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.=
PanMammalia, ApoSynapsida,
> ApoMammalia, AcroMammalia), then many preexisting names (e.g., Syna=
Mammalia) won't be used
> for any clades, let alone for the clades to which they have traditi=
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=
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 =
quite disruptive.

In addition, basically every 'family' or 'order'-level clade with liv=
representatives is understood to include some taxa basal to the crown
version of that clade.  So taxa directly basal to crown galliformes a=
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 =
controversial clade names (Aves, Tetrapoda, Mammalia) are either crow=
n or
non-crown node-based clades.  If you really want to introduce a stand=
affix, crown clades have the least names associated with them.  But I=
with Jaime that recommending affixes for only one type of definition =
nonsensical.  Perhaps a better recommendation would be to keep existi=
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 -


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