Message 2004-06-0040: Re: Pan-clades, good or bad?

Wed, 16 Jun 2004 13:58:54 -0700 (PDT)

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Date: Wed, 16 Jun 2004 13:58:54 -0700 (PDT)
From: "Jaime A. Headden" <>
Subject: Re: Pan-clades, good or bad?

David Marjanovic ( wrote:
<How do you mean, "unlikely"? Theropsida was specifically invented in 1930
for what would today be called the node-stem triplet
*Amniota*-*Theropsida*-*Sauropsida*. It is the one logical candidate for
the name of "*Panmammalia*" and even has some limited use in at least the
secondary, tertiary and popular literature.>

  Synapsida is used more widely and dominantly for the same content.
Theropsida (not Therapsida) is less used by degrees. I do think that it
should NOT be defined to be a "panstem" in the sense, since Synapsida
already has the historical placement here, even if that was not the
intention. Though Synapsida was coined under the basis of an apomorphic
grouping on the lines of Anapsida, Euryapsida, and Diapsida, the use of
the first two is in disfavor, and only with possible fluctuating
phylogenies about which "euryapsids" or "anapsids" are NOT members of
Diapsida, the latter name has been applied as the most consitently and
predominantly used opposing "stem" to Synapsida. Theropsida and
Sauropsida, though nice, also name apomorphic groups (does a turtle have
the face of a lizard? or ichthyosaurs?) whereas "beast faces" will be
forced to include a mental image of "pelycosaurs" which have NO cranial
features that one would relate to being "mammalian" (use of _thero-_ being
a reference to mammals explicitly, back when "pelycosaurs" were considered
a different group altogether). Now, while I agree that Diapsida should be
a apomorphy-based clade, given that origin of the diapsids, as in the
synapsids, was from a "euryapsid" or "anapsid" ancestor, the idea that
these names NOW refer to the stem-names under amniotes should be retained,
if at all possible.

<If you read the entire abstract volume, you have found that Amphibia is
defined there twice in two different ways.>

  Among countless other names.

  Naw. This is how I would like to see the definitions published:

  1) proposals for definitions are _gathered_ into a single compendium.
This compendium will NOT be published.

  2) groups of experts (who agree with the Code anyway) and the literature
will be used to gague which of these definitions will be considered _the_
definition for that given name. It's put up to VOTE and in the case of a
tie, another expert not chosen or the literature will be chosen to select
a definition that will have the LEAST obtrusive impact on the historical

  3) thus, the name is selected. This name then goes to the
pre-publication compendium of "chosen" names. The volume, when completed,
will be published alongside the Code.

  This means MY name will not gain precedence via definition over anyone
else's, because I was not as thourough with the literature as I should
have been. Or because I was biased. Or chose not to follow the articles
and recommendations (some of the latter should be rules, frankly).
<You have confused Theropsida and Therapsida. Theropsida contains (or is
synonymous with) Synapsida, and both contain Therapsida.>

  I did not confuse Theropsida with Therapsida. Use of the names
Theropsida and Synapsida together have, to my knowledge, been extremely
limited but when done, the latter was in precedence or more inclusion to
the former. Therapsida, to my knowledge, defines a non-pelycosaur grade
which excludes, if I am not mistaken, dicynodonts and dinocephalians.

<Have seemingly been emended to Varanopidae.>

  Shouldn't be. The nomenclature should be stabilized to first use,
flinging idealism about stems being "fixed" _after_ publication. I sure
don't see Manuraptora or Ceratopidae being used regularly.

<Pardon? Traditionally it's used for a bigger group. The idea of
restricting it to the crown-group comes from 1988 and has only very
recently caught on.>

  The longest running traditional use for Mammalia was applied as a crown.
Other forms were "mammal-like" in one way or another or considered steming
from the ansector of the crown itself as in early 1900's literature. Only
recently has this changed. This does not change the "traditional" or
"historical" use of the name. This is the main reason why proponents of
the crowns prefer using Mammalia for that clade, not another name. I would
agree that Mammalia and Aves should be crown names. Neornithes should be
used as a stem. Gymnospermae will also likely be redefined as a
conditional monophyly, as traditionally used.

  Because of this possibly more ideally restricted use of Mammalia,
Holotheria has a utility, as does Mammaliaformes, Cladotheria,
Theriiformes, etc., beyond just naming every possible node or stem from
the crown to non-mammaliaform cynodonts.

<*Zhangheotherium* (named after a certain Zhang He) is far inside. It's a
spalacotheriid ( = Real True Symmetrodont).>

  Symmetrodonta, like *Kuehneotherium* and *Hadrocodium* lie OUTSIDE the
crown group. Notice that earlier in the cited message, I was using
Mammalia as the _crown_. Thus, *Zhangheotherium.* Recently, with the
description of a new holothere, there is now a Zhangheotheridae [sic]
including *Z. quinquecuspidens* and *Maotherium sinensis.* This clade is
treated as within Trechnotheria, but not nominatively as a symmetrodont,
and certainly not a part of Spalacatheroidea.
<If, then rather Neo-.>

  Naw, "Corono-" brings immediately the use of "Crown-" prior to the idea
of a "new"[blank] name. Neo has no other use than to indicate, as
previously indicated, a "smaller" subset that is not typically homologous
in content to the contained clade name being highjacked.

<This is why I prefer the name Supraprimates instead of Euarchontoglires,
coined (but _likewise_ not defined) in>

  Euarchontaglires gives us the idea it includes Euarchonta + Glires.
Supraprimates has two intuitive feelings to it: it names a clade of
animals that are "more than" primates, or that it names a group of animals
_like_ primates, but aren't. _Supra-_ has a condition of "higher than" and
not "containing."


Jaime A. Headden

  Little steps are often the hardest to take.  We are too used to making leaps in the face of adversity, that a simple skip is so hard to do.  We should all learn to walk soft, walk small, see the world around us rather than zoom by it.

"Innocent, unbiased observation is a myth." --- P.B. Medawar (1969)

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