Message 2004-06-0046: Re: Pan-clades, good or bad?

Thu, 17 Jun 2004 00:20:43 +0200

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Date: Thu, 17 Jun 2004 00:20:43 +0200
From: David Marjanovic <>
To: PML <>
Subject: Re: Pan-clades, good or bad?

>   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.

They'd keep the same known content if Synapsida got an apomorphy-based
definition and Theropsida a stem-based one. (Until the much anticipated
discovery of a non-synapsid theropsid... I bet few people would call such an
animal a synapsid were it published tomorrow.)

> 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,

I've seen Anapsida pretty often -- almost every time turtles are not assumed
to be diapsids.

> which "euryapsids" or "anapsids" are NOT members of Diapsida,

No "anapsids" except turtles have ever been put into Diapsida, to the best
of my knowledge.

> the latter name has been applied as the most consitently and
> predominantly used opposing "stem" to Synapsida.

What, Diapsida?

> Theropsida and Sauropsida, though nice, also
> name apomorphic groups (does a turtle have
> the face of a lizard? or ichthyosaurs?)

I _really_ wouldn't consider "looks like a lizard" an apomorphy.

> 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.

Except that Diapsida is not used in the way you seem to imagine. For
example, see and

>   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 This compendium will NOT be published.

This is the abstract booklet.

>   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
> record.

This seems to be planned to happen at or after the Meeting...

>   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 is planned to happen.

> <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.

The latter cannot include the former. It can be a synonym, but that was it.

> Therapsida, to my knowledge, defines a non-pelycosaur grade
> which excludes, if I am not mistaken, dicynodonts and dinocephalians.

It includes both of the latter. Add mammals to this grade, and you get the
meanwhile common usage:

> <Have seemingly been emended to Varanopidae.>

I'm not defending any point of view here, just referring to the literature:

Jason S. Anderson & Robert R. Reisz: *Pyozia mesenensis*, a new, small
varanopid (Synapsida, Eupelycosauria) from Russia: "pelycosaur" diversity in
the Middle Permian, JVP 24(1), 173 -- 179 (25 March 2004)
        p. 173: "Throughout this study we follow the amended spelling of
Varanopidae (from Varanopseidae) of Reisz and Dilkes (2003)." Although
"2003", this paper is cited as being in press (Canadian Journal of Earth
Sciences). Weird, because this paper ?will? describe a new species that is
mentioned in this paper all the time.
        The e of Varanopseidae is not defensible even under the newest
edition of the ICZN. I imagine that this has made a difference.

>   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.

Then you can't say that it was used for the crown! This is like saying
Neornithes was used for more than the crown-group just because *Hesperornis*
and *Ichthyornis* were wrongly thought to belong to the crown-group in the
late 19th century.

> This does not change the "traditional" or "historical" use of the name.

...which reaches down all the way to *Adelobasileus*, several nodes away
from the crown.

> Gymnospermae will [...] likely be redefined as a
> conditional monophyly, as traditionally used.

Conditional monophyly? Hey, this reminds me of my abstract! :-)

>   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.

(Cladotheria and Theriiformes are parts of the crown-group.)

> <*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.

"Symmetrodonta" is a rhizome group. Some "symmetrodonts", like those you
mention, do lie outside the crown. Others lie inside.

> Notice that earlier in the cited message, I was using
> Mammalia as the _crown_. Thus, *Zhangheotherium.*

Which is inside.

> This clade is treated as within Trechnotheria,
> but not nominatively as a symmetrodont,

Because "Symmetrodonta" has been dropped by cladists, like "Thecodontia" and
"Eosuchia". Precladists, like the authors of *Maotherium* (thanks for the
ref), continue to call all those beasties "symmetrodonts".

> and certainly not a part of Spalac[o!]theroidea.

Really not?

> <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.

But it's ugly. :-)

> 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."

"Higher", as in "higher group", as in "higher rank", as in "containing". :-)
Or as in "more than" -- it contains more than just Primates.


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