Message 2001-02-0033: RE: apomorphy-based names

Wed, 07 Feb 2001 16:47:45 -0600 (CST)

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Date: Wed, 07 Feb 2001 16:47:45 -0600 (CST)
From: "Jonathan R. Wagner" <znc14@TTACS.TTU.EDU>
To: "Moore, Gerry" <>
Cc:, Dequeiroz.Kevin@NMNH.SI.EDU
Subject: RE: apomorphy-based names

At 02:34 PM 2/6/01 -0500, you wrote:
>  I believe the intent (Jonathan W. or Kevin deQ. please correct me if am
>wrong) of this draft recommendation is to deal with former suprafamilial
>names developed in the traditional system in which the name is not based on
>a type genus (e.g., Magnoliaceae based on the type genus Magnolia) but
>rather is based on a character (e.g., Monocotyledonae).

        Exactly! It seemed consistant, in that if we insist that type taxa
be internal specifiers, we should at least ask for definitions that
explicitly specify an apomorphy for clade named for that apomorphy. Ask, not
insist, in this case.

>However, the way
>Recommendation 11.8C is written it would suggest that  _all_ names "derived
>from apomorphy names be given apomorphy-based defintions".

        Please see my response to Dr. De Quieroz (sorry, this is something
of bad form, but I have been trying very hard to catch up on a bundle of
e-mail, so I handled the short messages first).

>Thus it seems to
>cover former generic names that are derived from an apomorphy name.
        As I have recently posted, I think we need to be very careful with

>In these cases,
>doesn't Recommendation 11.8C indicate that the apomorphy definition is to be
>given preference over stem- and node-based definitions?   

        No. It would recommend to the namer that they be used. Am I just
misinterpreting the meaning of the term "recommendation?"

        On another hand, I was not even considering genus names, as I was
under the mistaken impression these were off limits until we decided what to
do with species (since some of the Cantino et al. options preclude the use
of at least some genus names as clade names).

>  D. Hillis's example using the genus name Gastrotheca shows how there can
>be translation and derivation determination difficulties. Should the name be
>literally translated as "stomach pouch" and thus not having to do with the
>pouch on the back or can it be more loosely translated so as to be derived
>from the character involving the pouch on the backs of the females?  

        Again, the systematist might invoke good judgement, and the fact
that Recommendation 11.8C is just that, a recommendation, and use a node- or
stem-based definition, or a different apomorphy-based definition (despite
Recommendation 11.8E.

        Must/should we spell out "but you don't have to," at the end of each
of these recommendations. Or put the universal catch-all about failure to do
so not being grounds for rejection of a name?

>  Also regarding new names let's say someone has identified a clade and
>provided it with a stem- or node-based definition. Recommendation 11.8C
>seems to frown on one then coming up with a new name for this clade that is
>derived from an apomorphy name.
        OK, please forgive what may seem like pedantry, but what you wrote
is not clicking with me:
        A clade is a clade, there is no defining a clade... you define a
name. If I find a clade in my analysis, and "provide it with a definition,"
I must also be providing it with a name. A new name, then, must perforce
involve a new definition, because if it had the same definition, it would
sink in objective synonymy. Althought the Code doesn't "frown" on this, it
is pretty much pointless. With a new definition, the two names are NEVER
objectively equivalent, uness the definitions are equivalent (as above). If
they describe the same clade in your phylogeny, your new name would be sunk
in synonymy (so why are you naming it?). Long story short, I'm afraid I
don't see your point.
        If you are implying that the 11.8C "frowns" on using an
apomorphy-based name for a node- or stem-based definition, this is exactly
what it does. I hardly think the scorn of a mere Recommendation will keep
systematists from doing this, however.

>Thus, one has less freedom in how to develop
>a name for a clade when following Rec. 11.8C. and using stem- and node-based

        Not really, because you can ignore it if you feel it is necessary,
on a case-by-case basis. The examples included were meant to show different
situations, and give a feel for the type of issues involved. I don't think
most serious practitioners want to see an apomorphy-based Tetrapoda or
Mammalia, but some less important, less well known clades, which are very
strongly indicated by a very pronounced apomorphy (like Ankylopollexia)
might warrent the application of such a definition. This is a recommendation
intended to make the namers or converters of such taxa think twice before
automatically applying a node- or stem-based definition.

        Dr. De Quieroz take note: Many converters seem to tend towards the
latter option (above), looking at recent cladograms and opting for a
defintion which encompasses the CONTENT of the traditional group. This is
especially evident in Paul Sereno's recent definitions based on his
ornithischian phylogeny, and is indicative of one approach to the use of PN
(as a tree descriptor, rather than a nomenclature for biological entities).

>It probably poses less problems when converting
>suprafamilial names that are based on apomorphy names  and that have well
>established apomorphy-based concepts.   

        Then perhaps these are the cases which it will serve best. Indeed,
these are the cases for which it was intended. Which is why it was proposed
as a recommendation, not a rule.

        Again, I hope this does not seem curt. I am trying to give Dr.
Moore's thoughts their due, while managing a tight schedule. Dr. Moore, no
offense is meant in any way.

     Jonathan R. Wagner, Dept. of Geosciences, TTU, Lubbock, TX 79409-1053
  "Why do I sense we've picked up another pathetic lifeform?" - Obi-Wan Kenobi


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