Message 2004-06-0023: RE: First International Phylogenetic Nomenclature Meeting

Tue, 15 Jun 2004 21:27:20 -0700 (PDT)

[Previous by date - Re: First International Phylogenetic Nomenclature Meeting]
[Next by date - Re: Pan-clades, good or bad?]
[Previous by subject - RE: Fetching Email Archives]
[Next by subject - RE: Genus names]

Date: Tue, 15 Jun 2004 21:27:20 -0700 (PDT)
From: "Jaime A. Headden" <>
Subject: RE: First International Phylogenetic Nomenclature Meeting

Tim Williams ( wrote:
<_Megalosaurus bucklandii_ might be a nomen dubium.  Rauhut seems to think
so.  It's probably a bad idea using nomina dubia as specifiers, so I can
see why _M. bucklandii_ might have been shoved aside.>

  Both *M. bucklandii* and *C. montanus* are admittedly dubious names,
with limited application to diagnosing taxa. They are distinct largely
historically. However, to use *Megalosaurus* as was done follows:

  Article 11, Recommendation 11A: "Definitions of converted clade names
should be stated in a way that attempts to capture the spirit of
historical use to the degree that it is consistent with the contemporary
concept of monophyly. Consequently, they should not necessitate, though
they may allow, the inclusion of subtaxa that were historically excluded
from the taxon. To accomplish this goal, internal specifiers of converted
clade names should be chosen from among the set of taxa that were
considered to form part of a taxon under either the original or
traditional ideas about the composition of that taxon, and they should not
include members of subtaxa that were not historically considered part of
the taxon."

  Example 1: "The name Dinosauria was coined by Owen for the taxa
*Megalosaurus,* *Iguanodon,* and *Hylaeosaurus,* and traditionally the
taxon designated by that name has included these and certain other
non-volant reptiles. It has not traditionally included birds. Although
birds are now considered part of the dinosaur clade, the name Dinosauria
should not be defined using any bird species as internal specifiers. Such
a definition would force birds to be dinosaurs, thus trivializing the
question of whether birds are dinosaurs. Instead, internal specifiers
should be chosen from among taxa that have traditionally been considered
dinosaurs; e.g., *Megalosaurus bucklandi* von Meyer 1832, *Iguanodon
bernissartensis* Boulenger in Beneden 1881, and *Hylaeosaurus armatus*
Mantell 1833."

  One should note that while the actual holotype species of *Iguanodon* is
*I. anglicus,* the NEOtype is *I. bernissartensis.* Thus, Owen's original
inclusion is NOT "*Iguanodon bernissartensis* Boulenger in Beneden 1881,"
but rather, it is "*Iguanodon anglicum* [sic] Holl, 1829."

  In order to preserve consistency with the historical record, the
original nomenclature is prefered. Jon Wagner (speaking for ya bud) is
aware of this and I think considers it the lesser of two evils.

<.... _Ceratops montanus_ is probably a nomen dubium.>

  Given that *Ceratops montanus* is THE nominative taxon for Ceratopsia,
it could be unwise to use another internal specifier. 

  Phylocode, Article 11.8: "In the interest of consistency with the
preexisting codes, it would be desirable for a clade whose name is
converted from a genus name under a preexisting code, or is derived from
the stem of a genus name, to include the type of the genus name.
Therefore, when a clade name is converted from a preexisting genus name or
is a new or converted name derived from the stem of a genus name, the
definition of the clade name must use the type species of that genus name
at the time of establishment as an internal specifier."


  Article 9, Recommendation 9B: "Establishment of names for poorly
supported clades should be done with careful consideration of possible
nomenclatural consequences if the phylogenetic hypothesis turns out to be
incorrect. It may frequently be advisable to use only informal names for
poorly supported clades."

  To use *Triceratops,* the next oldest available taxon that is considered
valud, one could just name a new clade Triceratopsia, or define the clade
as an apomorphy-based taxon, for find exception. On the other hand, some
HAVE suggested *Ceratops* may be valid ... I think Dodson suggested
*Avaceratops* and *Ceratops* may be synonyms or sister-taxa. I forget.


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)

Do you Yahoo!?
Yahoo! Mail is new and improved - Check it out!


Feedback to <> is welcome!