Message 2001-02-0001: Addendum 1: Clade names from apomorphy names

Mon, 05 Feb 2001 14:45:03 -0600 (CST)

[Previous by date - New(?) Paper]
[Next by date - Addendum 2: Nominal apomorphy as specifier]
[Previous by subject - Accidentally deleted e-mails...]
[Next by subject - Addendum 1b: Clade names from apomorphy names]

Date: Mon, 05 Feb 2001 14:45:03 -0600 (CST)
From: "Jonathan R. Wagner" <znc14@TTACS.TTU.EDU>
Subject: Addendum 1: Clade names from apomorphy names


        In reviewing the literature for an upcoming paper, the issue of the
names of apomorphy-based clades, and the definitions of clades named after
apomorphies came up. Not that I believe there is any need for strict rules
on this subject, but I felt that the following three recommendations might
be appropriate. Note that I have sent them separately, although they should
probably be considered as part of the same discussion.

        Jonathan R. Wagner


Draft item (Recommendation 11.8C?) for PhyloCode, Article 11

Recommendation 11.8C: It is suggested that clade names derived from
apomorphy names be given apomorphy-based definitions, although it is
recognized that this may not always be practical. More traditional,
established names often take on a life of their own, and have limits that
the apomorphy-based definition would not capture effectively.

	Example 1: _Arctometatarsalia_ Holtz 1994 was redefined by the original
author (Holtz 1996) because of perceived problems with apomorphy-based
definitions. However, given that the original "concept" of the taxon was
centered on the apomorphic configuration of the pes, it might be more
appropriate to retain the original definition.

	Example 2: It could be argued, on the above grounds, that _Mammalia_ might
be best defined using the specifier "mammary glands." However, because of
the rarity of soft-tissue preservation in fossils, most definitions/
diagnoses of the clade, at least in the context of the evolution of the
group, have centered on osteological characters. Recent attempts to impose
"crown-clade," other node-based and osteological apomorphy-based definitions
serve to illustrate that a mammary-gland specified definition is probably
not useful to the systematic community.

     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


Feedback to <> is welcome!