Message 2001-02-0022: Re: apomorphy-based names

Tue, 06 Feb 2001 15:19:23 -0500

[Previous by date - Genus names]
[Next by date - RE: Genus names]
[Previous by subject - Re: apomorphy-based names]
[Next by subject - Re: apomorphy-based names]

Date: Tue, 06 Feb 2001 15:19:23 -0500
From: david baum <>
Subject: Re: apomorphy-based names

Kevin de Queiroz said:

>When one examines the way in which certain names are used, it becomes very
>clear that some people have an apomorphy-based concept of the clade to
>which they are referring.

It is true that we sometime conceptualize clades based on apomorphies. For
example, like most botanists I think of Angiospermae as being "defined" by
the enclosure of ovules/seeds in carpels.  (Perhaps this reflects some kind
of essentialistic core in us all that drives us to insert evidence
[characters] as proxies for things [clades] whose existence we cannot
directly observe.)  However, I think that when we get to the point of
naming a clade within the framework of the PhyloCode (or converting a
preexisting name) we should be required to go beyond a "primitive,"
character-based understanding and say something about historical
relationships.  Thus, I think the name, "Angiospermae"  should be attached
to a specific genealogically specified clade:  E.g.,"The most inclusive
clade including Arabidopsis thaliana but not Gingko biloba, Pinus
sylvestris, Welwitschia mirabilis......" or " the least inclusive clade
including Amborella trichopoda, Nyphaea, etc......).

Similarly, just because hair, mammary glands, a dentary-squamosal joint or
whatever (!) have been taken to "define" (I prefer "diagnose") a clade
named Mammalia does not, in my mind, negate the responsibility to attach
the name to one unambiguously indicated clade.  And the least ambiguous way
to attach names to clade is using specifiers (and even then we are assuming
a strictly divergent tree [but that's another topic!]).

Jonathan Wagner said:

>Without wishing to seem insulted, I feel I shold interject. I
understand the frustration that Dr. Baum seems to feel regarding the
differing approaches to nomenclature necessitated by our respective
disciplines (see Dr. De Quieroz's points). I certainly don't want to imply
that I think Dr. Baum is being deliberately coarse, sometimes I too feel
his frustration too. However, I feel I must defend the practitioners of PT
in vertbrate paleontology.

I admit it was coarse and unfair to stereotype VP's in this way!  As you
note some frustration slipped-out.  Negative comments about
over-philosophical botanists are warranted in response!

Jonathan also said:

>VP workers may be more inclined toward apomoprhy-baed definitions, I do
>not feel that we project a *need* for them.

In that case where is this projection coming from?   Maybe we are all
disinclined towards apomorphy-based definitions but are politely assuming
that somebody else wants them.  So, who does?  Based on the recent emails
is this a fair summary?

Pro: Kevin
Anti: David H, David B.
Open to allowing them but not inclined to use them: Jonathan, David M.(?)


David Baum
Dept. Organismic and Evolutionary Biology
Harvard University Herbaria
22 Divinity Avenue
Cambridge MA 02138

Tel: (617)496-6744, -8766
Fax: (617)495-9484


Feedback to <> is welcome!