Message 2000-10-0006: Fwd: RE: Nathan Wilson's question

Tue, 10 Oct 2000 11:28:01 -0400

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Date: Tue, 10 Oct 2000 11:28:01 -0400
From: Philip Cantino <cantino@ohiou.edu>
To: PhyloCode@ouvaxa.cats.ohiou.edu
Subject: Fwd: RE: Nathan Wilson's question

It is rather late to re-enter this discussion, but other 
responsibilities prevented me from keeping up with it last week and I 
didn't get a chance until now to wade through the various 
contributions.  I am confused by Gerry Moore's position, as presented 
in his first message on this subject and referred to subsequently.

GM:
>   I actually see the issue that Nathan Wilson brought up as potentially
>being problematic, since a species that may eventually be shown to belong to
>multiple nonnested clades may be used in phylogenetic definitions (as a
>specifier) _prior_ to the knowledge that the species actually belonged to
>more than one nonnested clade.
>   For example, let's say Clade Z is defined as the least inclusive clade
>containing species 3 and species 4. Species 3 is then shown to have
>originated through the hybridization between species in Clade A and Clade B.
>When the definition was originally formulated it was believed that species 3
>was a member of only Clade A (not B) and the circumscription of Clade Z was
>exclusive of Clade B.  Doesn't the circumscription of Clade Z have to
>include all nonnested clades to which each specifier (see Art. 11.1) is a
>member (i.e.,  the circumscription of Clade Z will have to be expanded to
>include Clade B to accommodate specifier Species 3 being a member of the
>nonnested Clades A and B)?


I don't understand why Gerry thinks that the circumscription of Clade 
Z must include all nonnested clades to which each specifier belongs. 
He refers to Art. 11.1, perhaps meaning the last sentence of this 
article: "If subordinate clades are cited in a phylogenetic 
definition of a more inclusive clade, their specifiers must also be 
explicitly cited within the definition of the more inclusive clade." 
However, this sentence just says that if you want to cite a 
subordinate clade (rather than a species or specimen) as a specifier, 
you must go on and state the specifiers of the subordinate clade.  It 
says nothing about the named clade containing all clades to which 
each specifier belongs.  Clearly, the named clade can't include all 
nested clades to which each specifier belongs (if it did, every name 
would refer to the clade comprising all of life).  Why should it 
include all non-nested clades to which each specifier belongs?

Phil



Philip D. Cantino
Professor and Chair
Department of Environmental and Plant Biology
Ohio University
Athens, OH 45701-2979
U.S.A.

Phone: (740) 593-1128; 593-1126
Fax: (740) 593-1130
e-mail: cantino@ohio.edu

  

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