Message 2000-10-0022: Re: Moore's hybrid example (was Nathan Wilson's question)

Wed, 18 Oct 2000 08:05:23 -0400 (EDT)

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Date: Wed, 18 Oct 2000 08:05:23 -0400 (EDT)
From: Gerry Moore <gerrymoore40@hotmail.com>
To: velosa@cinenet.net, PhyloCode@ouvaxa.cats.ohiou.edu
Subject: Re: Moore's hybrid example (was Nathan Wilson's question)


Nathan drew:
>
>                4
>                /\      3
>               /  \     />              /    \   /  >             /      \ /    >            /        X      >           /        / \      >          /        /   \      >         /        /     \      >        /        /       \      >       /        /         \      >      /        /           \      >   7 / 12  9  / 10  5 13  6 \   1  \  2  8 11
>   \/   /  \ /   \  /  \  /  \  /   \ /  \  /
>    \  /    /     \/    \/    \/    A\    \/
>     \/    /      /     /      \      \   /
>      \   /      /     /        \      \ /
>       \ /      /     /          \      /
>       Y\      /     /            \    /
>         \    /     /              \  /
>          \  /     /                \/(Z)
>          B\/     /                 /
>            \    /                 /
>             \  /                 /
>              \/                 /
>               \                /
>                \              /
>                 \            /
>                  \          /
>                   \        /
>                    \      /
>                     \    /
>                      \  /
>                       \/Z
>


Nathan's example above represents one of the examples I have been working 
on.  Let's say Alpha is defined as the least inclusive clade containing 
species 3 and species 4.  If I am reading Nathan's cladogram correctly 
species 3 and 4 are each members of the clade Y and clade (Z) and the name 
Alpha could apply to either of these two clades based on its current 
definition.  The phrase "least inclusive" should not be used in choosing 
between nonnested clades even if one has fewer species than the other (since 
this may simply be a sampling artifact). Thus, I believe, the application of 
the name is ambiguous.  Following the other interpretation I presented the 
application of Alpha is not ambiguous as the name would be applied to clade 
Z. In other words, I agree with Nathan's analysis here.

However, based on the several examples I have been working, I am inclined to 
still go with Kevin's interpretation, with the understanding that 
conservations may be necessary in cases where it results in an undesirable 
circumscriptional change or where the application is ambiguous (as above). 
The issue gets more complicated (and I believe the other interpretation I 
presented fairs more poorly) when we expand the examples to include cases in 
which species of hybrid origin are used in not only node-based defintions 
but also stem-based defintions.

Cheers,

Gerry Moore
Brooklyn Botanic Garden
18 Oct. 2000
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