Question(s) about Cladistics and PhyloCode

[Jeff Leach <leachjeff2@hotmail.com>]

This isn't really the proper list for these question, so if anyone knows of 
some relevant articles or list(s) can you point me in the right direction.

1. If I understand correctly under PhyloCode clade definitions don't change 
(A node can move around on a tree but its definition is always the same). My 
question is - are not clade definitions based only on extinct taxa in a 
state of flux?

As an example: a paper defines a taxon as a finite number of character 
states, a cladistic analysis is done and a tree is printed in an article. So 
we have a tree were every node is clearly defined. Now a few years later a 
new article is published and it adds a few character states to the previous 
list, a new analysis done, and the new tree is nearly identical to the 
previous one except for the new taxon as a terminal node at the top of the 
tree. None of the clade definitions have changed except for the additions of 
new characters. We have the same clades but they now how more precise 
definition.

2. Is it really wise to declare taxa based on scrappy remains nomia dubia 
because they lack a single unique derived character even before we have 
stabil (or at least somewhat exhaustive) definitions  of the taxa they most 
closely resemble?

I recently read an article were three taxa were declared nomia dubia 
eventhough their closest suspected relative lacks a modern description. 
While the results of the article were formally correct under the rules of 
cladistics and the present knowledge of the clade (really a more inclusive 
clade), the taxa might need to be reinstated when the knowledge of the clade 
improves.

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