[Taxacom] Paraphyletic species and paraphyletic higher taxa

[Curtis Clark]

On 12/14/2010 8:17 AM, Chris Thompson wrote:
> first on yours
> "With a clade, you can always say "show me your synapomorphies". A 
> paraphyletic group is argument by authority."
>
> Not exactly as a paraphyletic group is merely clade A minus clade B. A 
> polyphletic group is merely clade A minus clades B, C, etc. So, it is 
> not argument by authority.
But where, exactly, do you draw the line? Because every paraphyletic 
group precludes the existence of many others, that's where it's argument 
by authority. Clades can be nested, and every synapomorphy can diagnose 
a named clade, but one has to choose one paraphyletic group over others 
with slightly larger or smaller excluded clades.

-- 
Curtis Clark                  http://www.csupomona.edu/~jcclark/
Director, I&IT Web Development                   +1 909 979 6371
University Web Coordinator, Cal Poly Pomona