paraphyly

[taxacom]

Dear Thomas,

I'm quite agree: if you divide a higher taxon into natural subgroups, the
subgroups are NOT paraphyletic. This is because the classification is
intensional structure. I only wished to attract attention to the fact that
such subgenera meet cladistic (extensional) definition of paraphyly.

Larissa

----- Original Message -----
From: "Thomas DiBenedetto" <tdib at oceanconservancy.org>
To: "'taxacom'" <taxacom at IBSS.DVO.RU>; <TAXACOM at USOBI.ORG>
Sent: Tuesday, January 22, 2002 5:24 AM
Subject: RE: paraphyly


> -----Original Message-----
> From:Larissa Vasilyeva
> ... suppose, one finds such characters that divide a genus into quite
> natural subgenera. Then, subgenera are paraphyletic extensionally since
they
> do not include all of the original ancestor's descendants, but they are
> monophyletic intensionally
> **********
> No, I disagree with this. If you divide a higher taxon into natural
> subgroups, the subgroups are NOT paraphyletic. For example, Mammalia is a
> monophyletic higher taxon (let's make the analogy to your "genus").
Primates
> is a monophyletic sub-taxon (analagous to your "natural sub-genus"). Is
> Primates paraphyletic because it does not include the ancestral mammal?
No,
> of course not. Critters that are Primates are also Mammals. Primates is
> monophylteic because it includes the ancestral Primate - it neednt
containt
> the ancestral Mammal, or Animal or Eukaryote.
> *************
> Thus subgenera are monophyletic and paraphyletic simultaneously,
> ************
> Sorry, not possible -
>
> Tom diBenedetto
>
>