Re: monophyletic; polyphyletic; paraphyletic

["Ken Kinman" <kinman@hotmail.com>]

    A paraphyletic group also stems from a most recent common (basal) 
ancestor, but one or more exgroups have been formally removed (that is why 
strict cladists dislike them, because they are "incomplete").
    Dinosauria is paraphyletic if you formally remove Aves.  Amphibia 
(traditional, sensu lato) is paraphyletic if you formally remove Amniota.  
Hypsilophodontidae (sensu lato) is paraphyletic if you remove the 
dryomorphs.
    My solution to this dilemma of "incompleteness" is to add {{markers}} 
for exgroups, so that paraphyletic groups become cladistically complete in 
informational terms.  Family Hypsilophodontidae is paraphyletic, but adding 
the marker for dryomorphs {{Dryosauridae to Hadrosauridae}} effectively 
makes it strictly monophyletic (ie. holophyletic).
     I call such "marked" groups semi-paraphyletic or semi-holophyletic 
(both mean the same thing, sort of like half-empty or half-full).  By the 
way, holophyletic is the proper term for cladistically "monophyletic".  The 
pre-cladistic meaning of monophyletic meant holophyletic and/or paraphyletic 
(i.e. have a common recent ancestor, whether any exgroups have been removed 
or not).  I personally wish the term monophyletic would be abandoned, 
because holophyletic is more precise (while monophyletic means something 
different to cladists and non-cladists).
               --------Ken Kinman
******************************************
> From: "aspidel" <aspidel@infonie.be>
> Reply-To: aspidel@infonie.be
> To: "The Dinosaur Mailing List" <dinosaur@usc.edu>
> Subject: monophyletic; polyphyletic; paraphyletic
> Date: Mon, 20 Aug 2001 22:43:07 +0200
>
> Hi dear dino-list members,
>
> First thanks to HP's Ken Kinman and Thomas R. Holtz Jr.'s replies.
>
> Another question:
>
> monophyletic: is it told about a group which is derived from a common basal 
> species?
>
> polyphyletic: is it told about a group which contains species sharing 
> common features but which may derive from different basal species?
>
> And what means paraphyletic?
>
> Many thanks in advance, friendly - LJB.
>
> ps: maybe I'm not clear; and excuse my bad English.


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