Autapomorphy

[Michael Ivie]

Dear Vernie,

Autapomorphies are, by definition, not informative at the level of
universality under investigation, but the character state may be
informative at other levels of universality (by definition no longer an
autapomorphy).  If "level of universality" is an unfamiliar term, please
refer to basic textbooks such as Wiley, E. O.  1981.  Phylogenetics.
Wiley & Sons New York.  Also, your definition of autapomorphy is
incorrect.  See the same reference for a correct definition.  I am sure
there are many copies of this reference kicking around the Survey staff
offices.

Mike

On Wed, 15 Sep 2004, Vernie Sagun wrote:

> Dear Taxacomers,
> I would like to ask about the term "autapomorphy", as I
> understand this is a character state present in a taxon that
> is not present in other taxa and is therefore
> phylogenetically uniformative.  Autapomorphies are very
> useful in creating keys and not useful in resolving
> phylogeny.  But I have heard other views that say this is a
> relative term, that clades could have a character state that
> is "autapomorphic" for that clade, in the case of broader
> (highly speciose or in ordinal level) phylogenies.  I believe
> this is a misuse of the term since that "autapomorphic"
> character state for that clade, is more appropriate to be
> called a "synapomorphy".  The term autapomorphy can never be
> realtive.  Can you help me clarify this?
>
> Many thanks,
> Vernie Sagun
>
> *******************************
> VERNIE G. SAGUN
> Center for Biodiversity
> Illinois Natural History Survey
> 607 E. Peabody Dr.,
> Champaign, IL 61820-6970
> U.S.A.
> Tel: (217)244 9220
> Fax: (217)244 0729
> email: sagun at uiuc.edu
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>