Basal exclusivity

[David Orlovich]

Hello Taxacom people.  I've been reading a bit on phylogenetic
species concepts and am having trouble understanding 'basal
exclusivity'.  Can anyone enlighten me?  From what I can work out, a
group is basal if all it's members are more closely related to each
other than to others, and exclusive if it contains no other less
inclusive group.  I can't understand what the difference is between
this and saying that a species is monophyletic and has
autapomorphies.  I am wondering if using the terms basal and
exclusive are just a way of avoiding cladistic terminology - but then
I would have thought that to determine basal exclusivity would
require a phylogenetic analysis of individuals anyway.  The term
basal seems also to be confusing since it seems to refer to a
terminal taxon in the 'basal exclusivity' sense and to something
quite different in a cladistic sense.  Any help appreciated!  Cheers,
David Orlovich.

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__________________________________
Dr David Orlovich
Department of Botany,
The University of Otgao
PO Box 56,
Dunedin, New Zealand.

Telephone: +643 479 9060
Fax: +643 479 7583
WWW: http://www.otago.ac.nz/botany/
email: david.orlovich at botany.otago.ac.nz