[Re:] Basal exclusivity

Thomas Schlemmermeyer termites at USP.BR
Tue Apr 11 12:50:50 CDT 2000

The term "basal exclusivity" is new to me. But as far as I know what 
phylogeneticists want to say when they say "basal" is that the group under 
question is supposed to be relatively primitive or generalized. That means that 
it shows many characters of the supposed hypothetical ancestor, that it is an 
early off-shoot close to the root of the tree, and that it may be old and that 
it has not many autapomorphies or that it has very peculiar ones, not shared 
with other members of the more inclusive group. 

On (         Tue, 11 Apr 2000 09:33:33 +1200),         David Orlovich 
<David.Orlovich at BOTANY.OTAGO.AC.NZ> wrote:

>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.
>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

Thomas Schlemmermeyer
Museu de Zoologia, Universidade de São Paulo
Caixa Postal 42694
CEP 04299-970
São Paulo, SP, Brasil

Thomas Schlemmermeyer
Caixa Postal 00276
CEP 14001-970
Ribeirão Preto, SP, Brasil

Fone, Fax: 016 6371999

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