More taxo-computational distractions

Thomas Schlemmermeyer termites at USP.BR
Tue Dec 2 19:02:08 CST 1997

Hello, it's a very exciting discussion, so far, I'm awaiting more examples =
windows to the past,

But: Magnus Liden wrote

> Hej svejs Thomas Schlemmermeyer <termites at USP.BR>,

OK, I guess this is swedish=20

> The term "basal" appplied to a cladogram/phylogenetic tree only designate=
> a clade (or OTU) that is sistergropup to a large and speciose (or better:
> OTU-ose) clade in an assymetric tree. It bears no connotation what-so-eve=
> to degree of "primitiveness". Only CHARACTERS can be labelled plesio- or
> apomorphic, not TAXA! An isolated "basal" branch should be expected to be
> on average just as "advanced" as any other OTU. There is no logical or
> biological reason to expect a priori that some OTUs are more "archaic" or
> "generalized" than others.

What are OTU and OTU-ose????
Is the word taxon not sufficient to cover all difficulties?????

I re-read HENNIG's 1953 paper (Kritische Bemerkungen zum phylogenetischen
System der Insekten). HENNIG used, in fact, the terms plesiomorphic and=20
apomorphic referring not only to characters, but also to taxa. But this was
in 1953, maybe, later, he changed later the terminology, I do not know.

One of the central, theoretical problems in HENNIG's 1953 paper is
that some taxa are well defined on the ground of many synapomorphies,
while the apparent sister-taxa are not well defined due to the lack of
synapomorphies. These are plesiomorphic taxa which have to be worked
out better.

Again, I do not know what are OTUs, but I do think that there are mountains
of logical and biological reasons to consider some taxa more archaic than
These mountains you may find in your library.=20
Systematics are not starting from a point zero, but erect their hypotheses
in a already existing, a priori framework.

OK, are there more examples of windows to the past?

Thanks und Tschuess    Thomas
Thomas Schlemmermeyer
Museu de Zoologia, Universidade de S=E3o Paulo
Caixa Postal 42694
CEP 04299-970
S=E3o Paulo, SP, Brasil

Thomas Schlemmermeyer
Caixa Postal 00276
CEP 14001-970
Ribeir=E3o Preto, SP, Brasil

Fone, Fax: 016 6371999

More information about the Taxacom mailing list