cf./aff.

[Barry Roth]

My understanding is practically the same as Jan's -- "cf." simply suggests a
comparison with the named species; the specimen might be that species or
it might not.  "aff." means the specimen is something like the named species
but _not_ that species.  For this reason, there is more information content
in "aff." than in "cf."  Left undefined in the common use of "aff." is the
nature of the relationship to the named species.  Is it phylogenetically
related, ore merely "related" in physical similarity?  Perhaps the differ-
ence between these two kinds of "relation" was not even appreciated by the
inventors of "aff."  It is, however, of moment to practitioners of
phylogenetic systematics -- who might not wish to use "aff." loosely for
that reason.

Barry Roth