incertae sedis vs. sedes

[Martin Spies]

Peter Bostock wrote:
> the phrase "incertae sedis" is in the genitive singular hence "of uncertain
> position"
Agreed

> so you would need to say "incertarum sedium" for a genitive
> plural rendition.
> I can't see any reason not to use the plural phrase if you consider it
> applicable. Just a matter of grammar after all.
I see two reasons not to use "incertarum sedium":

1) The term is to stand for an abstract status condition, not a
feature observable on several individuals and viewed as a plural (such
as, e.g. '10 pairs of legs'). For this reason, the English phrase is
used in the singular only (nobody says 'these five taxa are of
uncertain positions'), therefore the Latin phrase should remain in the
singular also.

2) I've never seen "incertarum sedium" anywhere, and would avoid
potential confusion on the reader's part by the needless introduction
of needless variation that to most readers will not be intuitively
understandable (it even wasn't to the prospective author  ;-)  ).
For example, in the International Code of Zoological Nomenclature you
can find "incertae sedis" explained in the Glossary, but not the
plural form.

Best regards,

--
Martin Spies
c/o Zoologische Staatssammlung Muenchen
Germany