The principal categories 'kingdom' and 'domain', which are above the phylum rank, were recently
included in the International Code of Nomenclature of Prokaryotes (ICNP). Similarly, official virus nomenclature was
augmented by several principal categories, including 'kingdom' and 'realm'. Apparently, 'realm' and 'domain' represent the same principal rank directly above 'kingdom'. If so, the viral hierarchy is compatible with the
ICNP and the botanical code, which goes up to the rank of
kingdom, and the zoological code, which does not formally regulate these high ranks but mentions 'kingdom' as the highest rank in its
glossary. In brief, the sequence of principal ranks is this:
? > domain/realm > kingdom > phylum/division > class > order > family > genus > speciesFurther harmonization may be warranted to reduce confusion. One would expect at least one principal category above the rank of 'domain' or 'realm', and at least one taxon at that rank comprising everything. Some databases have already introduced this informally. Irrespective of whether that category and that taxon could be included in a code of nomenclature, how should they actually be called? If there were only one taxon at the highest rank, including viruses as well as cellular organisms, should its name be more general or specifically indicate something living? How should the term 'empire', which is
used in older literature to denote high ranks but is not included in a code, be treated?
The
three simple questions in this
anonymous survey, initiated by
LPSN and friends, attempt to clarify these issues. Results will be published by LPSN once enough responses have been received.