title: Are Rules 20d and 20e of the International Code of Nomenclature of Prokaryotes superfluous?
abstract: The wording of Rule 20d and 20e of the 1975, 1990 and 2008 revisions of the International Code of Nomenclature of Bacteria/Prokaryotes deals with problems that may arise when the nomenclatural type of a genus was not designated or when there are problems determining what the nomenclatural type should be. However, Rule 16 states that a nomenclatural type must be designated, while Rule 27 clearly states that a requirement of valid publication is the designation of a type for a new taxon and this is reinforced under Rule 29 that deals with the valid publication of a genus or subgenus name. Furthermore, the wording of Rule 18a and Rule 30 strongly suggests that the type of problem envisaged with regards the species included in the genus should no longer occur. The wording of Rule 20d and 20e appears to have originated in earlier revision of the International Code of Nomenclature of Bacteria and may no longer be relevant in the 1975, 1990 and 2008 revisions due to significant changes made in those revisions.
authors.affiliation: Leibniz-Institut DSMZ-Deutsche Sammlung von Mikroorganismen und Zellkulturen GmbH, Inhoffenstraße 7B, 38124 Braunschweig, Germany.
authors.forename: B J
authors.initials: BJ
authors.lastname: Tindall
mesh_terms: D001419:Bacteria / Q000145:classification*; D009626:Terminology as Topic