- Volume 69, Issue 8, 2019

The term effective publication and the adjectival form effectively published occur at numerous points in the International Code of Nomenclature of Prokaryotes. As defined in Rule 25a the term refers to a form of publication rather than to names or descriptions. Although names are also defined as being effectively published, which is also defined as a status under the International Code of Nomenclature of Prokaryotes, such names are not automatically validly published and only validly published names can have a status under the Code. If one clearly separates the act of publication of scientific works from other elements of the Code then it is possible to clarify the workings of the Code whereby only names included in scientific works that are published in accordance with Rule 25a may have a status under the Code once they are validly published. Similarly names would then be validly published or not validly published, with the latter, irrespective of where they are found, having no status under the International Code of Nomenclature of Prokaryotes.

The new name at the rank of family Bradyrhizobiaceae Garrity et al. 2006 was created to include the genera Afipia Brenner et al. 1992, Agromonas Ohta and Hattori 1985, Blastobacter Zavarzin 1961 (Approved Lists 1980), Bosea Das et al. 1996, Bradyrhizobium Jordan 1982 (the nomenclatural type), Nitrobacter Winogradsky 1892 (Approved Lists 1980), Oligotropha Meyer et al. 1994, Rhodoblastus Imhoff 2001 and Rhodopseudomonas Czurda and Maresch 1937 (Approved Lists 1980). However, Nitrobacter Winogradsky 1892 (Approved Lists 1980) is the nomenclatural type of Nitrobacteraceae Buchanan 1917 (Approved Lists 1980) a name at the rank of family that was validly published prior to the valid publication of Bradyrhizobiaceae Garrity et al. 2006 and has priority. In addition Rule 51b (1) of the International Code of Nomenclature of Prokaryotes rules that under these circumstances Bradyrhizobiaceae Garrity et al. 2006 is an illegitimate name. Illegitimate names may not be used (Rule 51a) and illegitimate names are also not taken into consideration when determining priority (Rule 23a). Nitrobacteraceae Buchanan 1917 (Approved Lists 1980) is the only correct name (Rule 23a). Despite these facts the name Bradyrhizobiaceae Garrity et al. 2006 continues to be used, perhaps because the fact that it is an illegitimate name and the consequences of that status are not fully understood. A revision of Rule 54 would also appear to be appropriate in order to further emphasise the fact that the family name Bradyrhizobiaceae Garrity et al. 2006 must be replaced by the family name Nitrobacteraceae Buchanan 1917 (Approved Lists 1980), which is the oldest legitimate name and is the only correct name that may be used for the taxon that includes Bradyrhizobium Jordan 1982 and Nitrobacter Winogradsky 1892 (Approved Lists 1980).

In a recent publication dealing with the classification of species assigned to the genus Propionibacterium , evidence was presented supporting that it would be appropriate to sub-divide the genus into four genera, Propionibacterium Orla-Jensen 1909 (Approved Lists 1980) emend. Scholz and Kilian 2016, Acidipropionibacterium Scholz and Kilian 2016, Cutibacterium Scholz and Kilian 2016 and Pseudopropionibacterium Scholz and Kilian 2016. Of these genera, Pseudopropionibacterium Scholz and Kilian 2016 was proposed to contain a single species Pseudopropionibacterium propionicum (Buchanan and Pine 1962) Scholz and Kilian 2016 that is also the nomenclatural type. The nomenclatural type of Pseudopropionibacterium propionicum (Buchanan and Pine 1962) Scholz and Kilian 2016 is also the nomenclatural type of Propionibacterium propionicum corrig. (Buchanan and Pine 1962) Charfreitag et al. 1988 and Arachnia propionica (Buchanan and Pine 1962) [Pine and Georg 1969 (Approved Lists 1980)] and are consequently homotypic synonyms. Arachnia propionica (Buchanan and Pine 1962) Pine and Georg 1969 (Approved Lists 1980) was the nomenclatural type and only species placed within the genus Arachnia Pine and Georg 1969 (Approved Lists 1980). In the light of this fact, the consequences for the names Arachnia propionica (Buchanan and Pine 1962) Pine and Georg 1969 (Approved Lists 1980), Propionibacterium propionicum corrig. (Buchanan and Pine 1962) Charfreitag et al. 1988 and Pseudopropionibacterium propionicum (Buchanan and Pine 1962) Scholz and Kilian 2016 are discussed together with the correct name for the recently validly published name Pseudopropionibacterium rubrum Saito et al. 2018.

The International Code of Nomenclature of Prokaryotes specifically forbids the use of strains deposited solely for patent purposes from serving as nomenclatural types. Despite this ruling there are a number of names at the rank of species where strains deposited solely for patent purposes have been designated as the nomenclatural type. In some cases there is only a single deposit where the strain is deposited solely for patent purposes or there are two or more deposits in culture collections, one (or more) of which is a strain deposited solely for patent purposes. In such instances the requirements of Rule 30 may not be fulfilled and the valid publication of the corresponding names called into question because nomenclatural types have not been deposited in at least two publicly accessible culture collections in different countries.

The list that notifies names published in volume 68, part 1 of the International Journal of Systematic and Evolutionary Microbiology provides the information that a number of names of species in the genus Clavibacter that had previously been treated as names at the rank of subspecies were illegitimate because they contravene Rule 34a and Rule 50a of the International Code of Nomenclature of Prokaryotes. Rule 34a deals with combinations at the same rank and this rule does not apply to names that involve a change in rank. Rule 34a, b and c all fall under the heading new combinations and that in the case of names at the rank of species and subspecies where a change in rank is made Rule 34c applies. Rule 50a applies to names at the rank of subspecies that are elevated to species, but it is unclear why these nomenclatural changes lead to illegitimate names. Fortunately the Code is explicit in stating the role of the Notification Lists is limited to allowing orthographic corrections to be made. It is necessary to publish an interpretation of the status of these names that is consistent with the current wording of the Code.