Are the concepts of legitimate and illegitimate names necessary under the current International Code of Nomenclature of Bacteria? A proposal to make changes to the Code

Section 8 also deals with illegitimate names. However, it is clear that the wording is not always in accord with the underlying definitions, or that one may simply replace the concept of illegitimate names with the requirement that only names that are in accordance with the Code may be validly published. The problem then arises that it would appear that an illegitimate name may be validly published, but at the same time such a name cannot be used as a correct name. Thus, one is left with the paradox that there are instances where a taxon is given a validly published name but, because it is illegitimate, that name cannot be used. In the majority of cases, the situation would be clarified if only names that are in accordance with the Rules can be validly published, thus making the terms legitimate and illegitimate superfluous. In addition, this would have the effect of removing an ambiguity in the Code. Some changes to the wording of the Code with regards the use of the terms legitimate/illegitimate have been accepted by the Judicial Commission and the International Committee on Systematics of Prokaryotes (ICSP) (De Vos & Trüper, 2000; Tindall et al., 2008).


Rule 20a
'The nomenclatural type of a genus or subgenus is the type species, that is, the single species or one of the species included when the name was originally validly published.Only species whose names are legitimate may serve as types.' This may be changed to: 'The nomenclatural type of a genus or subgenus is the type species, that is, the single species or one of the species included when the name was originally validly published.Only species whose names are validly published may serve as types.'

Rule 21a
'The nomenclatural type of a taxon above genus, up to and including order, is the (legitimate name of the [included] genus on whose name) genus on whose name the name of the relevant taxon is based.One taxon of each category must include the type genus.The names of the taxa which include the type genus must be formed by the addition of the appropriate suffix to the stem of the name of the type genus (see Rule 9).' This may be changed to: 'The nomenclatural type of a taxon above genus, up to and including order, is the (validly published name of the [included] genus on whose name) genus on whose name the name of the relevant taxon is based.One taxon of each category must include the type genus.The names of the taxa which include the type genus must be formed by the addition of the appropriate suffix to the stem of the name of the type genus (see Rule 9).'

Rule 23b
'The date of a name or epithet is that of its valid publication.For purposes of priority, however, only legitimate names and epithets are taken into consideration (see Rules 32b and 54).' This may be changed to: 'The date of a name or epithet is that of its valid publication.For purposes of priority, however, only validly published names and epithets are taken into consideration (see Rules 32b and 54).'

Rule 31a
'The name of a species or a subspecies is not validly published if the description is demonstrably ambiguous and cannot be critically identified for purposes of the precise application of the name of a taxon.
Examples: 'Methanobacillus omelianskii', whose description included all component species, was treated as a single species and was thus illegitimate.
Syntrophobacter wolinii (Boone and Bryant 1984) is legitimate, because the species description applies to one member of the syntrophic association with a hydrogen-producing organism.' This may be changed to: 'The name of a species or a subspecies is not validly published if the description is demonstrably ambiguous and cannot be critically identified for purposes of the precise application of the name of a taxon.
Examples: 'Methanobacillus omelianskii', whose description included all component species, was treated as a single species and was thus not validly published.Syntrophobacter wolinii Boone and Bryant 1984 is validly published, because the species description applies to one member of the syntrophic association with a hydrogen-producing organism'.et al., 1992).

Rule 47a
'When two or more taxa of the same rank from subtribe to family inclusive are united under a taxon of higher rank, the higher-ranking taxon should derive its name from the name of the earliest legitimate genus that is a type genus of one of the lower-ranking taxa.' This may be changed to: 'When two or more taxa of the same rank from subtribe to family inclusive are united under a taxon of higher rank, the higher-ranking taxon should derive its name from the earliest validly published genus name that is a type genus of one of the lowerranking taxa.'

Rule 50a
'When a subspecies is elevated in rank to a species, the subspecific epithet in the name of the subspecies must be used as the specific epithet of the name of the species unless the resulting combination is illegitimate.
Example This may be changed to: 'When a species is lowered in rank to a subspecies, the specific epithet in the name of the species must be used as the subspecific epithet of the name of the subspecies unless the resulting combination is contrary to the Rules.The example given is misleading, since it relates to an incorrect taxonomic interpretation.Once a name is legitimate (or validly published) it should remain so, unless it becomes a rejected name.Creating a combination that is contrary to the Rules does not affect the status of the original genus names or the epithets, although the creation of any new combinations would make those combinations illegitimate or, as proposed here, not validly published.
The wording of Rule 51a may be simplified as follows: 'A name contrary to a Rule may not be validly published.'

Rule 51b
'Among the reasons for which a name may be illegitimate are the following.
(1) If the taxon to which the name was applied, as circumscribed by the author, included the nomenclatural type of a name which the author ought to have adopted under one or more of the Rules.
Example: If an author circumscribes a genus to include Bacillus subtilis, the type species of the genus Bacillus, then the circumscribed genus must be named Bacillus.
(2) If the author did not adopt for a binary or ternary combination the earliest legitimate generic name, specific epithet, or subspecific epithet available for the taxon with its particular circumscription, position, and rank.
Example: The name Bacillus whitmori Bergey et al.
1930 was illegitimate as Whitmore had named the organism Bacillus pseudomallei in 1903.
(3) If its specific epithet must be rejected under Rules 52 or 53.
( This may be changed to: 'Among the reasons for which a name is contrary to the Rules are: (1) If the taxon to which the name was applied, as circumscribed by the author, included the nomenclatural type of a name which the author ought to have adopted under one or more of the Rules.
Example: If an author circumscribes a genus to include Bacillus subtilis, the type species of the genus Bacillus, then the circumscribed genus must be named Bacillus.
(2) If the author did not adopt for a binary or ternary combination the earliest validly published generic name, specific epithet or subspecific epithet available for the taxon with its particular circumscription, position and rank.
Example: The name Bacillus whitmori Bergey et al.
1930 cannot be validly published as Whitmore had named the organism Bacillus pseudomallei in 1903.
(3) If its specific epithet must be rejected under Rules 52 or 53.
( Due consideration should be given to the fact that it may be sensible to alter the wording of the Code to clarify whether a species or subspecies epithet may be validly published if, at the time they were created, the genus name and resulting combination are not validly published.

Rule 55
'A legitimate name or epithet may not be replaced merely because of the following.' This may be changed to: 'A validly published name or epithet may not be replaced merely because of the following.'

Rule 56b
'A conserved name (nomen conservandum) is a name which must be used instead of all earlier synonyms and homonyms.
Note 1.A conserved name (nomen conservandum) is conserved against all other names for the taxon, whether these are cited in the corresponding list of rejected names or not, so long as the taxon concerned is not united with another taxon bearing a legitimate name.In the event of union or reunion with another taxon, the earlier of the two competing names is adopted in accordance with Rules 23a, b.
Note 2. Only the Judicial Commission can place names on the list of conserved names (nomina conservanda) (see also Rule 23a, Note 4, and Appendix 4).' This may be changed to: 'A conserved name (nomen conservandum) is a name which must be used instead of all earlier synonyms and homonyms.
Note 1.A conserved name (nomen conservandum) is conserved against all other names for the taxon, whether these are cited in the corresponding list of rejected names or not, so long as the taxon concerned This may be changed to: 'The correct name of a taxon is based upon valid publication and priority of publication (see Chapter 3, Section 5).'

Consequences
The proposals listed above would have the effect of making those names that are currently considered to be illegitimate not validly published.It is evident that a number of names already contravene the Code and, although they are illegitimate, they are in widely accepted usage.An undesirable effect of the change in wording would be to make a number of names in common usage not validly published.In such cases, the Judicial Commission can set aside the Rules of the Code and make exceptions as laid down by Rule 3 of the Code (Lapage et al., 1992).This course of action is strongly recommended where appropriate.Some examples are given below.

The genus name Rhizomonas
The name is associated with a protist genus Rhizomonas Kent 1880 (although this name is not a name in current usage in botany: see http://botany.si.edu/ing/ and http:// www.bgbm.org/iapt/ncu/genera/NCUGQuery.htm) and is associated with the prokaryote genus 'Rhizomonas' Orla-Jensen 1909 (Buchanan et al., 1966).The prokaryote genus name appears in Opinion 14 (Lapage et al., 1992) as a rejected name.The name 'Rhizomonas' Orla-Jensen 1909 is not considered to be a homonym according to Rule 51b (4) (Lapage et al., 1992) Yabuuchi et al. 1990(van Bruggen et al., 1990;Yabuuchi et al., 1990aYabuuchi et al., , b, 1999a, b), b).Due consideration should also be given to whether a species or subspecies epithet can be validly published if the genus name and resulting combination are not validly published (see additional text under Rule 54).In this form, the citation of the names would not make reference to names (or epithets) that are not validly published, but reference may, of course, be made to a previously effective publication of a description in van Bruggen et al. (1990) in the protologue that appears in Yabuuchi et al. (1999a), which would be indirectly referenced via publication of the name on Validation List 70 (Yabuuchi et al., 1999b), and this interpretation conforms to the wording of Rule 27.However, it would have an influence on the date of priority of the epithet.
If it is a later homonym of a name of a taxon of prokaryotes, fungi, algae, protozoa, or viruses.Example: If no validly published name or epithet exists, one must be chosen.Since a specific epithet is not rendered not validly published by publication in a species name in which the generic name is not validly published (Rule 32b), an author may use such an epithet if he wishes, provided that there is no obstacle to its employment in the new position or sense; the resultant combination is treated as a new name and is to be ascribed to the author of the combination.The epithet is, however, ascribed to the original author.When a new species or a new combination results in the proposal of a new genus, both the genus name and the new species name or new combination must be validly published.Valid publication of the new species or new combination alone does not constitute valid publication of the new genus.' Example: Corynebacterium helvolum (Zimmermann 1890) Kisskalt and Berend 1918 is based on the type IP: 54.70.40.11On:Thu, 06 Dec 2018 22:11:52is not united with another taxon bearing a validly published name.In the event of union or reunion with another taxon, the earlier of the two competing names is adopted in accordance with Rules 23a, b.
. It has, however, been used again as Rhizomonas van Bruggen et al. 1990, although the name remains illegitimate.The combination Rhizomonas suberifaciens van Bruggen et al. 1990 is also illegitimate, although, according to Rule 53, the epithet is not illegitimate.This taxon has been transferred to Sphingomonas suberifaciens (van Bruggen et al., 1990) Yabuuchi et al. 1999.However, if the relevant Rules were to be changed to dispose of the principle of illegitimate and legitimate names and to require that only names in accordance with the Rules can be validly published, there would be a number of consequences.The genus name Rhizomonas van Bruggen et al. 1990 is also an earlier heterotypic synonym of the genus name Sphingomonas