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Judicial Opinions112–122
David R.Arahal1, Hans- JürgenBusse2, Carolee T.Bull3, HenrikChristensen4, MariaChuvochina5, Svetlana
N.Dedysh6, Pierre- EdouardFournier7, Konstantinos T.Konstantinidis8, Charles T.Parker9, RamonRossello- Mora10,
AntonioVentosa11 and MarkusGöker12,*
ICSP - OPINION
Arahal etal., Int. J. Syst. Evol. Microbiol. 2022;72:005481
DOI 10.1099/ijsem.0.005481
Author aliations: 1Departamento de Microbiología y Ecología, Universitat de València, Valencia, Spain; 2Institut für Mikrobiologie, University of
Veterinary Medicine, Veterinärplatz 1, A- 1210 Wien, Austria; 3Department of Plant Pathology and Environmental Microbiology, Pennsylvania State
University, 211 Buckhout Lab, University Park, PA 16802, USA; 4Department of Veterinary and Animal Sciences, University of Copenhagen, Stigbøjlen 4,
1870 Frederiksberg C, Denmark; 5The University of Queensland, School of Chemistry and Molecular Biosciences, Australian Centre for Ecogenomics,
QLD 4072, Australia; 6Winogradsky Institute of Microbiology, Research Center of Biotechnology RAS, Prospect 60- letya Octyabrya 7/2, Moscow 117312,
Russia; 7UMR VITROME, IHU - Méditerranée Infection, 19- 21 Bd Jean Moulin, 13005 Marseille, France; 8School of Civil & Environmental Engineering
and School of Biological Sciences, Georgia Institute of Technology, Atlanta, Georgia, USA; 9NamesforLife, LLC,East Lansing, East Lansing, Okemos,
Michigan 48805- 0769, USA; 10Department of Animal and Microbial Biodiversity, Institut Mediterrani d’Estudis Avançats, CSIC- UIB, C/Miquel Marqués 21,
07190 Esporles, Illes Balears, Spain; 11Department of Microbiology and Parasitology, Faculty of Pharmacy, University of Sevilla, Sevilla, C/. Prof. Garcia
Gonzalez 2, ES- 41012 Sevilla, Spain; 12Leibniz Institute DSMZ – German Collection of Microorganisms and Cell Cultures, Inhoenstrasse 7B, D- 38124
Braunschweig, Germany.
*Correspondence: Markus Göker, markus. goeker@ dsmz. de
Abbreviations: DDH, DNA–DNA hybridization; ICNP, International Code of Nomenclature of Prokaryotes; ICSP, International Committee on Systematics
of Prokaryotes; OTU, operational taxonomic unit.
005481 © 2022 The Authors
Abstract
Opinion 112 denies the request to place Seliberia Aristovskaya and Parinkina 1963 (Approved Lists 1980) on the list of rejected
names because the information provided is insucient. For the same reason, Opinion 113 denies the request to reject She-
wanella irciniae Lee et al. 2006 and Opinion 114 denies the request to reject the name Enterobacter siamensis Khunthongpan et
al. 2014. Opinion 115 rejects the epithet of Moorella thermoautotrophica (Wiegel et al. 1981) Collins et al. 1994, which is regarded
as a nomen confusum. To assess the consequences of Rule 8, Opinion 116 revisits names of taxa above the rank of genus which
should comprise the stem of the name of a nomenclatural type and a category- specific ending but fail to do so. Such names
should be orthographically corrected if the sole error is the inadvertent usage of an incorrect stem or be regarded as illegiti-
mate if otherwise. The necessary corrections are made for a number of names. In Opinion 117, the request to designate Methy-
lothermus subterraneus Hirayama et al. 2011 as the type species of the genus Methylothermus is denied because an equivalent
action compatible with the Code was already conducted. In Opinion 118, the possible orthographical correction of the name
Flaviaesturariibacter is treated, as are the analogous cases of Fredinandcohnia and Hydrogeniiclostidium. The genus names are
corrected to Flaviaestuariibacter, Ferdinandcohnia and Hydrogeniiclostridium, respectively. Opinion 119 concludes that assigning
Actinomycetales Buchanan 1917 (Approved Lists 1980) as nomenclatural type of the class Actinobacteria Stackebrandt et al.
1997 would not render that name legitimate if Rule 8 remained retroactive. The request is granted but Actinomycetales is also
assigned as type of Actinomycetes Krassilnikov 1949 (Approved Lists 1980). In Opinion 120, the possible orthographical cor-
rection of the name Amycolatopsis albidoflavus is treated. It is grammatically corrected to Amycolatopsis albidoflava. Six names
which could according to Rule 61 be grammatically corrected by anyone are also corrected. Opinion 121 denies the request to
revise Opinion 69 and notes that Opinion 69 does not have the undesirable consequences emphasized in the request. In Opinion
122, the request to reject various taxon names of Mollicutes proposed in 2018 is denied because it is based on misinterpreta-
tions of the Code, which are clarified. Alternative ways to solve the perceived problems are outlined. These Opinions were rati-
fied by the voting members of the International Committee on Systematics of Prokaryotes.
OPINION 112
A Request for an Opinion was raised by Velázquez et al. [1] regarding the status of the species Seliberia stellata, and subsequently
of the genus Seliberia Aristovskaya and Parinkina 1963 (Approved Lists 1980) [2–4], based on results obtained with molecular
data, namely 5S and 16S rRNA gene sequence comparison and matrix- assisted laser desorption/ionization- time of ight MS
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Arahal etal., Int. J. Syst. Evol. Microbiol. 2022;72:005481
analysis. e authors interpret that deposits CECT 7960 and VKM B- 1340, supposed to represent the type strain of Seliberia
stellata, do not descend from the originally designated type strain (INMI N- 9) and should be identied as representatives of the
species Bradyrhizobium betae. Following this interpretation, the authors proposed four actions for the Judicial Commission:
(1)
at the organism currently deposited as VKM B- 1340 and CECT 7960 be recognized as a member of the species Bradyrhizo-
bium betae.
(2) at the organism deposited as VKM B- 1340 and CECT 7960 does not represent the type strain of the species Seliberia
stellata.
(3) To place the species name Seliberia stellata Aristovskaya and Parinkina 1963 (Approved Lists 1980) on the list of rejected
names if a suitable replacement strain, or neotype, cannot be found within 2 years of publication of this Request (Rule 18c) [5].
(4) To place the genus name Seliberia Aristovskaya and Parinkina 1963 (Approved Lists 1980) on the list of rejected names
(nomina rejicienda, Recommendation 20d) [5] if a suitable replacement type strain, or neotype, for the type species of the
genus Seliberia Aristovskaya and Parinkina 1963 (Approved Lists 1980) is not identied as indicated in point 3.
e rst proposed action is a matter of classication that does not require the consultation of the Judicial Commission.
e second proposed action requires that the decision is based on the characteristics of the description that accompanies the valid
publication. e names Seliberia and Seliberia stellata were validated in the Approved Lists 1980 [4] and according to this source,
their descriptions as genus and species respectively are to be found in the eighth edition of Bergey’s Manual of Determinative
Bacteriology [3]. So, while 16S rRNA gene and 5S rRNA gene sequencing may be valuable tools, the primary data set on which
earlier descriptions were based did not include those data. Since the original description has not been later emended, for example
to include accession numbers of sequences or in any other way, the properties of the taxon that need to be considered are those
in the aforementioned description [3]. Unfortunately, the Request for an Opinion clearly fails to do this.
e third proposed action reproduces a previously observed misinterpretation of Rule 18c of the International Code of
Nomenclature of Prokaryotes (ICNP) [5], an issue that has been already reviewed [6]. Because of this and in the absence of
other data, it is not possible to take any action. One scenario could be that the properties of deposits VKM B- 1340 and CECT
7960 agree closely with the description of the species Seliberia stellata [3] meaning that they can be regarded as deposits of
the type strain, according to Rule 18a [5]. e taxonomic implications of this would be a matter of classication open to any
interested party. Another scenario would be that such agreement is not found, meaning that deposits VKM B- 1340 and CECT
7960 cannot be considered to be derived from INMI N- 9 and that a neotype may be proposed in accordance with Rule 18c
[5]. In this sense the following comment in the species description [3] gives some indication about the feasibility of nding
a suitable neotype strain:
“Hirsch (unpublished) has found Seliberia spp. in laboratory distilled- water and in surface layers of a small forest pond.”
e evidence provided thus far discards any scenario as plausible for rejection of the names as considered in Rule 56a [5].
Finally, the fourth proposed action cites Recommendation 20d [5] but its wording does not seem to be applicable here as it refers
to reasons for excluding a species from consideration in selecting the type, which is not the case. Aside from the incorrect citation,
the action is linked to the fate of the previous one and so it is denied as well.
In conclusion, the Request for an Opinion by Velázquez et al. [1] contains four elements, as indexed by the authors themselves,
leading to the rejection of the names Seliberia stellata Aristovskaya and Parinkina 1963 (Approved Lists 1980) and Seliberia
Aristovskaya and Parinkina 1963 (Approved Lists 1980). e Judicial Commission denies this request considering that the data
provided are insucient as they do not consider the accompanying descriptions of the genus and species and without that it is
not possible to make any elucidation of the appropriate course of action. Eleven commissioners favoured this conclusion, one
commissioner opted for granting the request.
OPINION 113
In a Request for an Opinion, Rameshkumar [7] proposed placing the name Shewanella irciniae Lee et al. 2006 [7, 8] on the list
of rejected names.
is request is based on the observation that the type strain, UST040317- 058T (=JCM 13528T=NRRL B- 41466T) is no longer
available from the Japanese Culture Collection (JCM), and that the cultures supposed to represent the type strain Rameshkumar
received from the Agricultural Research Service collection (NRRL) and from Lee et al. [8] were apparently members of the genus
Brevibacillus. erefore Rameshkumar [7] proposed placing the name Shewanella irciniae Lee et al. 2006 on the list of rejected
names if no replacement was found within 2 years.
In the rst place, we see again a misinterpretation of Rule 18c of the ICNP [5] that has been already addressed by Tindall [6] and
several Judicial Opinions [9, 10]. ere is no time limit set in the ICNP for proposing a neotype strain.
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Arahal etal., Int. J. Syst. Evol. Microbiol. 2022;72:005481
From this point, discussion has been extensive and shaped by the fact that the evidence provided is limited. erefore, three
scenarios appear to be possible.
First, since Rameshkumar identied NRRL B- 41466T and UST040317- 058T as belonging to the genus Brevibacillus, it might be
wondered whether the cultures deposited in collections as Shewanella irciniae were really Shewanella irciniae or a Brevibacillus
strain. If an authentic type strain of Shewanella irciniae was never deposited in culture collections, then the name would not
meet the requirements for valid publication as stated in Rule 27(3) in conjunction with Rule 30(3). is situation could not be
rectied by assigning a neotype.
Second, it is possible that the cultures deposited as strain UST040317- 058
T
in collections under references JCM 13528
T
and NRRL
B- 41466T were Shewanella irciniae as described by Lee et al. [8] but were subsequently lost. en it is relevant that a neotype strain
for Shewanella irciniae may be found. is scenario is compatible with the viability loss reported from JCM but it is certainly
not likely in view of the 16S rRNA gene sequence data from the subcultures supplied by NRRL and the original authors [7].
Unfortunately, the Request for an Opinion does not clearly state whether the 16S rRNA gene sequences obtained from the two
cultures were identical, nor are International Nucleotide Sequence Database Collaboration (INSDC) accession numbers provided
that enable others to re- run the analyses. e request does neither provide any phenotypic data to help assist in formulating a
hypothesis, leaving much to conjecture.
In an attempt to locate a potential representative of Shewanella irciniae that could, eventually, be proposed as neotype strain, a
n comparison was conducted using the 16S rRNA sequence from Shewanella irciniae strain UST040317- 058
T
(DQ180743).
e highest sequence similarity (98.9 %) was obtained to Shewanella sp. strain JZ11IS74, described as being isolated from the
surface of a marine sponge, like the Shewanella irciniae type strain. e depositor of the 16S rRNA sequence of strain JZ11IS74 in
GenBank (accession number KC429938.1), Russell Hill, was contacted by the Judicial Commission and was able to revive strain
JZ11IS74. erefore, it appears to be possible to locate a strain that would be genetically close enough to Shewanella irciniae to
serve as neotype strain. However, identication of a strain that is genetically close to Shewanella irciniae does not guarantee that
this strain matches the characteristics given in the original description of Shewanella irciniae, the species described by Lee et al. [8].
Indeed, while the 16S rRNA gene was analysed [8], the proper description (protologue) in the eective publication of Shewanella
irciniae did not mention a sequence accession number. It may thus also be that just the originally published 16S rRNA gene
sequence is wrong. is could have yielded a taxonomically questionable assignment to the genus Shewanella while the rest of
the data were consistent and as required. However, the phenotypic information given in the description of Shewanella irciniae
diers from Brevibacillus strains in several characteristics [11], including its Gram- negative staining, culture growth on 6 % NaCl
agar, culture on and marine agar, and high content of the saturated straight- chain fatty acid C16 : 0 but low content of anteiso- C15 : 0.
For this reason, the phenotypic properties and the 16S rRNA gene sequence given by Lee et al. [8] are consistent in not pointing
to a representative of the genus Brevibacillus.
ird, it cannot entirely be ruled out that the examined type strain was a mixed culture, which could explain why distinct 16S
RNA gene sequences were obtained. In the case of a mixed culture the name could be rejected as a nomen confusum according
to Rule 56a(3). Although the data presented by Rameshkumar [7] are scarce, the fact that this possibility is not even mentioned
makes it very unlikely.
While one commissioner abstained, two commissioners opted for interpreting the name Shewanella irciniae as not validly
published because its type strain was not deposited in two culture collections at the time of publication according to Rule 27(3)
in conjunction with Rule 30(3). Precedents for such a scenario are Judicial Opinions 98, 99, 109 and 110 [9, 10]. However, nine
commissioners voted for denying the request based on the conclusion that in this specic case insucient information was
provided to distinguish between the relevant possibilities. A precedent is Judicial Opinion 108 [10].
OPINION 114
e Request for an Opinion by Kämpfer et al. [12] raises the problem that the type strain of Enterobacter siamensis
Khunthongpan et al. 2014 appears to have been lost or misplaced. e name was proposed by Khunthongpan et al. [13]
and appeared in Validation List No. 159 [14]. e authors of the request compared 16S rRNA gene sequences of deposited
type strains of Enterobacter siamensis (KCTC 23282T=NBRC 107138T) and found high divergence to the sequence depos-
ited with GenBank/EMBL/DDBJ under accession number HQ888848 representing the original strain C2361T reported by
Khunthongpan et al. [13].
e authors of the request also determined the 16S rRNA gene sequence of the original strain C2361T obtained from the authors
[13] and conrmed its identity to those of two deposited strains (KCTC 23282
T
=NBRC 107138
T
) but found ‘numerous discrepan-
cies’ from the originally determined version of the 16S rRNA gene sequence of the same strain (HQ888848). ey found the 16S
rRNA gene sequences of strain C2361T and the deposited strains (KCTC 23282T=NBRC 107138T) to be nearly identical to that
within the genome sequence CP001918 from the type strain of Enterobacter cloacae subsp. cloacae.
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Arahal etal., Int. J. Syst. Evol. Microbiol. 2022;72:005481
e authors of the request [12] assume that the original strain on which the description of the species Enterobacter siamensis
is based has been lost. e authors of the request propose that the species is placed on the list of rejected names if a suitable
replacement of the type strain is not found or a neotype strain not proposed within a time of 2 years. e latter possibility is not
relevant since it is a misinterpretation of Rule 18c. Rule 18c is not directly involved in the rejection of names, which is regulated
by Rule 56a. Issues related to the interpretation of Rule 18c were explained by Tindall [6] and in previous Judicial Opinions
[9, 10]. ere is no time limit set in the ICNP for proposing a neotype strain; the course of action to be taken depends on the
particular nature of the problem.
e Judicial Commission notes that the original description of Khunthongpan et al. [13] shows divergence between strain C2361T
and the type strain of Enterobacter cloacae subsp. cloacae in the utilization of several carbohydrates indicating that the two strains
diverged when the original analysis was performed.
It should also be noted that the GenBank/EMBL/DDBJ entry HQ888848 has been updated by the submitter to a version 2 in
February 2016, immediately aer the publication of the request for an opinion by Kämpfer et al. [12] in January 2016. e new
version diers signicantly from the original one but also from CP001918. e reason for the new version is not provided and
we do not know if it represents resequencing of the same or another strain or just a reassembly of the original reads. It is unclear
based on the 16S rRNA gene sequences alone whether the deposited sequences (HQ888848.1 and HQ888848.2) are accurate
reections of the 16S rRNA gene sequence of the material investigated in the authors’ laboratory [13] or whether both have errors
in them. n search in NCBI with HQ888848.2 shows 100 % identity to an uncultured bacterium (KR612021) documenting
that an organism belonging to Enterobacter siamensis may exist.
e request for an opinion by Kämpfer et al. [12] would be more informative if the authors had checked the obtained strain
C2361T for the presence of several phenotypic features that dierentiate Enterobacter siamensis and related Enterobacter species
as reported by Khunthongpan et al. [13]. For example, tests for the ability to utilize gentiobiose, lyxose and turanose would be
highly relevant. Negative results would serve as additional evidence for the fact that the original strain on which the description
of the species Enterobacter siamensis is based has been misplaced.
e description section of Enterobacter siamensis does not list a 16S rRNA gene sequence, hence sequence information is not
an integral part of the taxon description, although the gene was analysed. e possibility that only the 16S rRNA gene sequence
reported by Khunthongpan et al. [13] was wrong cannot be excluded, albeit the replacement of HQ888848.1 by HQ888848.2 is
somewhat dubious.
If the type strain of the species Enterobacter siamensis, which formed the basis for the species description in the original publica-
tion, had never been deposited in an established culture collection, the name would not meet the requirements for valid publication
given in Rule 30(3b) in conjunction with Rule 27. e name Enterobacter siamensis Khunthongpan et al. 2014, therefore, would
not be validly published although it was included in a Validation List [9, 10].
e distinct 16S rRNA gene sequences obtained from allegedly the same strain may also point to a mixed culture. In case of a
taxon description being based on a mixed culture the name Enterobacter siamensis may be rejected as a nomen confusum according
to Rule 56a(3). e data provided by Kämpfer et al. [12] are not sucient to rule out this possibility either. Moreover, Kämpfer
et al. [12] did not mention accession numbers of the sequences they obtained, which makes reproducing their sequence analysis
unnecessarily dicult.
e Judicial Commission concludes that the only way to establish whether the currently available deposits of the designated
type strain reect the properties reported by Khunthongpan et al. [12] is to carry out further biochemical/physiological tests.
It is not currently possible to determine what the strains currently available represent. e Judicial Commission therefore does
not place the name Enterobacter siamensis on the list of rejected names at this time. Denying the request was favoured by 11
commissioners; one commissioner abstained.
OPINION 115
Kimura and colleagues [15] request placing the name Moorella thermoautotrophica (Wiegel et al. 1981) Collins et al. 1994 on
the list of rejected names in accordance with Rule 56a as the type strain deposits in the public collections appeared to be mixed
cultures. e Judicial Commission does not agree with the interpretation of Rule 18c by Kimura et al. [15]. Rule 18c is not directly
involved in the rejection of names, which is regulated by Rule 56a. e 2- year period stipulated in Rule 18c is the period between
the proposal of a neotype strain and its establishment. Issues related to the interpretation Rule 18c were explained by Tindall [6]
and in previous Judicial Opinions [9, 10]. However, the status of Moorella thermoautotrophica (Wiegel et al. 1981) Collins et al.
1994] needs to be claried.
While Kimura et al. [15] do not request the rejection of the name Clostridium thermoautotrophicum Wiegel et al. 1981 it also
needs to be considered here because it is the basonym (and thus a homotypic synonym) of the other name. e description of
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Arahal etal., Int. J. Syst. Evol. Microbiol. 2022;72:005481
Clostridium thermoautotrophicum Wiegel et al. 1981 [16] is based on the strain designated as JW 701/3T while the description of
Moorella thermoautotrophica (Wiegel et al. 1981) Collins et al. 1994 [17] is based on its alleged deposit DSM 1974T.
Clostridium thermoautotrophicum Wiegel et al. 1981 and Moorella thermoautotrophica (Wiegel et al. 1981) Collins et al. 1994
were described without determining a 16S rRNA gene sequence as these descriptions were completed prior to the wide use of
the 16S rRNA gene analysis approach [16, 17]. Only DNA–DNA hybridization (DDH) was performed with the type strain JW
701/3T at that time, with 48.5 % similarity to the most closely related type strain, Clostridium thermoaceticum Fontaine et al. 1942
DSM 521T. is value may or may not be accurate, as the traditional DDH method is characterized by substantial experimental
noise. e diagnostic trait of Moorella thermoautotrophica apparently is its distinctive ability to degrade methanol and, for some
strains, arabinose, and growth at 70 °C.
e 16S rRNA gene sequence of the Moorella thermoautotrophica type strain DSM 1974
T
was determined later, by dierent
authors, and is available in GenBank (accession number L09168). Collins et al. [17] showed that Clostridium thermoaceticum
and Clostridium thermoautotrophicum aliated closely and proposed their classication in the new genus Moorella Collins et al.
1994 with Moorella thermoacetica as type species.
However, it is clear that the cultures available in the public collections, which were used to determine this 16S rRNA gene
sequence, are not pure because the subsequent cultivation and sequencing of several strains derived from the culture collections
DSMZ and ATCC (DSM 1974T=ATCC 33924T) by Kimura et al. [15] has revealed the coexistence of four distinct operational
taxonomic units (OTUs), representing two dierent species. ree of the OTUs matched the sequences of Moorella thermo-
autotrophica (accession number L09168) and Moorella thermoacetica that share 99.6 % gene sequence identity; and one OTU
aliated with Moorella humiferrea strain 64T [18] with 99.2 % sequence identity. e conclusion of Kimura et al. [15] is that
both cultures shared the same mixed species and that they were probably already mixed from the source. As indicated by the
authors, ATCC 33924T derived from DSM 1974T, and therefore the mixed culture was generated either before or directly aer
the deposit at DSMZ.
Kimura and colleagues used the match against the available GenBank 16S rRNA gene sequence as evidence that no recovered
strain from the culture collections represents the originally described type strain of Moorella thermoautotrophica because no 100 %
match was found (instead, a 100 % match to Moorella thermoacetica was found among the four OTU sequences). However, the
0.4 % dierence between both sequences of Moorella thermoautotrophica and Moorella thermoacetica could be just due to minor
sequencing errors. e sequence AB572912 contains two ‘insertions’ more than L09168 at positions 1041 and 1472 and both
dier just in one G/C in position 105. erefore, practically both sequences can be taken as nearly identical. However, Collins
and colleagues [17] used strain DSM 1974T for PCR amplication and sequencing, which was probably already a mixed culture,
and this could be consistent with a 16S rRNA not perfectly matching any other sequence.
On the other hand, one of the OTUs of the mixed cultures aliated with Moorella humiferrea Nepomnyashchaya et al. 2012 [18]
with 99.2 % sequence identity. is species’ phenotype matches the original description of Clostridium thermoautotrophicum
Wiegel et al. 1981 to a great extent, especially the growth at 70 °C, and could support the DDH results obtained by Wiegel
and colleagues [16]. e non- matching features such as the use of glucose, maltose, and methanol could be either part of the
intraspecic diversity of the species or support the conclusion that the culture of JW 701/3T was already a mixed culture when
deposited as DSM 1974T.
Redl et al. [19] re- isolated two dierent strains from cultures of DSM 1974T, which were deposited as DSM 103284 and DSM
103132. Both strains were genomically studied (with the genome accession numbers CP017019 and CP017237) and closely ali-
ated with all other members of the species Moorella thermoacetica. Conspicuously they did not retrieve any strain corresponding
to OTU- 4, i.e. the second clone aliated with Moorella humiferrea, which was obtained from both DSM 1974
T
and ATCC 33924
T
cultures by Kimura et al. [15]. Redl et al. [19] reached the conclusion that it is impossible to determine whether the original strain
was already a mixture of dierent organisms or was mixed (contaminated) aer its deposit. ese authors recommended the
recognition of Moorella thermoautotrophica (Wiegel et al. 1981) Collins et al. 1994 as a later heterotypic synonym of Moorella
thermoacetica (Fontaine et al. 1942) Collins et al. 1994. However, as Moorella thermoautotrophica (Wiegel et al. 1981) Collins et
al. 1994 is based on DSM 1974T instead of JW 701/3T, it is not of primary importance whether JW 701/3T was already a mixed
culture prior to its deposit at DSMZ.
e fact that Redl et al. [19] did not recover the OTU- 4 [15] led to their conclusions that DSM 1974T was a mixed culture of two
dierent strains of Moorella thermoacetica. However, a larger eort may be needed to retrieve the OTU- 4 representatives, which
had been readily isolated previously from the deposits of both collections DSMZ and ATCC. ere is a need to evaluate the
phenotype of isolates corresponding to OTU- 4 and to compare it with that of Moorella humiferrea Nepomnyashchaya et al. 2012
[18]. However, this would not aect that status of Moorella thermoautotrophica (Wiegel et al. 1981) Collins et al. 1994 because it
is likely that it is based on a mixed culture, DSM 1974T, apparently containing distinct species of Moorella with a validly published
name. If the phenotype of OTU- 4 matches the phenotype described for Clostridium thermoautotrophicum Wiegel et al. 1981,
then JW 701/3T may have been pure, but this does not remove the problems associated with its deposits.
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Arahal etal., Int. J. Syst. Evol. Microbiol. 2022;72:005481
To deny the request due to insucient evidence was favoured by four commissioners. Eight commissioners chose the following
interpretation: Irrespective of whether or not strain JW 701/3
T
was already a mixed culture, Moorella thermoautotrophica ] (Wiegel
et al. 1981) Collins et al. 1994 was based on DSM 1974T. Its description does not even mention JW 701/3T. It is very likely that
DSM 1974
T
is a mixed culture. Moreover, all of its component species appear to correspond to other Moorella species with a validly
published name. For this reason, the species is considered as a nomen confusum according to Rule 56 a(3) and the name is placed
on the list of rejected names. One needs to take into account that this implicitly also rejects Clostridium thermoautotrophicum
Wiegel et al. 1981 (see Opinion 106 [10]) although it is based on JW 701/3
T
(and only mentions DSM 1974
T
as a deposit). is does
not matter, however, since the name is not in use and since it otherwise would conict with Moorella species that have a validly
published name. It was also taken into account that Moorella thermoautotrophica is most likely composed of a mixture of Moorella
species that already have a validly published name and thus would each compete with Moorella thermoautotrophica for priority.
OPINION 116
Rule 8 of the ICNP [5] stipulates that names of classes are formed by adding the ending - ia to the stem of the name of the type
genus of the type order of the class and that names of subclasses are formed by adding the ending - idae to the stem of the name of
the type genus of the type order of the subclass. When this rule was introduced into the ICNP, it was not explicitly marked as not
being retroactive, which according to Rule 2 implies that Rule 8 is retroactive. Rule 8 ensures that names of classes are formed in
a uniform manner by using a common scheme. However, the current wording of Rule 8 also has the consequence that a compara-
tively large number of names of classes, including widely used and well known names, and some names of subclasses, become
illegitimate [20, 21]. Oren et al. [20] requested the Judicial Commission to reconsider whether Rule 8 should be retroactive.
An alternative proposal was made for rephrasing Rule 8 to ensure that the scheme only applies to names of classes and subclasses
validly published aer 31 December 2011 [21]. At the time of consideration of this request, the Tindall proposal [21] was due
to be debated by the International Committee on Systematics of Prokaryotes (ICSP), and an online platform was established for
discussing this and other proposals to modify the ICNP [22, 23]. While the Judicial Commission was able to contribute to this
debate, the matter will be decided by the voting members of the ICSP and cannot be treated in this Judicial Opinion. In fact, the
question of retroactivity of Rule 8 is an objective conict between the goal of retaining well established taxon names and the goal
of establishing a uniform naming scheme from which the category of classes and subclasses and their nomenclatural type can
unambiguously be inferred.
However, it appears to be helpful to determine the exact consequences of either version of Rule 8 and, in particular, it seems to
be necessary to determine how to deal with deviations from its wording. Since Rule 8 only describes a special case of how all
names of taxa of rank higher than genus are formed, generally applicable guidelines are needed.
NAMES OF CLASSES VALIDLY PUBLISHED AFTER 2011
e Judicial Commission realized that there are a number of names of a rank higher than genus that were formed in an unexpected
way and are not aected by the retroactivity of Rule 8. It must be examined under which conditions orthographical corrections
can be made, and the status of these names needs to be claried to obtain a uniform and unambiguous treatment of names that
deviate from the expected scheme. For instance, there are names of classes that were validly published under the ICNP aer 31
December 2011 [24–30] but do not correspond at all or do not entirely correspond to the schema outlined in Rule 8 (Table1).
Even if Rule 8 was not treated as retroactive, these names would need to be reconsidered.
Table 1. Names of classes validly published under the ICNP after 2011 and not at all or not entirely conforming to the schema enforced by Rule 8
The actual stem is the stem of the name of the type genus of the type order of the class. The implicit ending is the ending derived from the name and
the stem. The intended ending is the ending of the name explicitly provided in its etymology in the eective publication.
Taxon name Actual stem Implicit ending Intended ending Orthographical correction
Abditibacteria Tah on et al. 2018 Abditibacteri- (- ales, - um)-a -ia Abditibacteriia corrig. Tahon et al. 2018]
Endomicrobia Zheng et al. 2018 Endomicrobi- (- ales, - um)-a -ia Endomicrobiia corrig. Zheng et al. 2018
Hydrogenophilalia Boden et al. 2017 Hydrogenophil- (- ales, - us)-alia -alia None, illegitimate name
Kiritimatiellae Spring et al. 2017 Kiritimatiell- (- ales, - a)-ae Not given None, illegitimate name
Longimicrobia Pas cual et al. 2016 Longimicrobi- (- ales, -um)-a -ia Longimicrobiia corrig. Pascual et al. 2016
Polyangia Wai te et al. 2020 Polyangi- (- ales, - um)-a -ia Polyangiia corrig. Waite et al. 2020
Terrimicrobia García- López et al. 2020 Terrimicrobi- (- ales, - um)-a -ia Terrimicrobiia corrig. García- López et al. 2020
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e authors of most of the deviating names of classes actually intended the - ia ending in accordance with Rule 8 and just accidentally
dropped one letter - i- from a pair of adjacent letters - i-. e collision of two letters - i- occurs whenever - i- is the last letter of the stem,
as - i- is also the rst letter of the standardized ending. e Judicial Commission opines that the magnitude of the deviation of these
names from the accurate spelling is within the range of an orthographical correction [20]. While there is no ambiguity regarding the
ending - ia, errors with respect to the stem of a name may oen be made. Such cases should be treated with leniency.
e Judicial Commission thus does not interpret these names as illegitimate. Moreover, in Judicial Opinion 105 the commission
reiterated that incorrect Latin or incorrect Latinization does not render a name illegitimate, that a name based on incorrect Latin or
incorrect Latinization can be corrected but needs not be corrected by the Judicial Commission, and that an orthographical correction
could not rescue an illegitimate name [10].
However, it should be noted that the kind of orthographical error made here is not akin to an incorrect spelling of a Latin name
or an incorrect Latinization, which may be apparent only to experts of languages such as Latin or Greek. Rather, regularly formed
names of classes, much like all regularly formed names of taxa of a rank higher than genus, are derived from other taxon names; they
are not directly derived from Latin or Latinized words. e kind of derivation of the names of taxa higher than the rank of genus is
specied exactly by the ICNP [5]. If several names of higher taxa are supposed to be derived from the stem of the same genus name
but at least one of these stems was derived incorrectly, this causes an inconsistency in nomenclature that is independent of the actual
orthographical correctness of any of those names.
In a Linnaean system the aliation of a subspecies to its species is apparent from the trinomial name of the subspecies. Likewise, the
aliation of a species to its genus is apparent from the binomial name of the species. is does not normally hold for the relationships
between taxa of higher rank. e only exception is the relationship between the name of a higher taxon and the name of its nomen-
clatural type (or the name of the nomenclatural type of its nomenclatural type), from which it is derived. is kind of relationship
should be as unambiguous as the subspecies- species relationship and the species- genus relationship. While the etymology of names
of genera, species and subspecies may or may not provide important information for users of these names, the etymology of names of
taxa of higher rank does. While belated orthographical corrections of taxon names may cause confusion, names of higher taxa derived
from names of genera in an irregular manner may also be confusing, particularly because they can obscure the relationships between
names and can cause inconsistencies in nomenclature. Moreover, they could serve as inaccurate templates for proposing new names
of higher taxa and thus further increase confusion.
is argues for correcting names of classes (and of other taxa of a rank higher than genus) whenever possible and necessary.
Accordingly orthographically corrected names of classes are provided in Table1. Eleven commissioners voted for conducting
these corrections, one commissioner abstained. e status, authors and dates of valid publication of these names are not aected
by the orthographical corrections.
Adjacent - i- letters may be regarded as unpleasant but they already occur in validly published names of classes. In fact,
they are an inevitable consequence of the usage of the ending - ia and the composition of the stem of certain genus names.
Adjacent - i- letters also occur in classical Latin and are frequently encountered in epithets formed from personal names as
genitive nouns as indicated in Appendix 9D of the ICNP [5]. Furthermore, the presence of an additional - i- letter may resolve
ambiguity regarding the derivation of the name of a family, suborder, order, subclass or class.
For instance, the hypothetical genus with the name ‘Pasteuribacter’ would yield ‘Pasteuribacteraceae’, ‘ Pasteuribacterales’
and ‘Pasteuribacteria’ if used as the nomenclatural type of a family, order, or class, whereas the hypothetical genus name
‘Pasteuribacterium’ would yield ‘Pasteuribacteriaceae’, ‘ Pasteuribacteriales’ and ‘Pasteuribacteriia’. Deriving the names
‘Pasteuribacteriales’ and ‘Pasteuribacteria’ from ‘Pasteuribacterium’ would yield an inconsistency irrespective of the ortho-
graphical correctness of ‘Pasteuribacterium’, as ‘Pasteuribacteriales’ implies Pasteuribacteri- as stem while ‘Pasteuribacteria’
implies Pasteuribacter- as stem.
In the case of Hydrogenophilalia Boden et al. 2017 the intended ending, as provided in the etymology section of the name in
the eective publication, and the actual ending are - alia, contravening Rule 8. is name must be interpreted as illegitimate.
In the case of Kiritimatiellae Spring et al. 2017 the intended ending is not explicitly given in the eective publication but the
actual ending is - ae, contravening Rule 8. is name must also be interpreted as illegitimate.
According to Rule 51a, illegitimate names may not be used [5]. Authors are encouraged to provide replacement names, which
could refer to the original description and attribute the name to the original authors. However, it would not be possible to retain
the date of valid publication.
NAMES OF CLASSES AND SUBCLASSES VALIDLY PUBLISHED BEFORE 2012
In light of the reasoning given above, names of classes that dier from the expected name only by the replacement of a required pair
of adjacent - i- letters by a single - i- letter should be orthographically corrected. e Judicial Commission realized that there are names
of classes that were validly published before or on 31 December 2011 and which were potentially formed in the same way [31–37].
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at is, it may be that these names were also intended to apply the naming scheme that comprises the stem of the type genus of the
type order of the class followed by the ending - ia but the authors inadvertently used - i- in place of - ii-. ere are also some names of
subclasses that may be aected by the confusion of - ii- and - i- [38].
If Rule 8 was treated as retroactive, these names would either be illegitimate or require an orthographical correction. If Rule 8 was
not treated as retroactive, these names would remain confusing because their composition closely resembled the one expected from
names validly published aer 31 December 2011 but did not fully meet the expectations. It is thus advisable to also clarify the status
of these names. e cases are listed in Table2.
Screening the literature reveals that in none of these cases the authors indicated their intention to use the - ia ending for the
name of a class. In one instance, the intended ending - a was provided. In the majority of the cases the authors used phrasings
like this to explain the etymology of the name:
“M.L. fem. pl. n. Halobacteriales type order of the class; dropping the ending to denote a class; M.L. fem. pl. n. Halobacteria the
class of Halobacteriales.”
While dropping - les would yield Halobacteria, dropping the real ending from Halobacteriales yields Halobacteri, which implies that the
authors [31] intended to use - a as the ending of the name of a class. is is in accordance with, e.g., the formation of the class name
ermoplasmata from ermoplasmatales in the same volume of Bergey’s manual [39]. ere is thus no indication of an intention
to use the ending - ia to form the name of the class. We are not dealing with Halobacter +ia but w ith Halobacteri +a. e Judicial
Commission thus sees no basis for conducting orthographical corrections of such names listed in Table2. e fate of these names
has to be determined by the decision of the ICSP on the retroactivity of Rule 8; the names will either remain illegitimate or need not
orthographically be corrected.
As for the names of subclasses listed in Table2, Actinobacteridae was intended to use the ending - idae but a genus name Actinobacter
or Actinobacterium from which it could be derived was not validly published and legitimate under the ICNP when the name of the
subclass was proposed [38]. e name Actinobacteridae cannot be orthographically corrected and needs to be treated depending on
the future wording of Rule 8. e other names of subclasses listed in Table2 can be corrected, however. Eleven commissioners voted
for conducting these corrections, one commissioner abstained.
e Judicial Commission noted that whether Rule 8 should be retroactive regarding names of classes and whether it should
be retroactive regarding names of subclasses are actually two distinct questions. e retroactivity of Rule 8 has certainly
more impact in practice regarding names of classes.
ADDENDUM: NAMES OF SUBORDERS AND FAMILIES WITH SIMILAR PROBLEMS
In contrast to Rule 8, the retroactivity of the rules which govern the formation of names of taxa above the rank of genus and
below the rank of subclass has not been called into question. Nevertheless, the Judicial Commission noted that there are cases
Table 2. Names of classes and subclasses validly published under the ICNP before 2011 and not entirely conforming to the schema enforced by Rule
8 but potentially intended to do so
The stem given is the stem of the name of the type genus of the type order of the class or subclass. The intended ending is the ending of the name
provided in the etymology of the name in the eective publication. The asterisks highlight cases in which the intended ending is not explicitly given
but can be inferred.
Taxon name Actual stem Implicit ending Intended ending Orthographical correction
Acidimicrobidae Stackebrandt et al. 1997 Acidimicrobi- (- ales, - um)-dae -idae Acidimicrobiidae corrig.
Stackebrandt et al. 1997
Actinobacteridae Stackebrandt et al. 1997 – – -idae –
Clostridia Rainey 2010 Clostridi- (- ales, - um)-a -a* –
Coriobacteridae Stackebrandt et al. 1997 Coriobacteri- (- ales, - um)-dae -idae Cor iobacteriidae corrig.
Stackebrandt et al. 1997
Elusimicrobia Geissinger et al. 2010 Elusimicrobi- (- ales, - um)-a Not given –
Halobacteria Grant et al. 2002 Halobacteri- (- ales, - um)-a -a* –
Ignavibacteria Iino et al. 2010 Ignavibacteri- (- ales, - um)-a -a –
Methanobacteria Boone 2002 Methanobacteri- (- ales, - um)-a -a* –
ermodesulfobacteria Hatchikian et al. 2002 ermodesulfobacteri- (- ales, - um)-a -a* –
ermomicrobia Garrity and Holt 2002 ermomicrobi- (- ales, - um)-a -a* –
9
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in which names of suborders or families were not entirely formed from the stem of the name of type genus [38, 40–50]. It makes
sense to consider these names here to distinguish situations in which a name has to be treated as illegitimate from cases in which
a name needs to be orthographically corrected in a manner consistent with the treatment of the names of classes and subclasses
given above.
Among the names listed in Table3, the name Enterobacteriaceae is not formed from the name of its nomenclatural type, which is
Escherichia Castellani and Chalmers 1919 (Approved Lists 1980). However, the name Enterobacteriaceae Rahn 1937 (Approved
Lists 1980) was sanctioned by Judicial Opinion 15 [51] and can be based on Rule 21b of the ICNP.
In the case of suborders the typical mistake made in the literature is the usage of - i- instead of - ii- as in the case of classes and
subclasses as discussed above. ese names can easily be orthographically corrected.
Names of families are sometimes aected by the usage of the wrong stem. is is unambiguous if the stem to be used is the stem
of a Latin word such as balneatrix or vorax, which is found in Latin dictionaries together with its genitive. e names validly
published and legitimate under the ICNP and ending in - voracaceae or - voracales can serve as precedents [52]. As for the treatment
of the genitive of Latinized words of Greek origin [53, 54], those ending in - ma are unambiguous, including plasma, genitive
plasmatis (Greek πλσα, genitive πλσατο), and soma, genitive somatis (Greek σα, genitive σατο). Again, there are a
variety of names validly published and legitimate under the ICNP that can serve as precedents [52].
Words of Greek origin that end in -is are more dicult in principle although a traditional treatment in taxonomic nomenclature
may already be established [54]. e validly published and legitimate names Methylocystaceae Bowman 2006, Nannocystaceae
Reichenbach 2006, Nannocystales (Reichenbach 2007) Waite et al. 2020 and Nannocystineae Reichenbach 2007 [30, 45, 55]
indicate that the genitive of cystis is considered to be cystis under the ICNP (Greek κστι, genitive κστεω or κστιδο), which
is in accordance with the treatment under the International Code of Nomenclature for algae, fungi, and plants (ICN), although
cystidis would also have been possible [54].
e genitive of opsis would be opsis according to classical tradition (Greek ψι, genitive ψεω). Botanical tradition is dierent,
however, as names of algal families validly published under the botanical code use opsidis instead [54]. Names of Cyanobacteria
validly published under the ICN are now recognized as also being validly published under the ICNP [56]. is yields at least the
Table 3. Names of families and suborders validly published under the ICNP and regarded as legitimate (unless indicate otherwise) but not correctly
formed from the name of the nomenclatural type
For each category the ending as stipulated by the ICNP is given. The stem given is the stem of the name of the type genus.
Taxon name Category Ac tual stem Orthographical correction
Balneatrichaceae Krishnan et al. 2019 Family (- aceae)Ba lneatric - (balneatrix, genitive balneatricis)Balneatricaceae corrig. Krishnan et al. 2019
Branhamaceae Catlin 1991 Family (- aceae)Branhamell- (- a) None, illegitimate name [Rule 51b(1)]
Catalimonadaceae Choi et al. 2013 Family (- aceae)Catalinimonad- (monas, genitive monadis)Catalinimonadaceae corrig. Choi et al. 2013
Corynebacterineae Stackebrandt et al. 1997 Suborder (- ineae)Corynebacteri- (- um)Corynebacteriineae corrig. Stackebrandt et
al. 1997
Enterobacteriaceae Rahn 1937 (Approved Lists
1980)
Family (- aceae) – None, legitimate name (known exception)
Ferroplasmaceae Golyshina et al. 2000 Family (- aceae)Ferroplasmat- (plasma, genitive plasmatis)Ferroplasmataceae corrig. Golyshina et al. 2000
Frankineae Stackebrandt et al. 1997 Suborder (- ineae)Franki- (- a)Frankiineae corrig. Stackebrandt et al. 1997
Halobacteriovoraceae Koval et al. 2015 Family (- aceae)Halobacteriovorac- (vorax, genitive vorac is)Halobacteriovoracaceae corrig. Koval et al. 2015
Nocardiopsaceae Rainey et al. 1996 Family (- aceae)Nocardiopsid- (opsis, genitive opsidis) or
Nocardiops- (opsis, genitive opsis)
Nocardiopsidaceae corrig. Rainey et al. 1996
Phaselicystidaceae Garcia et al. 2009 Family (- aceae)Phaselicystid- (cystis, genitive cystidis) or
Phaselicyst- (cystis, genitive cystis)
Phaselicystaceae corrig. Garcia et al. 2009
Propionibacterineae Rainey et al. 1997 Suborder (- ineae)Propionibacteri- (- um)Propionibacteriineae corrig. Rainey et al. 1997
Proteinivoraceae Kevbrin et al. 2014 Family (- aceae)P roteinivorac- (vorax, genitive voraci s)Proteinivoracaceae corrig. Kevbrin et al. 2014
Pseudonocardineae Stackebrandt et al. 1997 Suborder (- ineae)Pseudonocardi- (- a)Pseudonocardiineae corrig. Stackebrandt et
al. 1997
Spirosomaceae Larkin and Borrall 1978
(Approved Lists 1980)
Family (- aceae)Spirosomat- (soma, genitive somatis)Spirosomataceae corrig. Larkin and Borrall
1978 (Approved Lists 1980)
Streptosporang ineae Ward- Rainey et al. 1997 Suborder (- ineae)Streptosporangi- (- um)Streptosporangiineae corrig . Ward- Rainey et
al. 1997
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following names of Cyanobacteria based on opsidis that need to be recognized: Chlorogloeopsidaceae Mitra and Pandey 1967,
Chroococcidiopsidaceae Komárek et al. 2014 and Chroococcidiopsidales Komárek et al. 2014 [57, 58]. Given the long- standing
approach in botany [54], this would call for using these these names as precedents and to correct names ending in - opsaceae
accordingly. On the other hand, regulations such as Rule 57a would call for - opsaceae rather than - opsidaceae, if one could argue
that botanical tradition is of minor importance for determining the correctness of a Latin or Latinized name.
Nine commissioners voted for conducting the correction of Nocardiopsaceae to Nocardiopsidaceae, two commissioners opposed,
and one commissioner abstained. Eleven commissioners voted for conducting the other corrections listed in Table3 while one
commissioner abstained.
OPINION 117
A Request for an Opinion by Oren and Boden [59] asked to designate ‘Methylothermus subterraneus’ Hirayama et al. 2011 [60] as
the type species of the genus ‘Methylothermus’ Tsubota et al. 2005 in place of ‘Methylothermus thermalis’ Tsubota et al. 2005 [61].
e perceived problem with ‘Methylothermus thermalis’ Tsubota et al. 2005 is that the type strain was, at the time of publication
of the name, not deposited in two distinct culture collections in two distinct countries from which it would be available.
e Judicial Commission agrees that one of the type- strain deposits (IPOD FERM P- 19714
T
) is a patent deposit and, accordingly,
the name ‘Methylothermus thermalis’ Tsubota et al. 2005 does not meet the requirements given in Rule 30(4) of the ICNP [5].
Contrary to the Request for an Opinion, the Judicial Commission concludes from this observation that the major problem related
to the species name ‘Methylothermus thermalis’ Tsubota et al. 2005 is that it is not validly published, rather than being validly
published and illegitimate. is holds because the name does not meet the requirements for valid publication given in Rule 27(3),
which refers to Rule 30 for names of species. A similar point was made in previous Judicial Opinions [10, 62].
Accordingly, the major problem associated with the genus name ‘Methylothermus’ Tsubota et al. 2005 is not that it contravenes
Rule 20a but that it does not meet the requirement given in Rule 27 Note 2. Accordingly, ‘Methylothermus’ Tsubota et al. 2005 is not
validly published, rather than being validly published and illegitimate. In a similar vein, ‘Methylothermaceae’ Hirayama et al. 2014
[63] is not validly published because it is based on ‘Methylothermus’ Tsubota et al. 2005 as type genus. Finally, ‘Methylothermus
subterraneus’ Hirayama et al. 2011 is not validly published either as it does not comply with the conditions stated in Rule 27 Note 2.
e Judicial Commission thus agrees with the interpretation of the situation by Tindall [64] and the subsequent actions conducted
by that author. ese yielded the valid publication of the names Methylothermus Hirayama et al. 2019, Methylothermus subter-
raneus Hirayama et al. 2019 and Methylothermaceae Hirayama et al. 2019. (Note that Tindall [64] assigned Hirayama et al. as
the authority of the names based on his reuse of the descriptions previously given by these authors [60, 63].) No further action
is required, hence the request is denied because the observed problem was solved in the meantime. is solution was favoured
by all 12 commissioners.
OPINION 118
A Request for an Opinion by Oren [65] called for the orthographical correction of the name Flaviaesturariibacter Kang et al.
2015 to Flavaestuariibacter. e eective publication of the name [66] used the spelling Flaviaesturariibacter throughout but
gave the following etymology:
“Flaviaesturariibacter ( Fla. vi. aes. tu. a. ri. i. bac′ter. L. adj. avus yellow; L. n. aestuarium estuary; N.L. masc. n. bacter a rod; N.L.
masc. n. Flaviaestuariibacter a yellow, rod- shaped bacterium from an estuary).”
is indicates that the intended spelling was Flaviaestuariibacter derived from the Latin neuter noun aestuarium, which can, in
contrast to aesturarium, be found in dictionaries, as stated by Oren [65]. However, the Judicial Commission could not conrm
the claim in the Request for an Opinion [65] that the Notication List that included the name [67] already corrected the spelling
to Flaviaestuariibacter; instead it also used Flaviaesturariibacter. e Judicial Commissions agrees with Oren [65] that Appendix
9 section A(1c) of the ICNP indicates that in compound nouns a connecting vowel must be dropped when the following word
element starts with a vowel [5] and that the orthographically correct spelling is Flavaestuariibacter.
However, the Judicial Commission emphasized in Judicial Opinion 105 that a name does not contravene the ICNP just because
of an incorrect orthography and that an orthographical correction cannot make an illegitimate name legitimate [10]. e Judicial
Commission can conduct orthographical corrections but is not normally obliged to do so [10]. In contrast to other cases of
orthographically incorrect names, the situation regarding Flaviaesturariibacter is special because this spelling may have been
used inadvertently by the authors [66].
us there are three options: to not conduct any orthographical correction, to correct the name to Flaviaestuariibacter as probably
originally intended by the authors, and to correct the name to Flavaestuariibacter as proposed in the Request for an Opinion
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[65]. An orthographical correction would aect one genus name and three species names [66, 68, 69]. While the commissioners
unanimously favoured a correction of the name, four preferred Flavaestuariibacter while eight preferred Flaviaestuariibacter.
e Judicial Commission noted another situation in which a name was probably inadvertently printed incorrectly, namely
regarding the genus Fredinandcohnia [70, 71]. e etymology section in the eective publication gives the following information:
“Ferdinandcohnia [N.L. fem. n. Ferdinandcohnia, named aer German Biologist Prof. Ferdinand Cohn (1828–1898), one of the
founders of modern bacteriology and microbiology, for his studies of algae, bacteria and fungi].”
e spelling Fredinandcohnia may be regarded as doing a disservice to the late Ferdinand Cohn [72]. It may also be unpleasant
particularly for speakers of the German language because there does not appear to be any evidence for the usage of the given name
Fredinand at all, as opposed to the well- known Ferdinand. An orthographical correction to Ferdinandcohnia would aect one genus
name and four species names [70, 71]. Eleven commissioners voted for conducting this correction, one commissioner abstained.
An inadvertent misprint may also aect the name Hydrogeniiclostidium [73, 74]. A genus name ‘Clostidium’ from which this name
could be derived is not known, and the etymology of the name within the eective publication states:
“Hydrogeniiclostidium ( Hy. dro. ge. ni. i. clos. tri′ di. um. N.L. neut. n. hydrogenium hydrogen; N.L. neut. n. Clostridium a bacterial
genus; N.L. neut. n. Hydrogeniiclostridium a hydrogen- producing Clostidium) .”
Accordingly, occurrences of the most likely intended spelling Hydrogeniiclostridium, derived from the well- known genus name
Clostridium, are intermixed with the probable misprint. An orthographical correction to Hydrogeniiclostridium would aect one
genus name and one species name [73, 74]. Eleven commissioners opted for conducting this correction, with one abstention.
OPINION 119
Rule 8 of the ICNP regulates how names of classes have to be formed [5]. It was proposed to modify Rule 8 to make it non-
retroactive, i.e. to be only applicable to names of classes validly published aer 31 December 2011 [21]. is proposal is currently
under consideration by the ICSP [22, 23].
Rule 8 stipulates that names of classes are formed by adding the ending - ia to the stem of the name of the type genus of the type
order of the class [5]. A variety of validly published names of classes deviate from this scheme, mostly by using endings other
than - ia [20]. ese names are illegitimate as long as Rule 8 remains retroactive. According to Rule 2, all rules not explicitly
marked otherwise are retroactive [5].
Some names of classes validly published prior to 1 January 2012 are also illegitimate because they lack a nomenclatural type. Rule
22 indicates that the Judicial Commission can assign a nomenclatural type to a taxon above the rank of order if a type was not
originally assigned [5]. Oren [75] asked the Judicial Commission to establish Actinomycetales Buchanan 1917 (Approved Lists
1980) [4, 76] as the type order of the widely used but illegitimate name Actinobacteria Stackebrandt et al. 1997. is Request
for an Opinion noted that Actinomycetes Krassilnikov 1949 (Approved Lists 1980) [4, 77] is a validly published and illegitimate
synonym of Actinobacteria Stackebrandt et al. 1997. While the type order of Actinomycetes Krassilnikov 1949 (Approved Lists
1980) could also be set to Actinomycetales Buchanan 1917] (Approved Lists 1980), Oren [75] argued for repairing only Actino-
bacteria Stackebrandt et al. 1997 because it is the better known name and because Actinomycetes Krassilnikov 1949 (Approved
Lists 1980) would obtain priority if a type order was established for both names.
e situation is further complicated by the valid publication of the name Actinomycetia Salam et al. 2020 [78]. is name is
currently legitimate but if Actinomycetes Krassilnikov 1949 (Approved Lists 1980) or Actinobacteria Stackebrandt et al. 1997
were also made legitimate, Actinomycetia Salam et al. 2020 would become a later homotypic synonym. Since the decision on the
retroactivity of Rule 8 is pending, a solution is needed that braces for all possible outcomes of the ballot of the ICSP. It must also
be taken into consideration that a proposal is under debate to change the nomenclatural type of classes from an order to the type
genus of that order [79]. If accepted, this proposal would not change the spelling of class names, however, and a proposal was
also made during the public debate [22] to manage the transition, if any, from an order to a genus as nomenclatural type with
ease, even if the change was retroactive. is issue thus does not further complicate the matter treated in this Judicial Opinion.
e name Actinomycetes Krassilnikov 1949 (Approved Lists 1980) is formed from the stem of the type genus of Actinomycetales
Buchanan 1917 (Approved Lists 1980), which is Actinomyces Harz 1877 (Approved Lists 1980) [4, 80]. e name is formed
as Actinomycet +es and contravenes Rule 8 by using the wrong ending. e authors of Actinobacteria Stackebrandt et al. 1997
deliberately used the ending - ia (Actinobacter+ia) but did not derive the name from a genus name. Neither the genus name
Actinobacter nor the name Actinobacterium (which would correctly yield the class name Actinobacteriia) were validly published
when Actinobacteria Stackebrandt et al. 1997 was proposed.
us if Rule 8 remained retroactive, neither Actinomycetes Krassilnikov 1949 (Approved Lists 1980) nor Actinobacteria Stack-
ebrandt et al. 1997 could become legitimate by establishing Actinomycetales Buchanan 1917 (Approved Lists 1980) as their
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nomenclatural type. e correct name for the class would then be Actinomycetia Salam et al. 2020. By keeping Rule 8 retroactive,
the ICSP would express its preference for the consistent application of a naming scheme over the stability of names. It would then
be logical to prefer Actinomycetia over Actinomycetes and Actinobacteria. Adding a nomenclatural type to the latter two names
would do no harm in that case and would render it easier to recognize the three names as synonyms of each other.
By making Rule 8 non- retroactive, the ICSP would express its preference for the stability of names over the consistent application
of a naming scheme. It would then be logical to prefer Actinomycetes or Actinobacteria over Actinomycetia. Adding a nomenclatural
type to at least one of the former two names would be the means to replace Actinomycetia Salam et al. 2020 as the correct name.
It follows that establishing a nomenclatural type for Actinomycetes Krassilnikov 1949 (Approved Lists 1980) or Actinobacteria
Stackebrandt et al. 1997 or both is the preferred solution irrespective of the outcome of the forthcoming decision by the ICSP.
Even if Rule 8 was made non- retroactive, the only possibility to render Actinobacteria Stackebrandt et al. 1997 the correct
name of the class is to not also assign a nomenclatural type to Actinomycetes Krassilnikov 1949 (Approved Lists 1980) because
otherwise Actinomycetes would become the correct name. Oren [75] preferred Actinobacteria because it is the more widely
known name. Arguments for Actinomycetes can be found, however [81], even apart from the fact that its relationship to the
name Actinomycetales Buchanan 1917] (Approved Lists 1980) is more obvious than the one of Actinobacteria Stackebrandt
et al. 1997.
First, the name Actinomycetes was included in the Approved Lists of Bacterial Names [4] and thus was potentially known
to every microbiologist. It could accordingly be regarded as unfair to prefer Actinobacteria Stackebrandt et al. 1997. Second,
Actinomycetes Krassilnikov 1949 (Approved Lists 1980) was preferred in a previous publication of the Judicial Commission [81],
which emphasized that this name remained in use and even already gave Actinomycetales Buchanan 1917 (Approved Lists 1980)
as the nomenclatural type although a type is not mentioned in the Approved Lists of Bacterial Names [4]. Euzéby and Tindall
[82] also emphasized that Actinomycetes Krassilnikov 1949 (Approved Lists 1980) was in use although they did not mention
a nomenclatural type. It should not be overlooked that ‘actinomycetes’ is a vernacular name frequently used for this group of
bacteria. ird, most of the names of classes which currently conict with the wording of Rule 8 do so because their ending
deviates from - ia [20]. Like Deferribacteres Huber and Stetter 2002 [83, 84], Actinomycetes Krassilnikov 1949 (Approved Lists
1980) uses - es. In contrast, Actinobacteria Stackebrandt et al. 1997 is one of those comparatively rare cases in which the name of
a class is not formed from the stem of the name of a nomenclatural type. Fourth, Actinomycetes ts better than Actinobacteria to
the now validly published name of the phylum, Actinomycetota Goodfellow 2021 [85]. Last but not least, the disease caused by
the genus Actinomyces, well recognized by clinicians, is called actinomycosis [86], hence it is easier to relate names derived from
the name Actinomyces to this medical condition.
Eleven commissioners voted for assigning Actinomycetales Buchanan 1917 (Approved Lists 1980) as the nomenclatural type of
Actinomycetes Krassilnikov 1949 (Approved Lists 1980), one commissioner opposed this solution. Ten commissioners opted for
assigning Actinomycetales Buchanan 1917 (Approved Lists 1980) as the nomenclatural type of Actinobacteria Stackebrandt et
al. 1997, two commissioners opposed.
OPINION 120
A Request for an Opinion by Oren [87] proposed the orthographical correction of the name Amycolatopsis albidoavus Lee and
Hah 2001 [88, 89] to Amycolatopsis albidiava or Amycolatopsis albidoava. e Judicial Commission agrees with Oren [87] that
the gender of the genus name would call for albidiava or albidoava as the epithet. Moreover, Appendix 9 section A(1b) of the
ICNP indicates that in compound names or epithets the connecting vowel is - i- when preceded by a word element of Latin origin
[5]. is would yield albidiava instead of albidoava [87].
It was highlighted in Judicial Opinion 105 [10] that the Judicial Commission can conduct orthographical corrections but is not
normally obliged to do so. It must be noted, however, that the correction of albidoavus to albidoava is a purely grammatical
correction while the correction of albidoavus to albidiava is also an orthographical correction [10]. e note to Rule 61 of the
ICNP [5] restricts orthographical corrections (by any authors except for the Judicial Commission [10]) as follows:
“Except for changes of gender in specic epithets when species are transferred to other genera (comb. nov.) no grammatical
or orthographic corrections will be accepted for names on the Approved Lists of Bacterial Names, the Validation Lists and the
Notication Lists.”
at is, a grammatical correction like the one from albidoavus to albidoava could be conducted by any author at any time
if the name using this epithet was a new combination and the genus name of the basonym was in the masculine gender while
the genus name of the new combination was in the feminine gender. While the Judicial Commission would not need to be
invoked in such cases, Amycolatopsis albidoavus Lee and Hah 2001 is a new species and not a new combination. A combined
grammatical–orthographical correction such as the one from albidoavus to albidiava can only be conducted by the Judicial
Commission irrespective of whether or not the name is a new combination.
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us there are three options: to not conduct any correction, to grammatically correct the name to albidoava, and to grammatically
and orthographically correct the name to albidiava. While all commissioners opted for correcting the name, a slight majority of
seven commissioners preferred to only grammatically correct the name and ve opted for the orthographical correction.
Rule 61 is not particularly specic regarding the kind of publication within which authors can conduct grammatical corrections of
species epithets of new combinations. It appears that any kind of publication could be used, irrespective of, e.g., a mention within
the International Journal of Systematic and Evolutionary Microbiology (IJSEM). is has the potential disadvantage that gram-
matical corrections are not noticed, potentially causing confusion. For this reason, the Judicial Commission has pre- emptively
compiled a list of grammatical corrections which could be done by anybody in Table4. is list is restricted to cases in which
the basonym is a validly published name whose genus name has a gender that diers from the gender of the new combination
[90–93], in accordance with Rule 61 of the ICNP [5]. Eleven commissioners opted for conducting the grammatical corrections
listed in Table4, one commissioner abstained.
It is not clear why the section of Rule 61 cited above refers only to species epithets but not to subspecies epithets. Shortcomings
of the wording of Rule 61 were already observed in Opinion 105 [10]. e additional problems recognized here may call for a
revision of this rule but these issues are beyond the scope of a Judicial Opinion.
OPINION 121
Rule 23a Note 4 and Rule 56a of the ICNP stipulate that the Judicial Commission can place names on the list of rejected names
[5]. Rule 56a lists the established justications for rejecting a name. Rule 23a Note 4 and Rule 56b stipulate that the Judicial
Commission can place names on the list of conserved names. e ICNP does not contain any rules, however, which indicate
that the Judicial Commission can remove names from the list of rejected names or from the list of conserved names, although
a previous Opinion could be revised.
Judicial Opinion 69 [94] rejected the name Clostridium putricum (Trevisan 1889) Reddish and Rettger 1922 (Approved Lists
1980) [4, 95], conserved the name Clostridium botulinum (van Ermengem 1896) Bergey et al. 1923 (Approved Lists 1980) [4, 96]
for toxigenic strains, and conserved the name Clostridium sporogenes (Metchniko 1908) Bergey et al. 1923(Approved Lists 1980)
[4, 96] for nontoxigenic strains.
Dobritsa and colleagues [97], who conducted a remarkable empirical study, requested a revision of Opinion 69. Since Opinion
69 was only dealing with the rejection and conservation of names, this Request for an Opinion needs to be related to the fact
that the ICNP does not provide any mechanism for ‘unrejecting’ or ‘unconserving’ a name. On the other hand, a revision of an
Opinion appears to be possible; the Judicial Commission is bound by the Statutes of the ICSP [98] as well as by the wording of
the ICNP. However, a closer look at the implications of Opinion 69 is nevertheless warranted because the problems supposed to
be caused by that Judicial Opinion may or may not be real.
In particular, it must be taken into account that the rejection of Clostridium putricum (Trevisan 1889) Reddish and Rettger
1922 (Approved Lists 1980) is an example for the rejection of a name as a nomen periculosum according to Rule 56a [5, 94, 99].
A precedent for the application of this rule is Opinion 60 [100, 101]. e note to Rule 56a [5, 5] may occasionally be overlooked
but it is actually crucial [10]. is note stipulates:
“is application is restricted to a proposed change in the specic epithet of a nomenspecies which is widely recognized as
contagious, virulent, or highly toxigenic, for example, to that of a subspecies of a species having a dierent host range or a degree
of contagiousness or virulence. If the Judicial Commission recognizes a high order of risk to health, or of serious economic
Table 4. Grammatical corrections of species epithets in validly published names that are new combinations that had required a change of the gender
of the epithet
As such corrections could be made by any author, they are conducted here en bloc for providing a single literature source.
Taxon name Grammatical correction
Hyphomonas neptunium (Leifson 1964) Moore et al. 1984 Hyphomonas neptunia corrig (Leifson 1964) Moore et al. 1984
Pectobacterium carnegieana (Standring 1942) Brenner et al. 1973 (Approved Lists 1980) Pectobacterium carneg ieanum corrig. (Standring 1942) Brenner et al. 1973 (Approved Lists
1980)
Salinilum aidingensis (Xia et al. 2017) Moshtaghi Nikou et al. 2017 Salinilum aidingens e corrig. (Xia et al. 2017) Moshtaghi Nikou et al. 2017
Salinilum ghardaiensis (Meklat et al. 2014) Moshtaghi Nikou et al. 2017 Salinilum ghardaiense corrig. (Meklat et al. 2014) Moshtaghi Nikou et al. 2017
Streptomyces ladakanum (Hanka et al. 1966) Witt and Stackebrandt 1991 Streptomyces ladakanus corrig. (Hanka et al. 1966) Witt and Stackebrandt 1991
Streptomyces morookaense (Locci and Schoeld 1989) Witt and Stackebrandt 1991 Streptomyces morookaensi s corrig. (Locci and Schoeld 1989) Witt and Stackebrandt 1991
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consequences, an Opinion may be issued that the taxon be maintained as a separate nomenspecies, without prejudice to the
recognition or acceptance of its genetic relatedness to another taxon.”
Accordingly, the purpose of Opinion 69 was solely to retain both Clostridium botulinum (van Ermengem 1896) Bergey et al.
1923 (Approved Lists 1980) and Clostridium sporogenes (Metchniko 1908) Bergey et al. 1923 (Approved Lists 1980) as separate
nomenspecies (species by name only). is means that if a strain is supposed to belong to either Clostridium botulinum or
Clostridium sporogenes or both, the correct species name of the strain is Clostridium botulinum if the strain is toxigenic but is
Clostridium sporogenes if the strain is nontoxigenic. e two species names are only conserved against each other. Opinion 69
does not apply to strains that are not supposed to belong to Clostridium botulinum and are not supposed to belong to Clostridium
sporogenes.
In contrast, Dobritsa et al. [97] seem to believe that Opinion 69 hinders taxonomists to propose new species names for toxigenic
strains even if these strains are neither regarded as conspecic with Clostridium botulinum nor as conspecic with Clostridium
sporogenes. ese authors [97] claim:
“e goal of the Request for an Opinion was to prevent a confusion, but the interpretation of Opinion 69 in this form, i.e. that
all strains of neurotoxin- producing clostridia should be identied as C. botulinum, generated another taxonomic problem since
toxigenic clostridia are much more diverse than had been assumed.”
is concern is understandable as such, but the wordings of the ICNP [5], of Judicial Opinion 69 [94] and of the underlying
Request for an Opinion [99] do not appear to support this interpretation. Although taxonomic freedom is a valuable goal in its own
right [5], the taxonomic freedom Dobritsa et al. [97] intend to restore in this specic case was not in danger in the rst place. e
Judicial Commission thus decided to deny this Request for an Opinion [97]. is solution was favoured by all 12 commissioners.
OPINION 122
e Request for an Opinion by Balish et al. [102] calls for the rejection of taxon names of Mollicutes that were proposed in a
recent taxonomic study [103] and validly published [104] under the ICNP [5].
Gupta and Oren [105] criticized that Request for an Opinion mainly for taxonomical reasons, although some references to the ICNP
[5] were made by these authors. e Judicial Commission does not rule on purely taxonomic questions [106] and has to base its
treatment of a Request for an Opinion on the wording of the ICNP, as indicated in Article 7(a)(1) of the statutes of the ICSP [98]. e
opening sentence of Article 6(b)(5) is also of relevance in this context. Previously issued Judicial Opinions may assist in interpreting
the ICNP [10].
Requests for the conservation and rejection of names thus stand or fall by their compatibility with the ICNP [10, 94, 99–101].
Unfortunately, the Request for an Opinion by Balish et al. [102] contains a number of misinterpretations of the ICNP, which need to
be claried. We will here address them in turn, following the eight subheadings given in the Request. Finally, alternative ways to solve
the perceived problem are delineated.
‘Aim at stability of names’
First, Principle 1(1) of the ICNP does not prohibit taxonomic revisions. Principle 1(1) is immediately counterbalanced by Principle
1(4), which Balish et al. [102] do not mention, and further specied by Principles 1(2) and 1(3). General Consideration 4, Principle 8,
Principle 9, and numerous rules of the ICNP [5] also point into the same direction, namely that the ICNP ensures taxonomic freedom
by providing for the possibility to propose new names, if necessary with the purpose of replacing other names, to conduct taxonomic
rearrangements. While the ICSP does aim at the stability of names, this must not be interpreted so as to preclude reclassications.
One of the crucial issues here is that names proposed as the result of a taxonomic revision such as the one conducted by Gupta et al.
[103] are not ‘useless’ from the perspective of the ICNP, as explained below, and thus do not conict with the aim that names be stable.
In contrast, Rule 55 lists a couple of misinterpretations that could cause the creation of useless names. e rst sentence of Rule 37b
also describes a situation that could possibly create a useless name, but the same rule also lists four situations in which the creation
of a name may be necessary (an issue to which we will return). Principle 8 and Rule 23 a are also worth consultation. Rules 39 a, 40 a,
51b(1) and 51b(2) are further examples for how the ICNP aims at the stability of names without sacricing taxonomic freedom.
‘Avoid or reject the use of names which may cause error or confusion’
Second, the ICNP [5] denes names which may cause error or confusion distinctly from the Request for an Opinion [102].
Balish et al. advocate for regarding each name proposed by Gupta et al. [103] as perilous name (nomen periculosum). However,
the note to Rule 56 a(5) clearly indicates that a name can only be rejected as a perilous name (nomen periculosum) in order to
retain separate nomenspecies (species by name only). is is also obvious from the previous Judicial Opinions which applied
Rule 56 a [5, 94, 101], in conjunction with the underlying Requests for an Opinion [99, 100]. A thorough reading of the ICNP
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reveals that the notes are an integral part of the general considerations, principles, rules and recommendations and thus must
not be disregarded. A proposal [107] is under consideration by the ICSP to explicitly explain this role of the notes in the ICNP.
A name can indeed be rejected if it causes confusion, but the ICNP denes a name causing confusion (nomen confusum) in Rule
56a(3) as a name based on a mixed culture. Balish et al. [102] did not provide evidence that the names proposed by Gupta et al.
[103] were based on mixed cultures. e ICNP does not treat the proposal of new combinations as confusing. In contrast, the
ICNP precisely species the conditions under which a new combination must be proposed, as explained below.
In general, the rejection of names is not a means of resolving taxonomic controversies. is is obvious from several sections of the
ICNP, including Rule 56 a itself, which implements Principle 1(2). Appendix 4 of the ICNP [5] lists all rejected names. Readers
are invited to study the reasons for rejection given in the accompanying Requests for an Opinion.
‘Avoid the useless creation of names’
ird, names proposed as the outcome of a taxonomic revision like the one considered here [103] do not contravene Principle
1(3). For the ICNP, such a taxonomic revision is not a ‘useless creation of names’. is is obvious from General Consideration 4,
from Principle 1(4), from Principle 8, from Principle 9, and from numerous rules of the ICNP. It is indeed not advisable to attempt
to infer the meaning of the Principles of the ICNP solely from their wording. One should also carefully consider the wording of
the Rules which implement each Principle. A signicant proportion of the rules of the ICNP is devoted to regulating how names
can be proposed. is includes the proposal of new combinations, which are a means of indicating that a species should obtain a
distinct position, i.e. be assigned to another genus, as stipulated by Rule 37b(2) and Rule 41. is is also obvious from Principle
8 and Rule 23 a of the ICNP [5].
Since the publication of the Approved Lists of Bacterial Names [4], several thousands of new combinations were validly
published under the ICNP. At the time of writing, the List of Prokaryotic Names with Standing in Nomenclature [52] lists
more than 3750 validly published new combinations. If one followed the argumentation of Balish et al. [102], all of these
names would probably have to be rejected, since much of the reasoning in that Request for an Opinion could equally be
applied to names other than those recently proposed in Mollicutes [103]. e Request for an Opinion [102] states that
“Because the original names would retain standing in nomenclature such that either name could be used …, the changes would
destabilize the nomenclature for microbiologists and regulatory agencies who actually use these names to refer to living organisms
for practical purposes.”
However, the valid publication of every new combination proposed for a validly published name, either in Mollicutes or
in any other group of Prokaryotes, causes the creation of a validly published synonym of a name that retains standing
in nomenclature, i.e. remains validly published [5, 108, 109]. In fact, if Principles 1(1), 1(2) and 1(3) were interpreted as
suggested by Balish et al. [102], namely by disregarding General Consideration 4 and Principle 1(4) and the many rules
which implement that principle, all of the more than 3750 validly published new combinations would contravene the ICNP.
Balish et al. [102] appear to regard a name as ‘useless’ if it originates from a taxonomic revision which they believe to be
unnecessary. is, however, cannot be meant by the wording of Principle 1(3) of the ICNP [5] because if so it would explicitly
contravene General Consideration 4 and Principle 1(4) and implicitly contravene all the rules of the ICNP that implement
the proposal of new combinations. If authors could dene whether or not taxon names proposed by other authors are useless,
this would give some authors a licence to restrict the taxonomic freedom of others although this freedom is guaranteed by
the ICNP. Moreover, one cannot seriously expect the ICNP to elaborately cater for enabling certain taxonomic actions on
the one hand and at the same time to regard those actions as resulting in useless names on the other hand.
As indicated in Article 6(b)(5)(c) of the statutes of the ICSP [98], not even the Subcommittees on Taxonomy can legislate on
classication. In contrast, as stipulated in the opening sentence of Article 6(b)(5), the Subcommittees on Taxonomy work
within framework of the ICNP, and the ICNP does not legislate on classication either [106]. is also holds for the Judicial
Commission, hence Article 7(a)(7) and Article 6(b)(5)(d) have to be understood in the context of Article 7(a)(1) and the
opening sentence of Article 6(b)(5), respectively.
‘The purpose of giving a name to a taxon is not to indicate the history of the taxon’
Fourth, names proposed as the outcome of a taxonomic revision do not contravene Principle 4, even if the purpose of the
taxonomic revision was the adaptation of the classication to the evolutionary history of the classied organisms by attempting
to create monophyletic taxa throughout or by other means, if any. Such an approach to classication is, of course, not mandated
by the ICNP, but it is certainly permitted. e wording of Principle 4 does not rule out that a name can ‘indicate the characters
or the history of the taxon’. It is indeed not even clear whether this phrasing refers to the evolutionary history of a taxon, as
apparently supposed by Balish et al. [102]. e wording of the ICNP [5] does not rule out that this sentence has the history of
cultivation or transfer of strains or the history of taxonomic treatments of the group in mind. In fact, the phrasing of the current
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Principle 4 originates from Principle 8 of the 1948 code [110], hardly a time at which the classication of organisms according
to their evolutionary history was a widespread approach.
Moreover, Principle 4 appears to address the way names are formed rather than whether or not new names can be proposed when
a reclassication is conducted. Authors who intend to create a classication that better reects the evolutionary history of the
classied organisms can propose new taxon names. e ICNP provides for doing so and claries under which conditions such
names are validly published. Such newly proposed and validly published names do not need themselves to indicate ‘the history
of the taxon’ to achieve this goal. Taxon names can be formed in various ways, including a derivation from personal names, from
geographic locations, or from phenotypic or other features of an organism. Details are provided in Appendix 9 of the ICNP, and
several rules and recommendations provide further guidance [5].
e evolutionary history of the classied organisms can be reected by the manner in which species are arranged into genera,
genera into families, families into orders, and so on. But this can work independently of the way the names of these taxa are
actually formed. For instance, a genus name such as Allofrancisella Qu et al. 2016 does reect the evolutionary history, as it was
coined to indicate that this genus is phylogenetically close to the genus Francisella [111]. A genus name such as Malacoplasma
Gupta et al. 2018 [103, 104] does not by itself reect the evolutionary history of any organism.
e ICNP [5] does not specify in which way taxonomy shall be conducted [106]. However, the ICSP statutes [98] are also of
relevance in this context. Intriguingly, whereas the other paragraphs of Article 6(b)(5) deal with nomenclature and taxonomy,
Article 6(b)(5)(a) indicates that a Subcommittee on Taxonomy should:
“Encourage and undertake research on the evolutionary relationships among the organisms in the taxa under study.”
e statutes [98] do not explicitly indicate that the taxonomic classication should be based on the evolutionary relationships,
but if this option was ruled out [102], one wonders why phylogenetic relationships should be researched or encouraged by a
Subcommittee on Taxonomy in the rst place. It is questionable whether taxonomists would be encouraged to study evolutionary
relationships if names resulting from a phylogeny- based reclassication were rejected although they were agreement with the
ICNP [5].
‘The name of a taxon should not be changed without sucient reason’
Fih, names proposed as the outcome of a taxonomic revision such as the one conducted by Gupta et al. [103] do not contravene
Principle 9. is is obvious from the wording of Principle 9 itself, as well as from General Consideration 4, Principle 1(4),
Principle 8, and from numerous rules of the ICNP [5], as explained above. While we agree with Balish et al. [102] that the ‘extant
nomenclature’ of Mollicutes is not ‘contrary to the Code’, the replacement of illegitimate names (Rule 23 a Note 5) is only one of
the two sucient reasons for changing a name given in Principle 9. e other reason given is the conduct of ‘further taxonomic
studies’, which Gupta et al. [103] undoubtedly have done. Principle 9 does not restrict these to studies whose resulting taxonomic
changes someone else nds necessary. Balish et al. [102] claim that one should ‘avoid nomenclatural destabilization and the risk
of errors and confusion that the new names introduce’.
Again, this argument could equally be applied, or have been applied, to all of the more than 3750 new combinations that are at
present validly published under the ICNP [52]. While many of them may nowadays be well known, all of them were new when
they were proposed.
‘Avoid names that are very long or dicult to pronounce’
Sixth, names cannot be rejected just because they contravene a recommendation. is is obvious from General Consideration
6(3) and other sections of the ICNP, such as Rule 56 a [5]. Apart from that, the family names proposed by Gupta et al. [103] and
criticized by Balish et al. [102] as contravening Recommendation 6(1) have a length of 17 and 20 characters, respectively. At the
time of writing, the List of Prokaryotic Names with standing in Nomenclature [52] claims that names of families validly published
under the ICNP are 8 to 26 characters long with a median length of 16 characters and an average length of 16.21 characters. It is
thus questionable whether the family names proposed by Gupta et al. [103] are exceptionally long. Whether they are ‘awkward
to pronounce’ is dicult to conclude and so remains a matter of opinion.
‘A name is not validly published If it was proposed in anticipation of the future acceptance of a particular
circumscription’
Seventh, the wording of Rule 28b and the examples given therein clearly indicate that Rule 28b(2), which states that a name is
not validly published if it was merely proposed in anticipation of some future event, only refers to an anticipation made by the
authors of that name, not to one made by another party. Rule 28b(2) thus does not refer to the acceptance of a name by other
taxonomists. If it did, it would contravene General Consideration 4 and Principle 1(4). As obvious from Principle 7 and Rule 27,
the concept of the valid publication of a name is of central importance to the ICNP [5]. us whether or not a name is validly
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published cannot depend on the mere taxonomic opinion of another party. As an aside, it must not be overlooked that names that
are not validly published have no claim to recognition under the ICNP anyway, hence it would not make sense to reject them [10].
‘A change in the name of a taxon is not warranted by an alteration of the diagnostic characters or of the
circumscription’
Eighth, the proposals of new genus names and new combinations in Mollicutes [103, 104] do not contravene Rule 37b. In contrast,
Rule 37b(2), which Balish et al. [102] do not mention, clearly indicates that the change of a name of a taxon is required upon
transfer, which includes the transfer of a species to another genus as specied in Rule 41 a. In fact, the taxonomic work by Gupta
et al. mainly comprises such transfers [103, 104]. Since the change of a name upon transfer is mandatory in the ICNP, it cannot
constitute a ‘useless creation’ of a name as indicated in Principle 1(3). Balish et al. [102] only referred to the rst sentence of Rule
37b, but this sentence apparently does not apply to cases covered by clauses 37b(1) to 37b(4). e rst sentence of Rule 37b covers
cases which can be solved be an emendation of the description of a taxon.
e names above species rank proposed by Gupta et al. [103, 104] are new names (marked as gen. nov., fam. nov. or ord. nov.) and
their proposal is not a ‘change in the name of a taxon’, hence Rule 37b does not apply to them. Nor are these proposals examples
of a ‘useless creation of names’ as indicated in Principle 1(3), as they serve an obvious taxonomic purpose. is holds irrespective
of whether or not other parties agree with that purpose.
THE CONSEQUENCES OF TAXONOMIC FREEDOM
Guaranteeing taxonomic freedom is one of the cornerstones of the ICNP [5, 108]. Crucially, this works in both directions. While
authors can validly publish new combinations which they intend to be used instead of already validly published species names,
other scholars need not follow these proposals. ey can still use the older names [112] and nevertheless be in compliance with
the ICNP. e ICNP itself does not enforce the renaming of taxa, except for the possible replacement of illegitimate names as
indicated in Principle 9 and Rule 51 a [5]. e perceived renaming of taxa, if any, is thus almost exclusively conducted in scientic
publications which use taxon names and in databases which store taxon names.
While the curators of some databases may erroneously believe that they must always use the most recent taxon name among a set
of validly published and legitimate synonyms, or regard this as a mere convention to be followed, there is no need to do so. e
authors of the Request for an Opinion [102] can appeal to the curators of public databases to use the older names of Mollicutes
in place of the synonyms proposed and validly published more recently [103, 104]. If successful, this might well have the desired
eect on scientic publications, too. If unsuccessful, there might or might not be a good reason for that outcome.
Changes of names in public databases are indeed a well- known cause of short- term dissatisfaction [106]. A potential solution is
the introduction of a grace period before replacing the preferred names in public databases. Forthcoming replacements could be
announced in advance on the websites of such databases, thus giving the users an opportunity to brace themselves for taxonomic
changes in the future, and possibly to also critically comment on the plans.
In contrast to such measures, the rejection of names by the Judicial Commission is not a means of solving taxonomic controversies
[5, 98, 106, 108]. Such controversies should be tolerated and subjected to an open scientic debate [113]. Names which do not
contravene the ICNP and do not t to any of the reasons given in the ICNP for rejecting a name cannot be rejected. Scholars who
are dissatised with this outcome are invited to propose an according modication of the ICNP in the IJSEM. In the meantime,
the Judicial Commission is bound to the wording of the present revision of that code [5, 98]. Moreover, while a number of
proposed revisions of the ICNP are currently under consideration [22, 23], none of them would aect the interpretation of this
Request for an Opinion [102].
For the reasons given above, the Judicial Commission does not see a possibility to grant this Request for an Opinion. is conclu-
sion can, and has to, be reached without resorting to any consideration of the taxonomic merits (or lack thereof) of the work by
Gupta et al. in Mollicutes [103]. e Judicial Commission thus decided to deny this request [102]. is solution was favoured by
11 commissioners, with one abstention.
Funding information
The authors received no specific grant from any funding agency.
Acknowledgements
We are grateful for the information provided by Russell Hill, IMET, Baltimore/USA, on strain JZ11IS74. Stefan Emler, SmartGene, Lausanne/Switzer-
land, provided helpful comments on public databases, which are gratefully acknowledged.
Conflicts of interest
The authors declare that there are no conflicts of interest.
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References
1. Velázquez E, Flores- Félix JD, Sánchez- Juanes F, González- JM,
Peix A. The status of the genus Seliberia Aristovskaya and Parinkina
1963 (Approved Lists 1980) and the species Seliberia stellate Aris-
tovskaya and Parinkina 1963 (Approved Lists 1980). Request for an
Opinion. Int J Syst Evol Microbiol 2015;65:2337–2340.
2. Aristovskaya TV, Parinkina OM. A new soil microorganism
Seliberia stellata n. gen. n. sp. (in Russian). Bull Acad Sci USSR
1963;218:49–56.
3. Aristovskaya TV. Genus Seliberia Aristovskaya and Parinkina
1963, 56. In: Buchanan RE and Gibbons NE (eds). Bergey’s Manual
of Determinative Bacteriology, 8th edn. Baltimore, MD: Williams &
Wilkins; 1974. p. 160.
4. Sneath PHA, McGowan V, Skerman VBD. Approved Lists of Bacte-
rial Names. Int J Syst Bacteriol 1980;30:225–420.
5. Parker CT, Tindall BJ, Garrity GM. International Code of Nomen-
clature of Prokaryotes. Int J Syst Evol Microbiol 2019;69:S1–S111.
6. Tindall BJ. What does Rule 18c of the International Code of
Nomenclature of Bacteria really say? Int J Syst Evol Microbiol
2016;66:3622–3624.
7. Rameshkumar N. The status of the species Shewanella irciniae
Lee et al. 2006. Request for an opinion. Int J Syst Evol Microbiol
2015;65:2774.
8. Lee OO, Lau SCK, Tsoi MMY, Li X, Plakhotnikova I, etal. Shewanella
irciniae sp. nov., a novel member of the family Shewanellaceae,
isolated from the marine sponge Ircinia dendroides in the Bay
of Villefranche, Mediterranean Sea. Int J Syst Evol Microbiol
2006;56:2871–2877.
9. Arahal DR. Opinions 100, 101 and 102. Int J Syst Evol Microbiol
2020;70:5177–5181.
10. Arahal DR, Busse H- J, Bull CT, Christensen H, Chuvochina M, etal.
Judicial Opinions 103- 111. Int J Syst Evol Microbiol 2022;72:5197.
11. Shida O, Takagi H, Kadowaki K, Komagata K. Proposal for two
new genera, Brevibacillus gen. nov. and Aneurinibacillus gen. nov.
Int J Syst Bacteriol 1996;46:939–946.
12. Kämpfer P, Doijad S, Chakraborty T, Glaeser SP. The status
of the species Enterobacter siamensis Khunthongpan et
al. 2014. Request for an Opinion. Int J Syst Evol Microbiol
2016;66:524–525.
13. Khunthongpan S, Bourneow C, H- Kittikun A, Tanasupawat S,
Benjakul S, etal. Enterobacter siamensis sp. nov., a transglutaminase-
producing bacterium isolated from seafood processing wastewater
in Thailand. J Gen Appl Microbiol 2013;59:135–140.
14. Oren A, Garrity GM. List of new names and new combinations
previously eectively, but not validly, published. Int J Syst Evol
Microbiol 2014;64:2927–2929. ;
15. Kimura ZI, Hoshino T, Murakami K. The status of the species
Moorella thermoautotrophica Wiegel et al. 1981. Request for an
Opinion. Int J Syst Evol Microbiol 2016;66:3249–3251.
16. Wiegel J, Braun M, Gottschalk G. Clostridium thermoautotrophicum
species novum, a thermophile producing acetate from molecular
hydrogen and carbon dioxide. Curr Microbiol 1981;5:255–260.
17. Collins MD, Lawson PA, Willems A, Cordoba JJ, Fernandez-
Garayzabal J, etal. The phylogeny of the genus Clostridium: proposal
of five new genera and eleven new species combinations. Int J Syst
Bacteriol 1994;44:812–826.
18. Nepomnyashchaya YN, Slobodkina GB, Baslerov RV, Chernyh NA,
Bonch- Osmolovskaya EA, et al. Moorella humiferrea sp. nov., a
thermophilic, anaerobic bacterium capable of growth via elec-
tron shuttling between humic acid and Fe(III). Int J Syst Evol
Microbiol 2012;62:613–617.
19. Redl S, Poehlein A, Esser C, Bengelsdorf FR, Jensen TØ, etal.
Genome- based comparison of all species of the genus Moorella,
and status of the species Moorella thermoacetica and Moorella
thermoautotrophica. Front Microbiol 2020;10:30–70.
20. Oren A, Parte A, Garrity GM. Implementation of rule 8 of the Inter-
national Code of Nomenclature of Prokaryotes for the renaming
of classes. Request for an opinion. Int J Syst Evol Microbiol
2016;66:4296–4298.
21. Tindall BJ. The undesirable retroactive changes to Rule 8 of the
International Code of Nomenclature of Prokaryotes. Int J Syst
Evol Microbiol 2016;66:4895–4896.
22. Oren A, Arahal DR, Rosselló-Móra R, Sutclie IC, Moore ERB.
Public discussion on a proposed revision of the International
Code of Nomenclature of Prokaryotes. Int J Syst Evol Microbiol
2021;71:4918.
23. Oren A, Arahal DR, Rosselló-Móra R, Sutclie IC, Moore ERB.
Preparing a revision of the International Code of Nomenclature
of Prokaryotes. Int J Syst Evol Microbiol 2021;71:4598.
24. Boden R, Hutt LP, Rae AW. Reclassification of Thiobacillus aquae-
sulis (Wood & Kelly, 1995) as Annwoodia aquaesulis gen. nov.,
comb. nov., transfer of Thiobacillus (Beijerinck, 1904) from the
Hydrogenophilales to the Nitrosomonadales, proposal of Hydrog-
enophilalia class. nov. within the “Proteobacteria”, and four new
families within the orders Nitrosomonadales and Rhodocyclales.
Int J Syst Evol Microbiol 2017;67:1191–1205.
25. García- López M, Meier- Koltho JP, Tindall BJ, Gronow S,
Woyke T, etal. Analysis of 1,000 type- strain genomes improves
taxonomic classification of Bacteroidetes. Front Microbiol
2019;10:2083.
26. Pascual J, García- López M, Bills GF, Genilloud O. Longimicrobium
terrae gen. nov., sp. nov., an oligotrophic bacterium of the under-
represented phylum Gemmatimonadetes isolated through a
system of miniaturized diusion chambers. Int J Syst Evol Micro-
biol 2016;66:1976–1985.
27. Spring S, Bunk B, Spröer C, Schumann P, Rohde M, etal. Charac-
terization of the first cultured representative of Verrucomicrobia
subdivision 5 indicates the proposal of a novel phylum. ISME J
2016;10:2801–2816.
28. Zheng H, Dietrich C, Radek R, Brune A. Endomicrobium
proavitum, the first isolate of Endomicrobia class. nov. (phylum
Elusimicrobia)--an ultramicrobacterium with an unusual cell
cycle that fixes nitrogen with a Group IV nitrogenase. Environ
Microbiol 2016;18:191–204.
29. Tahon G, Tytgat B, Lebbe L, Carlier A, Willems A. Abditibacterium
utsteinense sp. nov., the first cultivated member of candidate
phylum FBP, isolated from ice- free Antarctic soil samples. Syst
Appl Microbiol 2018;41:279–290.
30. Waite DW, Chuvochina M, Pelikan C, Parks DH, Yilmaz P, et al.
Proposal to reclassify the proteobacterial classes Deltaproteo-
bacteria and Oligoflexia, and the phylum Thermodesulfobacteria
into four phyla reflecting major functional capabilities. Int J Syst
Evol Microbiol 2020;70:5972–6016.
31. Grant WD, Kamekura M, McGenity TJ, Ventosa A. Class III. Halo-
bacteria class. nov. In: Boone DR, Castenholz RW and Garrity GM
(eds). Bergey’s Manual of Systematic Bacteriology, 2nd edn, vol. 1.
New York: Springer; 2001. pp. 294–334.
32. Boone DR. Class I. Methanobacteria class. nov. In: Boone DR,
Castenholz RW and Garrity GM (eds). Bergey’s Manual of System-
atic Bacteriology, 2nd edn, vol. 1. New York: Springer; 2001. pp.
213–235.
33. Garrity GM, Holt JG. Class I. Thermomicrobia class. nov. In: Boone
DR, Castenholz RW and Garrity GM (eds). Bergey’s Manual of
Systematic Bacteriology, 2nd edn, vol. 1. New York: Springer;
2001. pp. 447–450.
34. Hatchikian EC, Ollivier B, Garcia JL. Class I. Thermodesulfobac-
teria class. nov. In: Boone DR, Castenholz RW and Garrity GM
(eds). Bergey’s Manual of Systematic Bacteriology, 2nd edn, vol. 1.
New York: Springer; 2001. pp. 389–394.
35. Geissinger O, Herlemann DPR, Mörschel E, Maier UG, Brune A.
The ultramicrobacterium “Elusimicrobium minutum” gen. nov.,
sp. nov., the first cultivated representative of the termite group 1
phylum. Appl Environ Microbiol 2009;75:2831–2840.
36. Rainey FAetal. Class II Clostridia class. nov. In: De Vos P, Garrity
GM, Jones D, Krieg NR and Ludwig W (eds). Bergey’s Manual of
19
Arahal etal., Int. J. Syst. Evol. Microbiol. 2022;72:005481
Systematic Bacteriology, 2nd edn, vol. 3. New York: Springer;
2009. p. 736.
37. Iino T, Mori K, Uchino Y, Nakagawa T, Harayama S, et al. Ignavi-
bacterium album gen. nov., sp. nov., a moderately thermophilic
anaerobic bacterium isolated from microbial mats at a terres-
trial hot spring and proposal of Ignavibacteria classis nov., for a
novel lineage at the periphery of green sulfur bacteria. Int J Syst
Evol Microbiol 2010;60:1376–1382.
38. Stackebrandt E, Rainey FA, Ward- rainey NL. Proposal for a new
hierarchic classification system, Actinobacteria classis nov. Int J
Syst Bacteriol 1997;47:479–491.
39. Reysenbach AL. Class IV. Thermoplasmata class. nov. In: Boone
DR, Castenholz RW and Garrity GM (eds). Bergey’s Manual of
Systematic Bacteriology, 2nd edn, vol. 1. New York: Springer;
2001. pp. 335–340.
40. Rahn O. New principles for the classification of bacteria. Zentral-
blatt fur Bakteriologie, Parasitenkunde, Infektionskrankheiten und
Hygiene Abteilung II 1937;96:273–286.
41. Catlin BW. Notes: Branhamaceae fam. nov., a proposed family to
accommodate the genera Branhamella and Moraxella. Int J Syst
Bacteriol 1991;41:320–323.
42. Larkin JM, Borrall R. Notes: Spirosomaceae, a new family to
contain the genera Spirosoma Migula 1894, Flectobacillus Larkin
et al. 1977, and Runella Larkin and Williams 1978. Int J Syst
Bacteriol 1978;28:595–596.
43. Rainey FA, Ward- Rainey N, Kroppenstedt RM, Stackebrandt E.
The genus Nocardiopsis represents a phylogenetically coherent
taxon and a distinct actinomycete lineage: proposal of Nocardiop-
saceae fam. nov. Int J Syst Bacteriol 1996;46:1088–1092.
44. Golyshina OV, Pivovarova TA, Karavaiko GI, Kondratéva TF,
Moore ER, et al. Ferroplasma acidiphilum gen. nov., sp. nov., an
acidophilic, autotrophic, ferrous- iron- oxidizing, cell- wall- lacking,
mesophilic member of the Ferroplasmaceae fam. nov., comprising
a distinct lineage of the Archaea. Int J Syst Evol Microbiol 2000;50
Pt 3:997–1006.
45. Reichenbach H, Order V. Myxococcales Tchan, Pochon and Prévot
1948, 398AL. In: Brenner DJ, Krieg NR, Staley JT and Garrity GM
(eds). Bergey’s Manual of Systematic Bacteriology, 2nd edn, vol. 2,
part C. New York: Springer; 2005. pp. 1059–1072.
46. Garcia RO, Reichenbach H, Ring MW, Müller R. Phaselicystis flava
gen. nov., sp. nov., an arachidonic acid- containing soil myxobac-
terium, and the description of Phaselicystidaceae fam. nov. Int J
Syst Evol Microbiol 2009;59:1524–1530.
47. Kevbrin V, Boltyanskaya Y, Zhilina T, Kolganova T, Lavrentjeva E,
et al. Proteinivorax tanatarense gen. nov., sp. nov., an anaerobic,
haloalkaliphilic, proteolytic bacterium isolated from a decaying
algal bloom, and proposal of Proteinivoraceae fam. nov. Extremo-
philes 2013;17:747–756.
48. Choi EJ, Beatty DS, Paul LA, Fenical W, Jensen PR. Mooreia
alkaloidigena gen. nov., sp. nov. and Catalinimonas alkaloidigena
gen. nov., sp. nov., alkaloid- producing marine bacteria in the
proposed families Mooreiaceae fam. nov. and Catalimonadaceae
fam. nov. in the phylum Bacteroidetes. Int J Syst Evol Microbiol
2013;63:1219–1228.
49. Koval SF, Williams HN, Stine OC. Reclassification of Bacterio-
vorax marinus as Halobacteriovorax marinus gen. nov., comb. nov.
and Bacteriovorax litoralis as Halobacteriovorax litoralis comb.
nov.; description of Halobacteriovoraceae fam. nov. in the class
Deltaproteobacteria. Int J Syst Evol Microbiol 2015;65:593–597.
50. Krishnan R, Lang E, Midha S, Patil PB, Rameshkumar N. Isolation
and characterization of a novel 1- aminocyclopropane- 1- carboxy
late (ACC) deaminase producing plant growth promoting marine
Gammaproteobacteria from crops grown in brackish environ-
ments. Proposal for Pokkaliibacter plantistimulans gen. nov., sp.
nov., Balneatrichaceae fam. nov. in the order Oceanospirillales and
an emended description of the genus Balneatrix. Syst Appl Micro-
biol 2018;41:570–580.
51. Judicial Commission of the International Committee on Bacte-
riological Nomenclature. Conservation of the family name
Enterobacteriaceae, of the name of the type genus, and designa-
tion of the type species. Opinion No. 15. Int Bull Bacteriol Nomen
Taxon 1958;8:73–74.
52. Parte AC, Sardà Carbasse J, Meier- Koltho JP, Reimer LC,
Göker M. List of Prokaryotic names with Standing in Nomen-
clature (LPSN) moves to the DSMZ. Int J Syst Evol Microbiol
2020;70:5607–5612.
53. Oren A, Vandamme P, Schink B. Notes on the use of Greek word
roots in genus and species names of prokaryotes. Int J Syst Evol
Microbiol 2016;66:2129–2140.
54. Silva PC. Names of Classes and Families of Living Algae with
Special Reference to Their Use in the Index Nominum Genericorum
(Plantarum). Utrecht: Bohn, Scheltema & Holkema; 1980.
55. Bowman JP, Family V. Methylocystaceae fam. nov. In: Brenner
DJ, Krieg NR, Staley JT and Garrity GM (eds). Bergey’s Manual
of Systematic Bacteriology, 2nd edn, vol. 2, part C. New York:
Springer; 2005. pp. 411–413.
56. Oren A, Arahal DR, Rosselló-Móra R, Sutclie IC, Moore ERB.
Emendation of General Consideration 5 and Rules 18a, 24a and
30 of the International Code of Nomenclature of Prokaryotes to
resolve the status of the Cyanobacteria in the prokaryotic nomen-
clature. Int J Syst Evol Microbiol 2021;71:4939. ;
57. Mitra AK, Pandey DC. On a new genus of the blue- green alga
Chlorogloeopsis with remarks on the production of heterocysts in
the alga. Phykos 1967;5:106–114.
58. Komárek J, Kaštovský J, Mareš J, Johansen JR. Taxonomic clas-
sification of cyanoprokaryotes (cyanobacterial genera) 2014,
using a polyphasic approach. Preslia 2014;86:295–335.
59. Boden R, Oren A. Proposal to designate Methylothermus subter-
raneus Hirayama et al. 2011 as the type species of the genus
Methylothermus. Request for an Opinion. Int J Syst Evol Microbiol
2017;67:3685.
60. Hirayama H, Suzuki Y, Abe M, Miyazaki M, Makita H, etal. Methylo-
thermus subterraneus sp. nov., a moderately thermophilic metha-
notroph isolated from a terrestrial subsurface hot aquifer. Int J
Syst Evol Microbiol 2011;61:2646–2653. ;
61. Tsubota J, Eshinimaev Bt, Khmelenina VN, Trotsenko YA. Methy-
lothermus thermalis gen. nov., sp. nov., a novel moderately ther-
mophilic obligate methanotroph from a hot spring in Japan. Int J
Syst Evol Microbiol 2005;55:1877–1884.
62. Arahal DR. Opinions 97, 98 and 99. Int J Syst Evol Microbiol
2020;70:1439–1440.
63. Hirayama H, Abe M, Miyazaki M, Nunoura T, Furushima Y, et al.
Methylomarinovum caldicuralii gen. nov., sp. nov., a moderately
thermophilic methanotroph isolated from a shallow submarine
hydrothermal system, and proposal of the family Methylother-
maceae fam. nov. Int J Syst Evol Microbiol 2014;64:989–999.
64. Tindall BJ. On the nomenclatural types of Methylothermus ther-
malis Tsubota et al. 2005, Methylothermus Tsubota et al. 2005
and Methylothermaceae Hirayama et al. 2014, their status under
the International Code of Nomenclature of Prokaryotes and
valid publication of the names Methylothermus gen. nov., Methy-
lothermus subterraneus Hirayama et al. and Methylothermaceae
Hirayama et al. Int J Syst Evol Microbiol 2019;69:1890–1891.
65. Oren A. Proposal to correct the generic name Flaviaesturari-
ibacter Kang, Chun, Seo, Kim and Jahng 2015, 2212 to Flavaes-
tuariibacter. Request for an Opinion. Int J Syst Evol Microbiol
2017;67:3686.
66. Kang JY, Chun J, Seo J- W, Kim CH, Jahng KY. Flaviaestur-
ariibacter amylovorans gen. nov., sp. nov., a starch- hydrolysing
bacterium, isolated from estuarine water. Int J Syst Evol Microbiol
2015;65:2209–2214.
67. Oren A, Garrity GM. Notification that new names of prokaryotes,
new combinations and new taxonomic opinions have appeared
in volume 65, part 7, of the IJSEM. Int J Syst Evol Microbiol
2015;65:3233–3234.
68. Pascual J, Foesel BU, Geppert A, Huber KJ, Overmann J. Flavi-
aesturariibacter luteus sp. nov., isolated from an agricultural
20
Arahal etal., Int. J. Syst. Evol. Microbiol. 2022;72:005481
floodplain soil, and emended description of the genus Flaviaes-
turariibacter. Int J Syst Evol Microbiol 2017;67:1727–1734. ;
69. Okiria J, Lee J- J, Park S- J, Lee Y- H, Lee S- Y, etal. Flaviaesturari-
ibacter terrae sp. nov., isolated from mountain soil. Int J Syst Evol
Microbiol 2017;67:2660–2664. ;
70. Gupta RS, Patel S, Saini N, Chen S. Robust demarcation of 17
distinct Bacillus species clades, proposed as novel Bacillaceae
genera, by phylogenomics and comparative genomic analyses:
description of Robertmurraya kyonggiensis sp. nov. and proposal
for an emended genus Bacillus limiting it only to the members of
the Subtilis and Cereus clades of species. Int J Syst Evol Microbiol
2020;70:5753–5798.
71. Oren A, Garrity GM. Notification that new names of prokaryotes,
new combinations, and new taxonomic opinions have appeared
in volume 70, part 11 of the IJSEM. Int J Syst Evol Microbiol
2021;71:4645.
72. Cohn F. Untersuchungen über Bacterien II. Beiträge zur Biologie
der Pflanzen 1875;1:141–207.
73. Chaplin AV, Sokolova SR, Shcherbakova VA, Suzina NE,
Kochetkova TO, et al. Hydrogeniiclostidium mannosilyticum gen.
nov., sp. nov. isolated from human faeces. Int J Syst Evol Microbiol
2020;70:1210–1216.
74. Oren A, Garrity GM. Notification that new names of prokaryotes,
new combinations, and new taxonomic opinions have appeared
in volume 70, part 2 of the IJSEM. Int J Syst Evol Microbiol
2020;70:2967–2971.
75. Oren A. Proposal to designate the order Actinomycetales
Buchanan 1917, 162 (Approved Lists 1980) as the nomenclatural
type of the class Actinobacteria. Request for an Opinion. Int J Syst
Evol Microbiol 2017;67:3687–3688.
76. Buchanan RE. Studies in the nomenclature and classification of
the bacteria: II. The primary subdivisions of the Schizomycetes. J
Bacteriol 1917;2:155–164.
77. Krassilnikov NA. Opredelitelv Bakterii i Actinomicetov. Moscow:
Akademii Nauk SSSR; 1949.
78. Salam N, Jiao JY, Zhang XT, Li WJ. Update on the classification of
higher ranks in the phylum Actinobacteria Int J Syst Evol Microbiol
2020;70:1331–1355.
79. Tindall BJ. Names above the rank of genus; the radical approach.
Int J Syst Evol Microbiol 2019;69:1833–1834.
80. Harz CO. Actinomyces bovis, ein neuer Schimmel in den Geweben
des Rindes. Deutsche Zeitschrift für Thiermedizin 1877;5:125–140.
81. Tindall BJ. Names at the rank of class, subclass and order,
their typification and current status: supplementary informa-
tion to opinion 79. Judicial Commission of the International
Committee on Systematics of Prokaryotes. Int J Syst Evol Micro-
biol 2014;64:3599–3602.
82. Euzéby JP, Tindall BJ. Nomenclatural type of orders: corrections
necessary according to Rules 15 and 21a of the Bacteriological
Code (1990 Revision), and designation of appropriate nomenclat-
ural types of classes and subclasses. request for an opinion. Int J
Syst Evol Microbiol 2001;51:725–727.
83. Huber H, Stetter KO. Class I Deferribacteres class. nov. In: Boone
DR, Castenholz RW and Garrity GM (eds). Bergey’s Manual of
Systematic Bacteriology, 2nd edn, vol. 1. New York: Springer;
2001. pp. 465–471.
84. List Editor. Validation list no.85. Int J Syst Evol Microbiol
2002;52:685–690.
85. Oren A, Garrity GM. Valid publication of the names of forty- two
phyla of prokaryotes. Int J Syst Evol Microbiol 2021;71:5056.
86. Wong VK, Turmezei TD, Weston VC. Actinomycosis. BMJ
2011;343:d6099.
87. Oren A. Correction of the name Amycolatopsis albidoflavus to
Amycolatopsis albidiflava corrig. Request for an Opinion. Int J Syst
Evol Microbiol 2017;67:4284.
88. Lee SD, Hah YC. Amycolatopsis albidoflavus sp. nov. Int J Syst Evol
Microbiol 2001;51:645–650.
89. List Editor. Notification that new names and new combinations
have appeared in volume 50, part 2, of the IJSEM. Int J Syst Evol
Microbiol 2001;51:795–796.
90. Brenner DJ, Steigerwalt AG, Miklos GV, Fanning GR. Deoxyribo-
nucleic Acid relatedness among Erwiniae and other Enterobacte-
riaceae: the Soft- Rot organisms (Genus Pectobacterium Waldee).
Int J Syst Bacteriol 1973;23:205–216.
91. Moore RL, Weiner RM, Gebers R. Notes: Genus Hyphomonas
Pongratz 1957 nom. rev. emend., Hyphomonas polymorpha
Pongratz 1957 nom. rev. emend., and Hyphomonas neptunium
(Leifson 1964) comb. nov. emend. (Hyphomicrobium neptunium).
Int J Syst Bacteriol 1984;34:71–73.
92. Witt D, Stackebrandt E. Unification of the Genera Streptoverticillum
and Streptomyces, and Amendation of Streptomyces Waksman
and Henrici 1943, 339AL. Syst Appl Microbiol 1990;13:361–371. ;
93. Moshtaghi Nikou M, Ramezani M, Harirchi S, Makzoom S,
Amoozegar MA, et al. Salinifilum gen. nov., with description of
Salinifilum proteinilyticum sp. nov., an extremely halophilic actin-
omycete isolated from Meighan wetland, Iran, and reclas-
sification of Saccharopolyspora aidingensis as Salinifilum
aidingensis comb. nov. and Saccharopolyspora ghardaiensis
as Salinifilum ghardaiensis comb. nov. Int J Syst Evol Microbiol
2017;67:4221–4227.
94. Commission J. Rejection of Clostridium putrificum and conser-
vation of Clostridium botulinum and Clostridium sporogenes -
opinion 69. Int J Syst Bacteriol 1999;49:339.
95. Reddish GF, Rettger LF. Clostridium putrificum (B. putrificus Bien-
stock), a distinct species. J Bacteriol 1922;7:505–510.
96. Bergey DH, Harrison FC, Breed RS, Hammer BW, Huntoon FM.
Bergey’s Manual of Determinative Bacteriology. 1st edn. Baltimore:
Williams & Wilkins Co; 1923.
97. Dobritsa AP, Kutumbaka KK, Samadpour M. Reclassification
of Eubacterium combesii and discrepancies in the nomencla-
ture of botulinum neurotoxin- producing clostridia: Challenging
Opinion 69. Request for an Opinion. Int J Syst Evol Microbiol
2018;68:3068–3075.
98. Whitman WB, Bull CT, Busse HJ, Fournier PE, Oren A, et al.
Request for revision of the Statutes of the International
Committee on Systematics of Prokaryotes. Int J Syst Evol Micro-
biol 2019;69:584–593.
99. Olsen I, Johnson JL, Moore LVH, Moore WEC. Rejection of
Clostridium putrificum and conservation of Clostridium botulinum
and Clostridium sporogenes: request for an opinion. Int J Syst
Bacteriol 1995;45:414.
100. Williams JE. Proposal to reject the new Combination Yersinia
pseudotuberculosis subsp. pestis for Violation of the First Prin-
ciple of the International Code of Nomenclature of Bacteria:
Request for an Opinion. Int J Syst Bacteriol 1984;34:268–269.
101. Commission J. Opinion 60: Rejection of the Name Yersinia
pseudotuberculosis subsp. pestis (van Loghem) Bercovier et al.
1981 and conservation of the name Yersinia pestis (Lehmann
and Neumann) van Loghem 1944 for the plague bacillus: Judi-
cial Commission of the International Committee on Systematic
Bacteriology. Int J Syst Bacteriol 1985;35:540.
102. Balish M, Bertaccini A, Blanchard A, Brown D, Browning G, et al.
Recommended rejection of the names Malacoplasma gen. nov.,
Mesomycoplasma gen. nov., Metamycoplasma gen. nov., Meta-
mycoplasmataceae fam. nov., Mycoplasmoidaceae fam. nov.,
Mycoplasmoidales ord. nov., Mycoplasmoides gen. nov., Mycoplas-
mopsis gen. nov. [Gupta, Sawnani, Adeolu, Alnajar and Oren 2018]
and all proposed species comb. nov. placed therein. Int J Syst Evol
Microbiol 2019;69:3650–3653.
103. Gupta RS, Sawnani S, Adeolu M, Alnajar S, Oren A. Phyloge-
netic framework for the phylum Tenericutes based on genome
sequence data: proposal for the creation of a new order Myco-
plasmoidales ord. nov., containing two new families Mycoplas-
moidaceae fam. nov. and Metamycoplasmataceae fam. nov.
harbouring Eperythrozoon, Ureaplasma and five novel genera.
Antonie Van Leeuwenhoek 2018;111:1583–1630.
21
Arahal etal., Int. J. Syst. Evol. Microbiol. 2022;72:005481
104. Oren A, Garrity GM. List of new names and new combinations
previously eectively, but not validly, published. Int J Syst Evol
Microbiol 2018;68:3379–3393.
105. Gupta RS, Oren A. Necessity and rationale for the proposed
name changes in the classification of Mollicutes species. Reply
to: “Recommended rejection of the names Malacoplasma gen.
nov., Mesomycoplasma gen. nov., Metamycoplasma gen. nov.,
Metamycoplasmataceae fam. nov., Mycoplasmoidaceae fam. nov.,
Mycoplasmoidales ord. nov., Mycoplasmoides gen. nov., Mycoplas-
mopsis gen. nov. [Gupta, Sawnani, Adeolu, Alnajar and Oren 2018]
and all proposed species comb. nov. placed therein”, by M. Balish
et al. (Int J Syst Evol Microbiol, 2019;69:3650- 3653). Int J Syst Evol
Microbiol 2020;70:1431–1438.
106. Sutclie IC, Arahal DR, Göker M, Oren A. ICSP response to
“Science depends on nomenclature, but nomenclature is not
science.” Nat Rev Microbiol 2022;20:249–250.
107. Oren A, Garrity GM. The status of the Notes in the Interna-
tional Code of Nomenclature of Prokaryotes: proposal to
emend General Consideration 6. Int J Syst Evol Microbiol
2016;66:3305–3306.
108. Tindall BJ. Misunderstanding the Bacteriological Code. Int J Syst
Bacteriol 1999;49 Pt 3:1313–1316.
109. Tindall BJ. An analysis of the term “standing in nomenclature”, as
used in the International Code of Nomenclature of Prokaryotes.
Int J Syst Evol Microbiol 2019;69:2166–2168.
110. Buchanan RE, St John- Brooks R, Breed RS. International Bacte-
riological Code of Nomenclature. J Bacteriol 1948;55:287–306.
111. Qu P- H, Li Y, Salam N, Chen S- Y, Liu L, etal. Allofrancisella inopi-
nata gen. nov., sp. nov. and Allofrancisella frigidaquae sp. nov.,
isolated from water- cooling systems, and transfer of Franci-
sella guangzhouensis Qu et al. 2013 to the new genus as Allo-
francisella guangzhouensis comb. nov. Int J Syst Evol Microbiol
2016;66:4832–4838.
112. Tortoli E, Brown- Elliott BA, Chalmers JD, Cirillo DM, Daley CL,
etal. Same meat, dierent gravy: ignore the new names of myco-
bacteria. Eur Respir J 2019;54:1900795.
113. On SLW, Miller WG, Biggs PJ, Cornelius AJ, Vandamme P. A crit-
ical rebuttal of the proposed division of the genus Arcobacter into
six genera using comparative genomic, phylogenetic, and pheno-
typic criteria. Syst Appl Microbiol 2020;43:126108.
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