Q1: The nomenclature of many species in Mollicutes has been changed recently. For example, Mycoplasma genitalium (LPSN link) was reclassified as Mycoplasmoides genitalium (LPSN link). Which one is the “correct name”? How do I choose?
A1: These two names are synonyms, both are validly published under the International Code of Nomenclature of Prokaryotes (ICNP). An author can choose his/her preferred name to use in publications.
“… controversies arise from species being proposed for placement in other genera, accompanied by the proposal and valid publication of new combinations. While such proposals are simply an expression of taxonomic freedom, the same taxonomic freedom allows others to prefer an older validly published name for the same species, thereby implying the position of the species in another genus. One of the most serious misunderstandings of the ICNP is the belief that, in a series of homotypic synonyms, the last validly published name must be treated as the correct name.”
Ad Hoc Committee on Mitigating Changes in Prokaryotic Nomenclature (CoMiCProN), ICSP
“… The vast majority of bacterial name changes are due to changes in taxonomic opinion. Even if these newer taxonomic opinions take the form of new bacterial names that are validly published and legitimate under the ICNP, this alone does not imply any formal obligation to adopt the more recently proposed names if their older counterparts are also validly published and legitimate, as it is usually the case.”
“… to mitigate bacterial name changes, it is important to inform agencies, databases, journal authors, reviewers, and editors that most bacterial name changes are not mandatory under the ICNP, even though they may be perceived as such.”
Clarification by Aharon Oren
Oren, A. On validly published names, correct names, and changes in the nomenclature of phyla and genera of prokaryotes: a guide for the perplexed. npj Biofilms Microbiomes 10, 20 (2024). https://doi.org/10.1038/s41522-024-00494-9
“… all the older names that were validly published in the past can still be used by authors who prefer the older nomenclature.”
List of Prokaryotic names with Standing in Nomenclature (LPSN)
“… a major misconception regarding the correct name is that, among a series of homotypic synonyms, the most recent validly published and legitimate name must be selected as the correct name.”
ICSP Subcommittee on the Taxonomy of Mollicutes
The new names proposed by Gupta et al. regarding the reclassification of Mycoplasma (Gupta et al. 2018) caused confusion. The Subcommittee recommended rejection of those names (Balish et al. 2019). However, the ICSP Judicial Opinion 122 denied the request, so names such as Malacoplasma, Mesomycoplasma, and Metamycoplasma are valid.
Due to the ICSP ruling, although the Subcommittee holds a similar position regarding other reclassifications proposed in (Gupta et al. 2019), a separate “Request for an Opinion” was not prepared.
Based on the discussion of this Subcommittee and attendees of the International Organization for Mycoplasmology (IOM) Congress, the majority opinion strongly preferred the original names (i.e., names such as Mycoplasma genitalium).
Q2: New species
Q2: How do I name a new species?
A2: Follow the minimal standards for descriptions of new species; see references.
Engage with the Mollicutes research community prior to publication of changes is strongly advised.
If further assistance is needed, please contact the subcommittee (member list).
Q3: Culture collections
Q3: Which culture collections accept depositions of Mollicutes strains?
A3: This list was reviewed in 2021; '*' indicates those with no charge for deposition, shipping fees apply