The ICSP is pleased to announce the publication of the 2022 revision of the International Code of Nomenclature of Prokaryotes

Following IJSEM’s new instructions for authors below, from 4 January 2023 the article types on our submission system, Editorial Manager will be: Research article, ICSP matters, List, Review, Editorial, Short Communication, Letter to the Editor.

Please note taxonomic descriptions and taxonomic notes have been removed as an article type, please submit these under the article type “Research Article”.

All ICSP related minutes, including subcommittee and JC minutes and Requests for an Opinion, should be submitted under the “ICSP Matters” article type.

Aims and scope

Published by the Microbiology Society and owned by the International Committee on Systematics of Prokaryotes (ICSP), a committee of the Bacteriology and Applied Microbiology Division of the International Union of Microbiological Societies, International Journal of Systematic and Evolutionary Microbiology is the leading forum for the publication of novel microbial taxa and the ICSP’s official journal of record for prokaryotic names.

The journal welcomes high-quality research on all aspects of microbial evolution, phylogenetics and systematics, encouraging submissions on all prokaryotes, yeasts, microfungi, protozoa and microalgae across the full breadth of systematics including:

  • Identification, characterisation and culture preservation
  • Microbial evolution and biodiversity
  • Molecular environmental work with strong taxonomic or evolutionary content
  • Nomenclature
  • Taxonomy and phylogenetics.

In addition to submitted work from researchers, the journal also publishes:

  • Notification Lists: new names of prokaryotes, new combinations, and new taxonomic opinions that have been published in the journal.
  • Official Validation Lists: names of new prokaryotes not published in the journal. For guidance, see section 'Valid publication of names published outside the journal' below.
  • Changes in Taxonomic Opinion: resulting from the creation of synonyms or emended descriptions to be made widely available to the public. The names that are to be used are those that are the ‘correct names’ (in the sense of Principle 6) in the opinion of the bacteriologist, with a given circumscription, position and rank. A particular name, circumscription, position and rank does not have to be adopted in all circumstances. Consequently, the List of Changes in Taxonomic Opinion must be considered as a service to bacteriology and it has no ‘official character’, other than providing a centralised point for registering/indexing such changes in a way that makes them easily accessible to the scientific community. Taxonomic opinions included in the List cannot be considered as validly published nor, in any other way, approved by the ICSP and its Judicial Commission. Scientists wishing to have changes in taxonomic opinion included in future lists should send a PDF file of the appropriate reprint to the journal.
  • Opinions of the Judicial Commission of the ICSP.
  • Minutes of ICSP subcommittees.

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Publication of new taxa

For all articles reporting novel taxa, please refer to the nomenclature guidelines below and pre-submission checklist.

Single strain species descriptions (SSSD) are discouraged. We also highly recommend that strains representing new taxa coming from the single isolation experiment/environmental sample are described in a single manuscript. For more information, please see Oren and Trujillo (2018), Avoiding “salami slicing” in publications describing new taxa.

Provide proof of deposit that viable cultures of any proposed archaeal or bacterial type strains have been deposited in two or more public culture collections in different countries with no restrictions on availability. If there are any Material Transfer Agreements associated with the certificates of deposit, please include this information during submission.

When describing a new taxon, the following must be included within a submission:

Introduction, this section should highlight details related to the ecology and other relevant aspects of the new taxon. In this section, previously published information relevant to the new taxon should be cited. Please do not include long lists of validly published names of species associated with a particular genus, although the type species should be highlighted. Instead, please cite the data at LPSN using the following reference: 

Parte et al. List of Prokaryotic names with Standing in Nomenclature (LPSN) moves to the DSMZ. Int J Syst Evol Microbiol 2020;70:5607-5612. DOI: 10.1099/ijsem.0.004332

Results and Discussion, it is expected that results of the new taxon are not only reported but also discussed citing appropriate literature. The description of new taxa (genus or species) should include its family classification when appropriate. This information should be provided in this part of the manuscript.

Key information about the new Taxon:

Genome sequences of the type strains of prokaryotes

Authors should include genome sequencing data with submissions of proposed novel prokaryotic taxa and the data should complement the discussed research. Genome sequences are of great value to the systematics of prokaryotes. In addition to improving the general understanding of the biology of microorganisms, they improve the identification of prokaryotic species, identification of functional characteristics useful for resolving taxonomic groups, and the resolution of the phylogeny of higher taxa. For more information on the use of genome data for the taxonomy of prokaryotes, please see Chun et al. (2018). General genomic information should include statistics such as N50, number of contigs, number of CDS, number of tRNAs, number of rRNAs, genome size and digital GC content. Overall genomic relatedness indices (OGRI) (Chun and Rainey, 2014) such as ANI and dDDH values should be used to highlight genomic differences between the new taxon and closely related type strains, especially at the species level. Phylogenetic analysis, especially those using genome information, must be included. In addition, other genomic information should be used to predict diagnostic phenotypes (e.g. secondary metabolism, metabolic pathways, pathogenicity, etc.) to support differentiation between closely related taxa or as part of the discussion of the unique characteristics of the proposed new taxon. For authors who cannot afford genome sequencing, the journal has collaborated with the World Data Center for Microorganisms which provides a route for strains to be sequenced for free. For more information please refer to Wu and Ma (2019).  If authors are unable to provide genome sequence data for any other reasons they should state why during the submission process and these will be considered by the Editor-in-Chief. All sequence data must be deposited in NCBI, EMBL-EBI or DDBJ to be available at INSDC (International Nucleotide Sequence Database Collaboration) and must be publicly available at submission. This is to ensure both the longevity of the data and to make sure that it is freely accessible.

16S rRNA gene sequencing

The almost complete 16S rRNA gene (>1400 nucleotides) should also be provided separately from the genome sequence. Independent 16S rRNA gene sequencing is useful to confirm the authenticity of the final genome assembly. This sequence must be deposited in a public repository (Genbank, NCBI, etc.) and accession numbers must be provided upon submission. 

Isolation, habitat and sample description

Precise locations may be detailed using geographical coordinates of latitude and longitude (e.g. 51°31'22.1"N, 0°06'54.5"W) or GPS data given to 6 decimal places (e.g. 51.522807, −0.115144). Isolation date should also be included. 

Morphology and Growth Conditions

Information about cultivation media used for growth should be provided. A description of the morphological characters that may be pertinent to its classification must be included. Authors may supply suitable photomicrographs (e.g. electron micrographs) as part of the description, but authors are encouraged to consider how informative these are.


Information of environmental factors that influence growth should be included as part of the physiological characterization. These include temperature and pH range, salinity and oxygen requirement. Other physiological/phenotypic tests relevant to the new taxon, especially those which are diagnostic and inferred from genome information are most welcomed. Standardized methods are preferred over miniature/commercial tests. Enzymatic activities recorded, especially those obtained with miniaturized kits, while useful, are strain variable and should not be included in the species description (protologue). Instead, they can be reported in the Results section.


It is recommended that chemotaxonomic markers are included as part of a new genus description. These markers may include fatty acid profiles, polar lipid composition, quinone types, polyamine patterns, and peptidoglycan type/composition as deemed appropriate. Chemotaxonomic markers for species descriptions are optional, especially for the description of species that belong to well represented genera (https://lpsn.dsmz.de/text/largest-genera). In this case, MALDI-TOF spectra comparisons with closely related type strains is preferred. In-silico chemotaxonomic markers inferred from the genome are welcomed. For a recent consideration of the appropriateness of chemotaxonomic tests, please see Vandamme and Sutcliffe (2021).

Species description (Protologue)

Recommendations for species description. This section refers to information describing the species, not the type strain, even when based on a single isolate. Please do not refer to the species using the type strain code. Antibiotic susceptibility is usually strain specific, therefore this information should not be included in the species description, but in the main text. Only major fatty acids should be included in this section, please avoid using numeric values as these are strain specific and do not correspond to the species.

Author statements

Please refer to our Prepare an article page for any author statements that may need to be included with your submission.

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Nomenclature guidelines

Valid publication of names of bacterial taxa

The Principles and Rules of nomenclature are published in the International Code of Nomenclature of Prokaryotes (2022 Revision).  In summary, the requirements for the valid publication of new names and combinations are as follows:

  1. The new name or combination must be published in the International Journal of Systematic and Evolutionary Microbiology. If published elsewhere, the new name or combination is not validly published until it is published in the IJSEM. The date of publication of the new name or combination is the date of publication in the IJSEM.
  2. New names must be formed in accordance with the rules of the Code. Guidelines for the formation of correct names can be found in:
  3. Assistance with names is often required from those with competence in Latin and Greek. Authors are encouraged to contact one of the journal's nomenclature reviewers, by emailing the journal at [email protected] for guidance prior to the submission of their manuscripts.
  4. The nomenclature of prokaryotes is not independent of virological, botanical and zoological nomenclature. When naming new taxa in the rank of genus or higher, due consideration is to be given to avoiding names which are regulated by the International Code of Virus Classification and Nomenclature, the International Code of Nomenclature for algae, fungi and plants, and the International Code of Zoological Nomenclature. For further information see Appendix 3 of the ICNP
    • For information on the treatment of cyanobacteria under the Code, see General Consideration 5, Rule 18a(3), Rule 24a and Rule 30(4).
  5. As required by Rule 27(2)a, a name should be clearly proposed as a new name or combination. New names are ordinarily proposed by an author appending the phrase 'species nova' (abbreviation: sp. nov.), 'genus novum' (abbreviation: gen. nov.), 'nomen novum' (abbreviation: nom. nov.), 'combinatio nova' (abbreviation: comb. nov.), or the like after the name or combination being proposed as new.
  6. As required by Rule 27(2)b, the derivation (etymology) of a new name (and if necessary of a new combination) must be given – see any recent issue of the journal for examples.
  7. As required by Rule 27(2)c, the name and etymology must be followed by a description of its properties or by a reference to a previously published description of the taxon. For novel combinations, the basonym and other synonyms should be listed.
  8. The nomenclatural type of the taxon must be designated. For species and subspecies, the type strain should be described and designated by the author's strain number as well as by the strain numbers under which it is held by at least two culture collections in TWO different countries from which the strain is available without restriction. For new combinations, the type strain must be cited. Culture Collections that are members of the World Federation of Culture Collections generally qualify. In cases of doubt, the Editors may be consulted.

Valid publication of names published outside the journal

For validation of new names published elsewhere, authors should submit a covering letter and a PDF of the published article(s) to [email protected]. The requirements for validation are identical to those for publication in the journal (i.e. authors must provide evidence that types are deposited in two recognised culture collections in two different countries).

Publication of names of unicellular eukaryotes

Please refer to the International Code of Nomenclature for algae, fungi and plants or to the International Code of Zoological Nomenclature, as applicable. Much of what is written above for bacteria is relevant to the description of new taxa of unicellular eukaryotes. In the case of fungi and microfungi, according to the rules of the International Code of Nomenclature for algae, fungi and plants, a Latin diagnosis of the new taxon may be included, but is no longer compulsory, and the journal requires that an etymology/description in English in a style like that for prokaryotes be given.

Designation of Neotype Strains

A neotype strain is a strain that replaces, by international agreement, a type strain which is no longer in existence. The neotype should possess the characteristics given in the original description; any deviations should be explained. A proposal of a neotype strain must be published in the journal together with a reference (or references) to the first description and name for the micro-organism, a description (or reference to a description) of the proposed neotype strain, and a record of the author's designation for the neotype strain and of at least two culture collections in different countries from which cultures of the strain are available. The neotype strain becomes established two years after the date of its publication in the journal, provided that there are no objections, which must be referred within the first year of the publication of the neotype to the Judicial Commission for consideration. A neotype strain should be proposed only after a careful search has shown that none of the strains on which the original description was based is extant. If an original strain is subsequently discovered, the matter should be referred immediately to the Judicial Commission.

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Indexing and metrics

The journal is indexed in AGRICOLA, Biological Abstracts, BIOSIS Previews, CAB Abstracts, CSA Illustrata, Chemical Abstracts, Current Contents–Life Sciences, EMBASE, MEDLINE, Info-Med, Science Citation Index, SciSearch, and SCOPUS, as well as on Google Scholar, ensuring maximum discoverability of your research.

Visit our Impact and metrics page to learn more about the metrics for International Journal of Systematic and Evolutionary Microbiology .

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Information for authors

For more information about submitting to International Journal of Systematic and Evolutionary Microbiology , please see our Article types, Prepare an article and Submission and peer review pages. 

International Journal of Systematic and Evolutionary Microbiology provides authors with the option to publish subscription (paywalled) articles free-of-charge, or Gold Open Access articles. Microbiology Society journals offer two routes for Gold Open Access publishing: Publish and Read and Article Processing Charges. More information can be found on our Open Access costs page.

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