The International Code of Nomenclature of Prokaryotes (ICNP) is the governing set of rules and recommendations for the scientific naming of prokaryotic organisms, i.e., bacteria and archaea. It establishes standards for the formation, publication, and priority of taxonomic names, ensuring worldwide consistency and stability in microbial nomenclature.
Authority and Administration
The ICNP is maintained by the International Committee on Systematics of Prokaryotes (ICSP), an independent body that operates under the auspices of the International Union of Microbiological Societies (IUMS). The ICSP reviews proposals for amendments, publishes revisions, and oversees the implementation of the Code.
Historical Development
- 1975 – The first formal code, titled the International Code of Nomenclature of Bacteria, was adopted at the International Botanical Congress.
- 1980 – The “Approved Lists of Bacterial Names” were published, establishing a baseline of validly published names.
- 1990 – The code was revised to accommodate new insights from molecular systematics.
- 2001 – The term “Bacteria” was replaced by “Prokaryotes” to reflect the inclusion of archaea, and the code was renamed accordingly.
- 2008 – Further amendments addressed electronic publication and the deposition of type strains.
- 2019 – The latest major revision clarified rules on the naming of uncultured taxa and introduced provisions for genome‑based typification.
Key Principles
- Priority – The earliest validly published name for a taxon has precedence, unless conserved or rejected by formal action.
- Effective Publication – A name must be published in a recognized scientific outlet (e.g., the International Journal of Systematic and Evolutionary Microbiology or other approved journals) and meet specific formatting criteria.
- Typification – Each taxon at the rank of species must be linked to a type strain, which must be deposited in at least two publicly accessible culture collections in different countries.
- Binomial Nomenclature – Species names consist of a genus name (capitalized) followed by a specific epithet (lowercase), both italicized (e.g., Escherichia coli).
- Ranks – The Code officially recognizes the ranks of genus, species, subspecies, family, order, class, phylum, and domain.
Publication and Validation
- Valid publication of a new name requires:
- A description or diagnosis published in an approved venue.
- Designation of a type strain.
- Inclusion of the name in the Validation Lists issued by the ICSP, which appear in the International Journal of Systematic and Evolutionary Microbiology.
- Electronic-only publications are permissible, provided they meet the Code’s criteria for effective publication.
Relation to Other Nomenclatural Codes
The ICNP operates alongside other biological nomenclature codes, such as the International Code of Nomenclature for algae, fungi and plants (ICN) and the International Code of Zoological Nomenclature (ICZN). While the ICNP is distinct in its focus on prokaryotes, there is coordination to avoid homonymy across the different codes.
Current Status
The most recent edition of the ICNP was published in 2019 and is accessible through the ICSP website and the International Journal of Systematic and Evolutionary Microbiology. Ongoing revisions are processed through proposals submitted to the ICSP, which are evaluated at regular meetings and via public commentary.
References
- International Committee on Systematics of Prokaryotes (ICSP). International Code of Nomenclature of Prokaryotes (2019 edition).
- Oren, A., & Garrity, G. (2020). "The International Code of Nomenclature of Prokaryotes: A Critical Overview." International Journal of Systematic and Evolutionary Microbiology, 70(5), 2713‑2722.
- Murray, R. G. E., & Stackebrandt, E. (1995). The Prokaryotes: A Handbook on the Biology of Bacteria. Springer.
