Nomenclature of the cyanophyta/cyanobacteria/cyanoprokaryotes under the International Code of Nomenclature of Prokaryotes

Oren, Aharon; Tindall, Brian J.


Nomenclature of cyanophyta/cyanobacteria/cyanoprokaryotes has traditionally been governed by the International Code of Botanical Nomenclature (ICBN). However, while recognizing their prokaryotic nature, Stanier and colleagues proposed in 1978 that their nomenclature shall be governed by the provisions of the International Code of Nomenclature of Bacteria ('The Bacteriological Code', now: International Code of Nomenclature of Prokaryotes; ICNP). In the same year, the Judicial Commission of the International Committee on Systematic Bacteriology (ICSB) expressed the view that workers who believe blue-green algae to be bacteria are at liberty to use the Bacteriological Code for their nomenclature. Although this ruling was never formally endorsed by the ICSB, a dual nomenclature system emerged with species being named according to the provisions of either code, although the consequences are not evident to most scientists. Valid publication under the ICNP includes a formal act of registration/indexing, centralized in a single journal, the International Journal of Systematic and Evolutionary Microbiology (IJSEM), a concept currently not favored in botany, where few restrictions exist on the journal in which names may be validly published. Under the ICNP, description of a nomenclatural type of a species must include the designation of a living type strain, which should have been maintained in pure culture. Subcultures of this type strain must be deposited in at least two publicly accessible service collections located in different countries. Under the ICBN, type specimens of names of taxa must be preserved permanently and may not be living plants or cultures (although algal cultures preserved in a metabolically inactive state are acceptable as types). Neither the General Committee on Botanical Nomenclature (GCBN) nor the International Committee on Systematics of Prokaryotes (ICSP) can make claims to the nomenclature of cyanophyta/cyanobacteria exclusively. Solutions have therefore to be sought to make the two modes of nomenclature compatible without the need to establish a special 'Cyano-Code'. The ideal solution would develop a joint nomenclature and the use of identical methods for the description of species and designation of types. If this is not possible, an interim solution may be proposed. Many of the species within current 'botanical' genera are already represented by axenic cultures in culture collections. These can be used as the basis for an 'approved list of names of cyanobacteria' after all requirements for their description as species of Prokaryotes will have been met, and they could be designated type strains. However, these cultures are rarely, if ever, derived from the same material on which the botanical description was based. Amendments of the rules of the ICNP, to be approved by the ICSP, will be required to establish such a consensus nomenclature. A system of dual types associated with different circumscriptions may, however, lead to an undesirable divergence between the bacteriological and the botanical system. A committee consisting of representatives of the ICBN and the ICSP should be established to discuss nomenclatural problems resulting from the unique position of the cyanophyta/cyanobacteria/cyanoprokaryotes. Minimal standards should be established for the description of new genera and species of cyanobacteria under the ICNP in a way that will be acceptable to the botanical authorities as well. The ultimate goal is to achieve a consensus nomenclature acceptable both to the GCBN and the ICSP.


cyanobacteriacyanophytanomenclatureinternational code of nomenclature of prokaryotesinternational code of botanical nomenclature