Cyanobacterium Rippka & Cohen-Bazire, 2022

Holotype species: Cyanobacterium stanieri R.Rippka & G.Cohen-Bazire

Publication details: Rippka & Cohen-Bazire, 2022: 7

Original publication and holotype designation: Oren, A., Mareš, J. & Rippka, R. (2022). Validation of the names Cyanobacterium and Cyanobacterium stanieri, and proposal of Cyanobacteriota phyl. nov. International Journal of Systematic and Evolutionary Microbiology 72(10): article 005528 [1-7], 1 fig., 1 table.

Description: Unicellular cyanobacteria that reproduce by transverse binary fission in a single plane. Cells are widely oval to rod-like curved. Cell width is 1.7–4.5 µm and cell length is 2.5–7 (rarely up to 12 µm). Morphologically similar to Synechococcus and Cyanobium but differing by larger mean cell dimensions and in the arrangement of the thylakoids which align in more or less parallel planes and pass throughout the entire cell.

Information contributed by: Original description and J. Komárek. The most recent alteration to this page was made on 2025-05-15 by M.D. Guiry.

Taxonomic status: This name is of an entity that is currently accepted taxonomically.

Gender: This genus name is currently treated as neuter.

Most recent taxonomic treatment adopted: Polyakova, E., Averina, S. & Pinevich, A. (2023). Geminocystis urbisnovae sp. nov. (Chroococcales, Cyanobacteria): polyphasic description complemented with a survey of the family Geminocystaceae. Algae 38(2): 93-110.

Comments: Unicellular; cells solitary or in groups, oval, shortly cylindrical or irregularly cylindrical with widely rounded ends, without or with very fine mucilaginous layers around the cells. Cells usually pale blue-green to olive-green, mainly containing phycocyanin, with homogeneous content or with fine, dispersed granules, probably nonmotile, not forming filamentous involution forms. Probably with chromatic adaptation (?). GC-content of the DNA = approx. 39-41 mol. percent. Photoheterotroph. Reproduction by simple binary transverse fission perpendicular to the long axis of the cell. Cells grow into the original size before the next division. The type species was described from culture and based on biochemical characteristics, but further picoplanktonic freshwater and marine species belong probably to this genus, which needs further study, particularly from the point of view of cytomorphology, life cycles, variation range of physiological and morphological characters, and ecology. The "Marine-cluster C of Synechococcus" with oceanic picoplanktonic species (Platt & al. 1983), Waterbury (1989), Newman and Carr (1990), Waterbury and others (1979)) belongs probably also to this genus.

Nomenclatural notes
The Cyanobacteriaceae Komárek & al. (2014: 315) is an invalid name as it was based on a then-invalid genus name, Cyanobacterium Rippka & Cohen-Bazire, 1983. Now placed in the Geminocystaceae (Tuji & al., 2021; Polyakova & al., 2023: 102). - (24 August 2023) - G.M. Guiry
Genus and type species validated in Oren & al. (2022: 7). - (28 November 2022) - Salvador Valenzuela Miranda

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Contributors
Some of the descriptions included in AlgaeBase were originally from the unpublished Encyclopedia of Algal Genera, organised in the 1990s by Dr Bruce Parker on behalf of the Phycological Society of America (PSA) and intended to be published in CD format. These AlgaeBase descriptions are now being continually updated, and each current contributor is identified above. The PSA and AlgaeBase warmly acknowledge the generosity of all past and present contributors and particularly the work of Dr Parker.

Descriptions of chrysophyte genera were subsequently published in J. Kristiansen & H.R. Preisig (eds.). 2001. Encyclopedia of Chrysophyte Genera. Bibliotheca Phycologica 110: 1-260.

Linking to this page: https://www.algaebase.org/search/genus/detail/?genus_id=43579

Citing AlgaeBase
Cite this record as:
M.D. Guiry in Guiry, M.D. & Guiry, G.M. 15 May 2025. AlgaeBase. World-wide electronic publication, National University of Ireland, Galway. https://www.algaebase.org; searched on 18 June 2025