Cyanobacterium (genus)

Cyanobacterium is a genus of cyanobacteria. Unusual for cyanobacteria, it is published under the International Code of Nomenclature of Prokaryotes. It became a validly published name in 2022.
It contains one validly-published species, the type species Cyanobacterium stanieri. There is an effectively published "Cyanobacterium aponinum".
GTDB splits Cyanobacterium stanieri into two species-sized clusters and reports three more unnamed species clusters in its understanding of Cyanobacterium. The "Cyanobacterium aponinum PCC 10605" RefSeq genome GCF_000317675.1 is assigned to different genus with a placeholder name, PCC-10605, under GTDB's version of Cyanobacteriaceae. GTDB's version of the Cyanobacteriaceae also includes Geminocystis and two more placeholder genera.