Phylum Cyanobacteria Garcia-Pichel et al. (2020) see Phylum Cyanobacteriota Oren et al. 2022
   Class Cyanophyceae Hauck (1885) see Class Chroococcophyceae Hollerbach et al. 1953
     Order Chroococcales Ardissone (1887) see Order Chroococcales corrig. Ardissone 1887
       Family Pleurocapsaceae Geitler (1925) see Family Hyellaceae Borzì (1914)
         ?Genus Hydrococcus Kütz. (1833), nom. cons. prop. see Genus Hydrococcus Kützing 1833 nom. cons.