Natura - nature
   actualia - actual entities
     Mundus Plinius - physical world
       naturalia - natural bodies
         [crown] Clade Biota Wagner 2004 [Wiemann, de Queiroz, Rowe, Planavsky, Anderson, Gogarten, Turner & Gauthier 2020]
           Domain Bacteria Woese et al. 1990 [paraphyletic?]
             Superphylum Terrabacteria Battistuzzi et al. 2004
               Phylum Cyanobacteria (ex Stanier 1974) Cavalier-Smith 2002 - cyanobacteria
                 Class "Cyanobacteria" Cavalier-Smith, 2002
                   Subclass Synechococcophycideae
                     Order Synechococcalesᵀ
                       Family Synechococcaceae Komárek & Anagnostidis (1995)
                         Genus Synechococcusᵀ C. Nägeli (1849)
                           ?Synechococcus arcuatus Copel. (1936)
                             1 ?Synechococcus arcuatus var. calcicolus Fjerdingstad (1965)