[organisms] see Clade Biota Wagner 2004 [Wiemann, de Queiroz, Rowe, Planavsky, Anderson, Gogarten, Turner & Gauthier 2020]
   Domain Bacteria Woese et al. 1990
     Phylum "Proteobacteria" Garrity et al. 2005 see Superphylum Proteobacteria Craig et al. 2010
       Class Gammaproteobacteria Garrity et al. 2005
         Order Thiotrichales Garrity et al. 2005
           Family Piscirickettsiaceae Fryer and Lannan 2005
             1 Genus Piscirickettsia Fryer et al. 1992
             2 Genus Cycloclasticus Dyksterhouse et al. 1995
             3 Genus Hydrogenovibrio Nishihara et al. 1991
             4 Genus Methylophaga Janvier et al. 1985
             5 Genus Sulfurivirga Takai et al. 2006
             6 Genus Thioalkalimicrobium Sorokin et al. 2001
             7 Genus Thiomicrospira Kuenen and Veldkamp 1972 (Approved Lists 1980)