[organisms] see Clade Biota Wagner 2004 [Wiemann, de Queiroz, Rowe, Planavsky, Anderson, Gogarten, Turner & Gauthier 2020]
   Domain Bacteria Woese et al. 1990 stat. inval. see Domain Bacteria Woese et al. 2024
     Phylum "Proteobacteria" Garrity et al. 2005 stat. inval. see Phylum Pseudomonadota Garrity et al. 2021
       Class Gammaproteobacteria Garrity et al. 2005
         Order Thiotrichales Garrity et al. 2005 nom. illeg. see Order Beggiatoales Buchanan 1957 (Approved Lists 1980)
           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 see Genus Thiomicrospira Kuenen and Veldkamp 1972 (Approved Lists 1980)
             7 Genus Thiomicrospira Kuenen and Veldkamp 1972 (Approved Lists 1980)