Natura - nature
   actualia - actual entities
     Mundus Plinius - physical world
       naturalia - natural bodies
         Clade Biota Wagner 2004 [Wiemann, de Queiroz, Rowe, Planavsky, Anderson, Gogarten, Turner & Gauthier 2020]
           Domain Bacteria Woese et al. 2024
             Kingdom Pseudomonadati (Gibbons and Murray 1978) Oren and Göker 2024
               Phylum Pseudomonadotaᵀ Garrity et al. 2021
                 Class Gammaproteobacteriaᵀ Garrity et al. 2005
                   Order Beggiatoales Buchanan 1957 (Approved Lists 1980)
                     Family Piscirickettsiaceae Fryer and Lannan 2005
                       01 Genus Cycloclasticus Dyksterhouse et al. 1995 [monotypic]
                       02 Genus Galenea Giovannelli et al. 2012 [monotypic]
                       03 Genus Hydrogenovibrio Nishihara et al. 1991 [monotypic]
                       04 Genus Methylophaga Janvier et al. 1985
                       05 Genus Piscirickettsiaᵀ Fryer et al. 1992 [monotypic]
                       06 Genus Sulfurivirga Takai et al. 2006 [monotypic]
                       07 Genus Thiomicrorhabdus Boden et al. 2017
                       08 Genus Thiomicrospira Kuenen and Veldkamp 1972 (Approved Lists 1980)
                       09 Genus Thiosulfatimonas Mochizuki et al. 2022
                       10 Genus Thiosulfativibrio Mochizuki et al. 2022