Domain Bacteria Woese et al. 1990
   Phylum Proteobacteria Garrity and Holt 2001 see Phylum Proteobacteria Garrity et al. 2005
     Class "Gammaproteobacteria" nom. inval. see Class Gammaproteobacteria Garrity et al. 2005
       Order "Thiotrichales" see Order Thiotrichales Garrity et al. 2005
         Family "Thiotrichaceae" see Family Thiotrichaceae Garrity et al. 2005
           Genus Achromatium Schewiakoff 1893 (Approved Lists 1980)
           Genus Beggiatoa Trevisan 1842 (Approved Lists 1980)
           Genus Leucothrix Oersted 1844 (Approved Lists 1980)
           Genus Macromonas Utermöhl and Koppe 1924 (Approved Lists 1980)
           Genus Thiobacterium (ex Janke 1924) La Riviere and Kuenen 1989
           Genus Thiomargarita Schulz et al. 1999
           Genus Thioploca Lauterborn 1907 (Approved Lists 1980)
           Genus Thiospira Visloukh 1914 (Approved Lists 1980)
           1 Genus Thiothrix Winogradsky 1888 (Approved Lists 1980)