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 Macromonas Utermöhl and Koppe 1924 (Approved Lists 1980)