prokaryotes - bacteria see Domain Bacteria Woese et al. 1990
   Domain "Bacteria" Woese et al. 1990
     Phylum "Proteobacteria" Garrity et al. 2005 see Superphylum Proteobacteria Craig et al. 2010
       Class Betaproteobacteria Garrity et al. 2006
         Order Nitrosomonadales Garrity et al. 2006
           Family Gallionellaceae Henrici and Johnson 1935 (Approved Lists 1980)
             1 Genus Ferriphaselus Kato et al. 2014, incertae sedis
             2 Genus Gallionella Ehrenberg 1838 (Approved Lists 1980)