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 Sulfuricellales Watanabe et al. 2015 [monotypic]
           Family Sulfuricellaceae Watanabe et al. 2015
             1 Genus Sulfuricella Kojima and Fukui 2010
             2 Genus Sulfuriferula Watanabe et al. 2015
             3 Genus Sulfurirhabdus Watanabe et al. 2016