Natura - nature
   actualia - actual entities
     Mundus Plinius - physical world
       naturalia - natural bodies
         [crown] Clade Biota Wagner 2004 [Wiemann, de Queiroz, Rowe, Planavsky, Anderson, Gogarten, Turner & Gauthier 2020]
           Domain Bacteria Woese et al. 1990 [paraphyletic?]
             Phylum "Epsilonproteobacteria" Garrity et al., 2006
               Class Epsilonproteobacteriaᵀ Garrity et al. 2006
                 Order Campylobacterales Garrity et al. 2006
                   Family Helicobacteraceae Garrity et al. 2006
                     1 Genus Helicobacterᵀ Goodwin et al. 1989
                     2 Genus Sulfuricurvum Kodama and Watanabe 2004 [monotypic]
                     3 Genus Sulfurimonas Inagaki et al. 2003
                     4 Genus Sulfurovum Inagaki et al. 2004 [monotypic]
                     5 Genus Thiovulum Hinze 1913 (Approved Lists 1980) [monotypic]
                     6 Genus Wolinella Tanner et al. 1981 [monotypic]