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 Nautiliales Miroshnichenko et al. 2004 [monotypic]
                   Family Nautiliaceaeᵀ Miroshnichenko et al. 2004
                     Genus Cetia Grosche et al. 2015
                     1 Genus Nautiliaᵀ Miroshnichenko et al. 2002
                     2 Genus Caminibacter Alain et al. 2002
                     3 Genus Lebetimonas Takai et al. 2005 [monotypic]
                     4 Genus Nitratifractor Nakagawa et al. 2005 [monotypic]
                     5 Genus Nitratiruptor Nakagawa et al. 2005 [monotypic]
                     6 Genus Thioreductor Nakagawa et al. 2005 [monotypic]