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?]
             Superphylum "Proteobacteria" Craig et al. 2010
               Phylum "Betaproteobacteria" Garrity et al., 2006 [monotypic]
                 Class Betaproteobacteriaᵀ Garrity et al. 2006
                   Order Hydrogenophilales Garrity et al. 2006 [monotypic]
                     Family Hydrogenophilaceaeᵀ Garrity et al. 2006
                       Genus Hydrogenophilusᵀ Hayashi et al. 1999
                         1 Hydrogenophilus thermoluteolusᵀ Hayashi et al. 1999
                         2 Hydrogenophilus hirschii Stöhr et al. 2001
                         3 Hydrogenophilus islandicus Vésteinsdóttir et al. 2011