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 Burkholderiales Garrity et al. 2006
                     Family Comamonadaceae Willems et al. 1991
                       Genus Hydrogenophaga Willems et al. 1989
                         1 Hydrogenophaga atypica Kämpfer et al. 2005
                         2 Hydrogenophaga bisanensis Yoon et al. 2008
                         3 Hydrogenophaga caeni Chung et al. 2007
                         4 Hydrogenophaga defluvii Kämpfer et al. 2005
                         5 Hydrogenophaga flava (Niklewski 1910) Willems et al. 1989
                         6 Hydrogenophaga intermedia Contzen et al. 2001
                         7 Hydrogenophaga palleronii (Davis 1970) Willems et al. 1989
                         8 Hydrogenophaga pseudoflava (Auling et al. 1978) Willems et al. 1989
                         9 Hydrogenophaga taeniospiralis (Lalucat et al. 1982) Willems et al. 1989