Natura - nature
   actualia - actual entities
     Mundus Plinius - physical world
       naturalia - natural bodies
         Clade Biota Wagner 2004 [Wiemann, de Queiroz, Rowe, Planavsky, Anderson, Gogarten, Turner & Gauthier 2020]
           Domain Bacteria Woese et al. 2024
             Kingdom Pseudomonadati (Gibbons and Murray 1978) Oren and Göker 2024
               Phylum Pseudomonadotaᵀ Garrity et al. 2021
                 1 Class Acidithiobacillia Williams and Kelly 2013 [monotypic]
                 2 Class Alphaproteobacteria Garrity et al. 2006
                 3 Class Betaproteobacteria Garrity et al. 2006
                 4 Class Deltaproteobacteria Kuever et al. 2006
                 5 Class Epsilonproteobacteria Garrity et al. 2006
                 6 Class Gammaproteobacteriaᵀ Garrity et al. 2005
                 7 Class Hydrogenophilia Boden et al. 2022
                 8 Class Oligoflexia Nakai et al. 2014