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
               1.1 Phylum "Alphaproteobacteria" Garrity et al., 2006 [monotypic]
               1.2.1 Phylum "Acidithiobacillia" [monotypic]
               1.2.2.1 Phylum "Gammaproteobacteria" Garrity et al., 2005 [monotypic]
               1.2.2.2.1 Candidate phylum Muproteobacteria (RIF23) Anantharaman et al. 2016
               1.2.2.2.2 Phylum "Betaproteobacteria" Garrity et al., 2006 [monotypic]
               2 Phylum "Zetaproteobacteria" Emerson et al., 2007 [monotypic]