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 "Procabacteriales" Garrity et al., 2003 [monotypic]
                     Family "Procabacteriaceae"ᵀ Garrity et al., 2003 [monotypic]
                       1 Candidatus "Procabacter"ᵀ Horn et al. 2002 [monotypic]