Natura - nature
Ref: C. Linnaeus, 1748: 210
   actualia - actual entities
  Ref: A. Voltolini, 2006: 44 (note 19) [assumed position]
     Mundus Plinius - physical world
    Ref: C. Linnaeus, 1758: 5 [indirect position]; 24 Apr 2014.
       naturalia - natural bodies
      Ref: C. Linnaeus, 1758: 6 [implicit position]
         [crown] Clade Biota Wagner 2004 [Wiemann, de Queiroz, Rowe, Planavsky, Anderson, Gogarten, Turner & Gauthier 2020]
        Ref: J. Wiemann et al., 2020: [13] [validation] [inferred position]
           [Domain] Bacteria Woese et al. 1990 [paraphyletic?]
          Ref: J. Wiemann et al., 2020: [13] [inferred rank]
             Superphylum "Proteobacteria" Craig et al. 2010
            Ref: Craig et al., 2010
               Phylum "Betaproteobacteria" Garrity et al., 2006 [monotypic]
              Ref: K. Anantharaman et al., 2016: fig. 2 [inferred position]
                 Class Betaproteobacteriaᵀ Garrity et al. 2006
                Ref: L.A. Hug et al., 2016: fig. 1 [inferred position]
                   Order "Procabacteriales" Garrity et al., 2003 [monotypic]
                  Ref: J.P. Euzéby, 2016: [1 Sep 2017]
                     Family "Procabacteriaceae"ᵀ Garrity et al., 2003 [monotypic]
                    Ref: J.P. Euzéby, 2016: [5 Sep 2017]
                       1 Candidatus "Procabacter"ᵀ Horn et al. 2002 [monotypic]
                      Ref: G.M. Garrity et al., 2007: 147