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 Burkholderiaceaeᵀ Garrity et al. 2006
                       Genus Polynucleobacter Heckmann and Schmidt 1987
                         1 Polynucleobacter necessariusᵀ Heckmann and Schmidt 1987
                         2 Polynucleobacter cosmopolitanus Hahn et al. 2010
                         3 Polynucleobacter acidiphobus Hahn et al. 2011
                         4 Polynucleobacter rarus Hahn et al. 2011
                         5 Polynucleobacter difficilis Hahn et al. 2012