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 "Alphaproteobacteria" Garrity et al., 2006 [monotypic]
                 Class Alphaproteobacteriaᵀ Garrity et al. 2006
                   Order Rhizobiales Kuykendall 2006
                     Family Brucellaceae Breed et al. 1957 (Approved Lists 1980)
                       Genus Brucellaᵀ Meyer and Shaw 1920 (Approved Lists 1980)
                         1 Brucella ceti Foster et al. 2007
                         2 Brucella inopinata Scholz et al. 2010
                         3 Brucella melitensisᵀ (Hughes 1893) Meyer and Shaw 1920 (Approved Lists 1980)
                         4 Brucella microti Scholz et al. 2008
                         5 Brucella pinnipedialis Foster et al. 2007