prokaryotes - bacteria see Domain Bacteria Woese et al. 1990 stat. inval.
   Domain "Bacteria" Woese et al. 1990 stat. inval. see Domain Bacteria Woese et al. 2024
     Phylum "Proteobacteria" Garrity et al. 2005 stat. inval. see Phylum Pseudomonadota Garrity et al. 2021
       Class Alphaproteobacteria Garrity et al. 2006
         Order Rhizobiales Kuykendall 2006 see Order Hyphomicrobiales Douglas 1957 (Approved Lists 1980)
           Family Brucellaceae Breed et al. 1957 (Approved Lists 1980) see Family Bartonellaceae Gieszczykiewicz 1939 (Approved Lists 1980)
             1 Genus Brucella Meyer and Shaw 1920 (Approved Lists 1980)
             2 Genus Crabtreella Xie and Yokota 2006 see Genus Shinella An et al. 2006
             3 Genus Daeguia Yoon et al. 2008
             4 Genus Falsochrobactrum Kämpfer et al. 2013
             5 Genus Mycoplana Gray and Thornton 1928 (Approved Lists 1980)
             6 Genus Ochrobactrum Holmes et al. 1988 see Genus Brucella Meyer and Shaw 1920 (Approved Lists 1980)
             7 Genus Paenochrobactrum Kämpfer et al. 2010
             8 Genus Pseudochrobactrum Kämpfer et al. 2006