Natura - nature
   actualia - actual entities
     Mundus Plinius - physical world
       naturalia - natural bodies
         Clade Biota Wagner 2004 [Wiemann, de Queiroz, Rowe, Planavsky, Anderson, Gogarten, Turner & Gauthier 2020]
           Domain Bacteria Woese et al. 2024
             Kingdom Pseudomonadati (Gibbons and Murray 1978) Oren and Göker 2024
               Phylum Pseudomonadotaᵀ Garrity et al. 2021
                 Class Alphaproteobacteria Garrity et al. 2006
                   Order Hyphomicrobiales Douglas 1957 (Approved Lists 1980)
                     Family Nitrobacteraceae corrig. Buchanan 1917 (Approved Lists 1980)
                       01 Genus Afipia Brenner et al. 1992
                       02 Genus Astrobacterium Potokina et al. 2026
                       03 Genus Blastobacter Zavarzin 1961 (Approved Lists 1980)
                       04 Genus Bradyrhizobium Jordan 1982
                       05 Genus Nitrobacterᵀ Winogradsky 1892 (Approved Lists 1980) nom. cons.
                       06 Genus Pseudolabrys Kämpfer et al. 2006 [monotypic]
                       07 Genus Pseudorhodoplanes Tirandaz et al. 2015
                       08 Genus Rhodoplanes Hiraishi and Ueda 1994
                       09 Genus Rhodopseudomonas Czurda and Maresch 1937 (Approved Lists 1980) nom. cons.
                       10 Genus Rugositalea Chung et al. 2026
                       11 Genus Tardiphaga De Meyer et al. 2012
                       12 Genus Undibacter Jung et al. 2022
                       13 Genus Variibacter Kim et al. 2014
                       14 Genus "Metalliresistens" Noisangiam et al. 2010 nom. inval.