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 Bacteroidota Krieg et al. 2021
                 Class Bacteroidiaᵀ Krieg 2012 [monotypic]
                   Order Bacteroidalesᵀ Krieg 2012
                     Family Bacteroidaceaeᵀ Pribram 1933 (Approved Lists 1980)
                       Genus Bacteroidesᵀ Castellani and Chalmers 1919 (Approved Lists 1980)
                         Bacteroides fragilisᵀ (Veillon and Zuber 1898) Castellani and Chalmers 1919 (Approved Lists 1980)