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?]
             Phylum "Epsilonproteobacteria" Garrity et al., 2006
               Class Epsilonproteobacteriaᵀ Garrity et al. 2006
                 Order Campylobacterales Garrity et al. 2006
                   Family Campylobacteraceaeᵀ Vandamme and De Ley 1991
                     Genus Campylobacterᵀ Sebald and Véron 1963 (Approved Lists 1980)
                       Campylobacter fetus (Smith and Taylor 1919) Sebald and Véron 1963 (Approved Lists 1980)
                         1 Campylobacter fetus subsp. fetusᵀ (Smith and Taylor 1919) Véron and Chatelain 1973 (Approved Lists 1980)
                         2 Campylobacter fetus subsp. testudinum Fitzgerald et al. 2014
                         3 Campylobacter fetus subsp. venerealis (Florent 1959) Véron and Chatelain 1973 (Approved Lists 1980)