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 "Gammaproteobacteria" Garrity et al., 2005 [monotypic]
                 Class Gammaproteobacteriaᵀ Garrity et al. 2005
                   Order Pasteurellales Garrity et al. 2005 [monotypic]
                     Family Pasteurellaceaeᵀ Pohl 1981
                       Genus Actinobacillus Brumpt 1910 (Approved Lists 1980)
                         Actinobacillus equuli (van Straaten 1918) Haupt 1934 (Approved Lists 1980)
                           Actinobacillus equuli subsp. equuliᵀ (van Straaten 1918) Christensen et al. 2002