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 "Spirochaetes" Garrity and Holt 2001 [monotypic]
               Class Spirochaetesᵀ Cavalier-Smith 2002 [monotypic]
                 Order Brachyspirales Gupta et al. 2014, sedis mutabilis [monotypic]
                   Family Brachyspiraceaeᵀ Paster 2012 [monotypic]
                     Genus Brachyspiraᵀ Hovind-Hougen et al. 1983
                       Brachyspira hyodysenteriae (Harris et al. 1972) Ochiai et al. 1998