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
                       1 Brachyspira aalborgiᵀ Hovind-Hougen et al. 1983
                       2.1 Brachyspira alvinipulli Stanton et al. 1998
                       2.2 Brachyspira hyodysenteriae (Harris et al. 1972) Ochiai et al. 1998
                       2.3 Brachyspira innocens (Kinyon and Harris 1979) Ochiai et al. 1998
                       2.4 Brachyspira intermedia (Stanton et al. 1997) Hampson and La 2006
                       2.5 Brachyspira murdochii (Stanton et al. 1997) Hampson and La 2006
                       2.6 Brachyspira pilosicoli (Trott et al. 1996) Ochiai et al. 1998