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 Serpulina Stanton 1992] see Genus Brachyspira Hovind-Hougen et al. 1983
                       1 [Serpulina alvinipulli Stanton et al. 1998] see Brachyspira alvinipulli Stanton et al. 1998
                       2 [Serpulina hyodysenteriaeᵀ (Harris et al. 1972) Stanton 1992] see Brachyspira hyodysenteriae (Harris et al. 1972) Ochiai et al. 1998
                       3 [Serpulina innocens (Kinyon and Harris 1979) Stanton 1992] see Brachyspira innocens (Kinyon and Harris 1979) Ochiai et al. 1998
                       4 [Serpulina intermedia Stanton et al. 1997] see Brachyspira intermedia (Stanton et al. 1997) Hampson and La 2006
                       5 [Serpulina murdochii Stanton et al. 1997] see Brachyspira murdochii (Stanton et al. 1997) Hampson and La 2006
                       6 [Serpulina pilosicoli Trott et al. 1996] see Brachyspira pilosicoli (Trott et al. 1996) Ochiai et al. 1998