prokaryotes - bacteria see Domain Bacteria Woese et al. 1990
   Domain "Bacteria" Woese et al. 1990
     Phylum "Spirochaetes" Garrity and Holt 2001 [monotypic]
       Class Spirochaetes Cavalier-Smith 2002
         Order Brachyspirales Gupta et al. 2014 [monotypic]
           Family Brachyspiraceae Paster 2012
             1 Genus Brachyspira Hovind-Hougen et al. 1983
             2 Genus Serpulina Stanton 1992 see Genus Brachyspira Hovind-Hougen et al. 1983