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 Spirochaetales Buchanan 1917 (Approved Lists 1980)
           Family Spirochaetaceae Swellengrebel 1907 (Approved Lists 1980)
             1 Genus Clevelandina Bermudes et al. 1988
             2 Genus Diplocalyx (ex Gharagozlou 1968) Bermudes et al. 1988
             3 Genus Hollandina (ex To et al. 1978) Bermudes et al. 1988
             4 Genus Pillotina (ex Hollande and Gharagozlou 1967) Bermudes et al. 1988
             5 Genus Salinispira Ben Hania et al. 2015
             6 Genus Spirochaeta Ehrenberg 1835 (Approved Lists 1980)
             7 Genus Treponema Schaudinn 1905 (Approved Lists 1980)