procaryotes
   Domain Bacteria Woese et al. 1990 stat. inval. see Domain Bacteria Woese et al. 2024
     Phylum Spirochaetes Garrity and Holt 2001 nom. inval. [monotypic] see Phylum Spirochaetota Garrity and Holt 2021
       Class "Spirochaetes" "Garrity and Holt 2001" nom. nud. [monotypic] see Class Spirochaetes Cavalier-Smith 2002 nom. rej.
         Order Spirochaetales Buchanan 1917 (Approved Lists 1980)
           Family Leptospiraceae Hovind-Hougen 1979 (Approved Lists 1980)
             1 Genus Leptonema Hovind-Hougen 1983 nom. illeg.
             2 Genus Leptospira Noguchi 1917 (Approved Lists 1980)