Natura - nature
   actualia - actual entities
     Mundus Plinius - physical world
       naturalia - natural bodies
         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 Spirochaetalesᵀ Buchanan 1917 (Approved Lists 1980), sedis mutabilis
                   Family Spirochaetaceaeᵀ Swellengrebel 1907 (Approved Lists 1980)
                     Genus Treponema Schaudinn 1905 (Approved Lists 1980)
                       Treponema pertenue (Castellani 1905) Castellani and Chalmers 1910 (Approved Lists 1980)