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. 2024
             Kingdom Pseudomonadati (Gibbons and Murray 1978) Oren and Göker 2024
               Phylum Spirochaetota Garrity and Holt 2021
                 Class Spirochaetiaᵀ Paster 2020
                   1 Genus Exilispira Imachi et al. 2008, incertae sedis [monotypic]
                   2 Order Brachyspirales Gupta et al. 2014 [monotypic]
                   3 Order Brevinematales Gupta et al. 2014
                   4 Order Leptospirales Gupta et al. 2014 [monotypic]
                   5 Order Spirochaetalesᵀ Buchanan 1917 (Approved Lists 1980)