Natura - nature actualia - actual entities Mundus Plinius - physical world naturalia - natural bodies [crown] 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 Genus Exilispira Imachi et al. 2008, incertae sedis [monotypic] 1 Exilispira thermophilaᵀ Imachi et al. 2008