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?]
             Superphylum Planctomycetes-Verrucomicrobia-Chlamydiae (PVC) Wagner and Horn 2006
               Phylum Chlamydiae Garrity and Holt 2012 [monotypic]
                 Class Chlamydiaeᵀ Cavalier-Smith 2002 [monotypic]
                   Order Chlamydialesᵀ Storz and Page 1971 (Approved Lists 1980)
                     1 Family Chlamydiaceaeᵀ Rake 1957 (Approved Lists 1980)
                     2.1 Family Simkaniaceae Everett et al. 1999
                     2.2.1 Family Waddliaceae Rurangirwa et al. 1999 [monotypic]
                     2.2.2 Family Parachlamydiaceae Everett et al. 1999