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 Terrabacteria Battistuzzi et al. 2004
               Phylum Firmicutes corrig. Gibbons and Murray 1978 (Approved Lists 1980)
                 Class Clostridia Rainey 2010
                   Order Thermoanaerobacterales Wiegel 2010
                     Family Thermoanaerobacteraceaeᵀ Wiegel 2010
                       Genus Caldanaerobacter Fardeau et al. 2004
                         Caldanaerobacter subterraneusᵀ (Fardeau et al. 2000) Fardeau et al. 2004
                           Caldanaerobacter subterraneus subsp. tengcongensis (Xue et al. 2001) Fardeau et al. 2004