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 Bacilli Ludwig et al. 2010
                   Order Bacillalesᵀ Prévot 1953 (Approved Lists 1980)
                     Family Bacillaceaeᵀ Fischer 1895 (Approved Lists 1980)
                       Genus Geobacillus Nazina et al. 2001
                         Geobacillus thermodenitrificans (Manachini et al. 2000) Nazina et al. 2001
                           1 Geobacillus thermodenitrificans subsp. thermodenitrificansᵀ (Manachini et al. 2000) Cihan et al. 2011
                           2 Geobacillus thermodenitrificans subsp. calidus Cihan et al. 2011