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 Halanaerobiales corrig. Rainey and Zhilina 1995
                     Family Halanaerobiaceaeᵀ corrig. Oren et al. 1984
                       Genus Halanaerobiumᵀ corrig. Zeikus et al. 1984
                         Halanaerobium fermentans corrig. Kobayashi et al. 2000