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
                     Genus Thermoanaerobacterium Lee et al. 1993, incertae sedis
                       1 Thermoanaerobacterium aciditolerans Kublanov et al. 2007
                       2 Thermoanaerobacterium aotearoense Liu et al. 1996
                       3 Thermoanaerobacterium saccharolyticum Lee et al. 1993
                       4 Thermoanaerobacterium thermosaccharolyticum (McClung 1935) Collins et al. 1994
                       5 Thermoanaerobacterium thermosulfurigenes (Schink and Zeikus 1983) Lee et al. 1993
                       6 Thermoanaerobacterium xylanolyticum Lee et al. 1993