[organisms] see Clade Biota Wagner 2004 [Wiemann, de Queiroz, Rowe, Planavsky, Anderson, Gogarten, Turner & Gauthier 2020]
   Domain Bacteria Woese et al. 1990
     Phylum Firmicutes corrig. Gibbons and Murray 1978 (Approved Lists 1980)
       Class "Clostridia" Garrity et al. 2001 nom. ined. see Class Clostridia Rainey 2010
         Order "Thermoanaerobacteriales" see Order Thermoanaerobacterales Wiegel, 2010
           Family "Thermoanaerobacteriaceae" see Family Thermoanaerobacteraceae Wiegel, 2010
             Genus Thermoanaerobacterium Lee et al. 1993
               1 Thermoanaerobacterium thermosulfurigenes (Schink and Zeikus 1983) Lee et al. 1993
               2 Thermoanaerobacterium aotearoense Liu et al. 1996
               3 Thermoanaerobacterium polysaccharolyticum Cann et al. 2001 see Caldanaerobius polysaccharolyticus (Cann et al. 2001) Lee et al. 2008
               4 Thermoanaerobacterium saccharolyticum Lee et al. 1993
               5 Thermoanaerobacterium thermosaccharolyticum (McClung 1935) Collins et al. 1994
               6 Thermoanaerobacterium xylanolyticum Lee et al. 1993
               7 Thermoanaerobacterium zeae Cann et al. 2001 see Caldanaerobius zeae (Cann et al. 2001) Lee et al. 2008