[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 Thermoanaerobacter Wiegel and Ljungdahl 1982
               [Thermoanaerobacter brockii] (Zeikus et al. 1983) Lee et al. 1993
                 Thermoanaerobacter brockii subsp. finnii (Schmid et al. 1986) Cayol et al. 1995