[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
             01 Genus Thermoanaerobacterium Lee et al. 1993
             01.0 Genus Acetogenium Leigh and Wolfe 1983 see Genus Thermoanaerobacterium Lee et al. 1993
             02 Genus Ammonifex Huber and Stetter 1996
             03 Genus Caldanaerobacter Fardeau et al. 2004
             03.0 Genus Carboxydibrachium corrig. Sokolova et al. 2001
             04 Genus Coprothermobacter Rainey and Stackebrandt 1993
             05 Genus Gelria Plugge et al. 2002
             06 Genus Mahella Bonilla Salinas et al. 2004
             07 Genus Moorella Collins et al. 1994 nom. illeg.
             08 Genus Sporotomaculum Brauman et al. 1998
             09 Genus Tepidanaerobacter Sekiguchi et al. 2006
             10 Genus Thermacetogenium Hattori et al. 2000
             11 Genus Thermanaeromonas Mori et al. 2002
             12 Genus Thermoanaerobacter Wiegel and Ljungdahl 1982
             12.0.1 Genus Thermoanaerobium Zeikus et al. 1983 see Genus Thermoanaerobacter Wiegel and Ljungdahl 1982
             12.0.2 Genus Thermobacteroides Ben-Bassat and Zeikus 1983 see Genus Thermoanaerobacter Wiegel and Ljungdahl 1982
             13 Genus Thermosediminibacter Lee et al. 2006
             14 Genus Thermovenabulum Zavarzina et al. 2002