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 Clostridiales Prévot 1953 (Approved Lists 1980)
         Family Clostridiaceae Pribram 1933 (Approved Lists 1980)
           Genus Acetivibrio Patel et al. 1980
           Genus Acidaminobacter Stams and Hansen 1985
           Genus Anaerobacter Duda et al. 1996
           Genus Caloramator Collins et al. 1994
           Genus Natronincola corrig. Zhilina et al. 1999
           Genus Oxobacter Collins et al. 1994
           Genus Sarcina Goodsir 1842 (Approved Lists 1980)
           Genus Sporobacter Grech-Mora et al. 1996
           Genus Thermobrachium Engle et al. 1996
           Genus Tindallia Kevbrin et al. 1999
           1 Genus Clostridium Prazmowski 1880 (Approved Lists 1980)