[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 Clostridiales Prévot 1953 (Approved Lists 1980)
           1 Family Clostridiaceae Pribram 1933 (Approved Lists 1980)
           2 Family "Lachnospiraceae" nom. inval. see Family Lachnospiraceae Rainey 2010
           3 Family "Peptostreptococcaceae" see Family Peptostreptococcaceae Ezaki 2010
           4 Family "Eubacteriaceae" nom. inval. see Family Eubacteriaceae Ludwig et al. 2010
           5 Family Peptococcaceae Rogosa 1971 (Approved Lists 1980)
           6 Family "Heliobacteriaceae" nom. inval. see Family Heliobacteriaceae Madigan and Asao 2010
           7 Family "Acidaminococcaceae" Marchandin et al., 2010 see Family Acidaminococcaceae Marchandin et al. 2010
           8 Family Syntrophomonadaceae Zhao et al. 1993