[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)
           Family "Heliobacteriaceae" nom. inval. see Family Heliobacteriaceae Madigan and Asao 2010
             1 Genus Heliobacterium Gest and Favinger 1985
             2 Genus Cryptanaerobacter Juteau et al. 2005
             3 Genus Thermincola Sokolova et al. 2005
             4 Genus Heliobacillus Beer-Romero and Gest 1998
             5 Genus Heliophilum Ormerod et al. 1996
             6 Genus Heliorestis Bryantseva et al. 2000