prokaryotes - bacteria see Domain Bacteria Woese et al. 1990 stat. inval.
   Domain "Bacteria" Woese et al. 1990 stat. inval. see Domain Bacteria Woese et al. 2024
     Phylum "Firmicutes" (Gibbons and Murray 1978) Garrity and Holt 2001 stat. inval. see Phylum Bacillota Gibbons and Murray 2021
       Class Clostridia Rainey 2010
         Order Clostridiales Prévot 1953 (Approved Lists 1980) see Order Eubacteriales Buchanan 1917 (Approved Lists 1980)
           Family Heliobacteriaceae Madigan and Asao 2010
             1 Genus Heliobacillus Beer-Romero and Gest 1998 see Genus Heliobacterium Gest and Favinger 1985
             2 Genus Heliobacterium Gest and Favinger 1985
             3 Genus Heliophilum Ormerod et al. 1996
             4 Genus Heliorestis Bryantseva et al. 2000