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 Peptostreptococcaceae Ezaki 2010
             1 Genus Anaerosphaera Ueki et al. 2009
             2 Genus Filifactor Collins et al. 1994
             3 Genus Peptostreptococcus Kluyver and van Niel 1936 (Approved Lists 1980)
             4 Genus Sporacetigenium Chen et al. 2006
             5 Genus Tepidibacter Slobodkin et al. 2003