prokaryotes - bacteria see Domain Bacteria Woese et al. 1990
   Domain "Bacteria" Woese et al. 1990
     Phylum "Firmicutes" corrig. Gibbons and Murray 1978 (Approved Lists 1980)
       Class Clostridia Rainey 2010
         Order Natranaerobiales Mesbah et al. 2007 [monotypic]
           Family Natranaerobiaceae Mesbah et al. 2007
             Genus Natranaerobius Mesbah et al. 2007