procaryotes
   Domain Archaea Woese et al. 1990
     Phylum Euryarchaeota Garrity and Holt 2001
       Class Methanococci Boone 2001 nom. inval. see Class Methanococci Boone 2002
         Order Methanosarcinales Boone et al. 2001 nom. inval. see Order Methanosarcinales Boone et al. 2002
           Family Methanosaetaceae Boone et al. 2001 nom. inval. see Family Methanosaetaceae Boone et al. 2002 nom. illeg.
             1 Genus Methanosaeta Patel and Sprott 1990 nom. illeg. see Genus Methanothrix Huser et al. 1983