procaryotes
   Domain Archaea Woese et al. 1990 stat. inval. see Domain Archaea Woese et al. 2024
     Phylum Euryarchaeota Garrity and Holt 2001
       Class Methanococci Boone 2001 nom. inval. see Class Methanococci Boone 2002
         1 Order Methanococcalesᵀ Balch and Wolfe 1981
         2 Order Methanomicrobiales Balch and Wolfe 1981
         3 Order Methanosarcinales Boone et al. 2001 nom. inval. see Order Methanosarcinales Boone et al. 2002