Natura - nature
   actualia - actual entities
     Mundus Plinius - physical world
       naturalia - natural bodies
         [crown] Clade Biota Wagner 2004 [Wiemann, de Queiroz, Rowe, Planavsky, Anderson, Gogarten, Turner & Gauthier 2020]
           Clade neomura Cavalier-Smith, 1987
             Domain Archaea Woese et al. 1990 [paraphyletic]
               Phylum Euryarchaeota Garrity and Holt 2001
                 Class Methanobacteria Boone 2002 [monotypic]
                   Order Methanobacterialesᵀ Balch and Wolfe 1981
                     Family Methanobacteriaceaeᵀ Barker 1956 (Approved Lists 1980)
                       1 Genus Methanobacteriumᵀ Kluyver and van Niel 1936 (Approved Lists 1980)
                       2 Genus Methanobrevibacter Balch and Wolfe 1981
                       3 Genus Methanosphaera Miller and Wolin 1985
                       4 Genus Methanothermobacter Wasserfallen et al. 2000