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 Methanococci Boone 2002 [monotypic]
                   Order Methanococcalesᵀ Balch and Wolfe 1981
                     Family Methanococcaceaeᵀ Balch and Wolfe 1981
                       Genus Methanococcusᵀ Kluyver and van Niel 1936 (Approved Lists 1980)
                         1 Methanococcus aeolicus Kendall et al. 2006
                         2 Methanococcus maripaludis Jones et al. 1984
                         3 Methanococcus vannielii Stadtman and Barker 1951 (Approved Lists 1980)
                         4 Methanococcus voltae Balch and Wolfe 1981