Natura - nature
   actualia - actual entities
     Mundus Plinius - physical world
       naturalia - natural bodies
         Clade Biota Wagner 2004 [Wiemann, de Queiroz, Rowe, Planavsky, Anderson, Gogarten, Turner & Gauthier 2020]
           Clade neomura Cavalier-Smith, 1987
             Domain Archaea Woese et al. 2024 [paraphyletic]
               Kingdom Methanobacteriati (Garrity and Holt 2023) Oren and Göker 2024
                 Phylum Methanobacteriotaᵀ Garrity and Holt 2023
                   Class Methanobacteriaᵀ Boone 2002 [monotypic]
                     Order Methanobacterialesᵀ Balch and Wolfe 1981
                       Family Methanobacteriaceaeᵀ Barker 1956 (Approved Lists 1980)
                         Genus Methanobacteriumᵀ Kluyver and van Niel 1936 (Approved Lists 1980)
                           Methanobacterium espanolae Patel et al. 1990