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 "Methanomicrobia" Garrity et al. 2005 nom. inval.
                     Order Methanomicrobialesᵀ Balch and Wolfe 1981
                       1 Family Methanocalculaceae Zhilina et al. 2014 [monotypic]
                       2 Family Methanocorpusculaceae Zellner et al. 1989
                       3 Family Methanomicrobiaceaeᵀ Balch and Wolfe 1981
                       4 Family Methanoregulaceae Sakai et al. 2012
                       5 Family Methanospirillaceae Boone et al. 2002