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 Thermoproteati Guy and Ettema 2024
                 Phylum Thermoproteotaᵀ Garrity and Holt 2021
                   Class "Candidatus Methanomethylicia" corrig. Vanwonterghem et al. 2020
                     Order "Candidatus Methanohydrogenicales" corrig. Berghuis et al. 2019 nom. pro-inval. [monotypic]
                       Family "Candidatus Methanohydrogenicaceae"ᵀ Berghuis et al. 2019 nom. pro-inval. [monotypic]
                         1 Genus "Candidatus Methanohydrogenicus"ᵀ Berghuis et al. 2021