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 "Candidatus Poseidoniota" corrig. Rinke et al. 2023 [monotypic]
                   Class "Candidatus Poseidoniia"ᵀ Rinke et al. 2021 [monotypic]
                     Order "Candidatus Poseidoniales"ᵀ Rinke et al. 2021
                       Family "Candidatus Thalassarchaeaceae" Rinke et al. 2021 [monotypic]
                         1 Genus "Candidatus Thalassarchaeum"ᵀ Rinke et al. 2021