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
                       Family Methanomicrobiaceaeᵀ Balch and Wolfe 1981
                         Genus Methanoculleus Maestrojuán et al. 1990
                           01 Methanoculleus bourgensis corrig. (Ollivier et al. 1986) Maestrojuán et al. 1990
                           02 Methanoculleus chikugoensis Dianou et al. 2001
                           03 Methanoculleus horonobensis Shimizu et al. 2013
                           04 Methanoculleus hydrogenitrophicus Tian et al. 2010
                           05 Methanoculleus marisnigri (Romesser et al. 1981) Maestrojuán et al. 1990
                           06 Methanoculleus olentangyi (Corder et al. 1988) Maestrojuán et al. 1990
                           07 Methanoculleus palmolei Zellner et al. 1998
                           08 Methanoculleus receptaculi Cheng et al. 2008
                           09 Methanoculleus submarinus Mikucki et al. 2003
                           10 Methanoculleus taiwanensis Weng et al. 2015
                           11 Methanoculleus thermophilus corrig. (Rivard and Smith 1982) Maestrojuán et al. 1990