Natura - nature actualia - actual entities Mundus Plinius - physical world naturalia - natural bodies [crown] Clade Biota Wagner 2004 [Wiemann, de Queiroz, Rowe, Planavsky, Anderson, Gogarten, Turner & Gauthier 2020] Clade neomura Cavalier-Smith, 1987 Domain Archaea Woese et al. 1990 [paraphyletic] Phylum Euryarchaeota Garrity and Holt 2001 Class "Methanomicrobia" Order Methanomicrobialesᵀ Balch and Wolfe 1981 Family Methanomicrobiaceaeᵀ Balch and Wolfe 1981 Genus Methanogenium Romesser et al. 1981 Methanogenium organophilum Widdel et al. 1989