Procaryotic Genera Domain "Archaea" Woese et al. 1990 Phylum Euryarchaeota Garrity and Holt 2001 Class Methanobacteria Boone 2001 nom. inval. [monotypic] see Class Methanobacteria Boone 2002 Order Methanobacterialesᵀ Balch and Wolfe 1981 Family Methanothermaceae Stetter 1982 [monotypic] 1 Genus Methanothermusᵀ Stetter 1982