prokaryotes - bacteria see Domain Bacteria Woese et al. 1990 Domain "Archaea" Woese et al. 1990 Phylum "Euryarchaeota" Garrity and Holt 2001 Class "Methanomicrobia" Order Methanosarcinales Boone et al. 2002 Family Methermicoccaceae Cheng et al. 2007 [monotypic] 1 Genus Methermicoccus Cheng et al. 2007