prokaryotes - bacteria see Domain Bacteria Woese et al. 1990 Domain "Archaea" Woese et al. 1990 Phylum "Crenarchaeota" Garrity and Holt 2001 [monotypic] Class Thermoprotei Reysenbach 2002 Order Desulfurococcales Huber and Stetter 2002 Family Pyrodictiaceae Burggraf et al. 1997 Genus Hyperthermus Zillig et al. 1991