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 Thermoproteales Zillig and Stetter 1982 Family Thermoproteaceae Zillig and Stetter 1982 1 Genus Caldivirga Itoh et al. 1999 2 Genus Pyrobaculum Huber et al. 1988 3 Genus Thermocladium Itoh et al. 1998 4 Genus Thermoproteus Zillig and Stetter 1982 5 Genus Vulcanisaeta Itoh et al. 2002