Procaryotic Genera Domain "Archaea" Woese et al. 1990 Phylum Crenarchaeota Garrity and Holt 2001 [monotypic] Class Thermoprotei Reysenbach 2001 see Class Thermoprotei Reysenbach 2002 Order Thermoprotealesᵀ Zillig and Stetter 1982 Family Thermoproteaceae Zillig and Stetter 1982 1 Genus Thermoproteusᵀ Zillig and Stetter 1982 2 Genus Caldivirga Itoh et al. 1999 3 Genus Pyrobaculum Huber et al. 1988 4 Genus Thermocladium Itoh et al. 1998