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
         1 Order Acidilobales Prokofeva et al. 2009
         2 Order Cenarchaeales Cavalier-Smith 2002 [monotypic]
         3 Order Desulfurococcales Huber and Stetter 2002
         4 Order Fervidicoccales Perevalova et al. 2010 [monotypic]
         5 Order Sulfolobales Stetter 1989 [monotypic]
         6 Order Thermoproteales Zillig and Stetter 1982