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 Desulfurococcales Huber and Stetter 2001 nom. inval. see Order Desulfurococcales Huber and Stetter 2002
           Family Pyrodictiaceae Burggraf et al. 1997
             1 Genus Pyrodictiumᵀ Stetter et al. 1984
             2 Genus Hyperthermus Zillig et al. 1991
             3 Genus Pyrolobus Blöchl et al. 1999