Procaryotic Genera
   Domain "Archaea" Woese et al. 1990
     Phylum Crenarchaeota Garrity and Holt 2001 [monotypic]
       Class Thermoprotei Reysenbach 2001 nom. inval. 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