procaryotes
   Domain Archaea Woese et al. 1990
     Phylum Crenarchaeota Garrity and Holt 2001
       Class Thermoprotei Reysenbach 2001 see Class Thermoprotei Reysenbach 2002
         Order Sulfolobales Stetter 1989
           Family Sulfolobaceae Stetter 1989
             Genus Sulfurococcus Golovacheva et al. 1995