prokaryotes - bacteria see Domain Bacteria Woese et al. 1990 stat. inval.
   Domain "Archaea" Woese et al. 1990 stat. inval. see Domain Archaea Woese et al. 2024
     Phylum "Crenarchaeota" Garrity and Holt 2002 stat. inval. [monotypic] see Phylum Thermoproteota Garrity and Holt 2021
       Class Thermoprotei Reysenbach 2002
         Order Sulfolobales Stetter 1989 [monotypic]
           Family Sulfolobaceae Stetter 1989
             1 Genus Acidianus Segerer et al. 1986
             2 Genus Desulfurolobus Zillig and Böck 1987 see Genus Acidianus Segerer et al. 1986
             3 Genus Metallosphaera Huber et al. 1989
             4 Genus Stygiolobus Segerer et al. 1991
             5 Genus Sulfolobus Brock et al. 1972 (Approved Lists 1980)
             6 Genus Sulfurisphaera Kurosawa et al. 1998
             7 Genus Sulfurococcus Golovacheva et al. 1995