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
         Order Sulfolobales Stetter 1989 [monotypic]
           Family Sulfolobaceae Stetter 1989
             Genus Metallosphaera Huber et al. 1989