Kingdom Bacteria Cavalier-Smith 2002 stat. inval. [paraphyletic?] - bacteria see Domain Bacteria Woese et al. 1990 stat. inval.
   Subkingdom Unibacteria Cavalier-Smith 2002 [paraphyletic?] see Domain Bacteria Woese et al. 1990 stat. inval.
     Division Archaebacteria Cavalier-Smith 2002 see Domain Archaea Woese et al. 1990 stat. inval.
       Subdivision Crenarchaeota Cavalier-Smith 2002 [monotypic] see Phylum Crenarchaeota Garrity and Holt 2002 stat. inval.
         Class Crenarchaeota Cavalier-Smith 2002 nom. rej. see Class Thermoprotei Reysenbach 2002
           Order Sulfolobales Stetter 1989