procaryotes
   Domain Archaea Woese et al. 1990 stat. inval. see Domain Archaea Woese et al. 2024
     Phylum Crenarchaeota Garrity and Holt 2001 [monotypic]
       1 Class Thermoprotei Reysenbach 2001 nom. inval. see Class Thermoprotei Reysenbach 2002