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 Fervidicoccales Perevalova et al. 2010 [monotypic]
           Family Fervidicoccaceae Perevalova et al. 2010 [monotypic]
             1 Genus Fervidicoccus Perevalova et al. 2010