Procaryotic Genera
   Domain "Archaea" Woese et al. 1990
     Phylum Euryarchaeota Garrity and Holt 2001
       Class Thermoplasmata Reysenbach 2001 [monotypic] see Class Thermoplasmata Reysenbach 2002
         Order Thermoplasmatalesᵀ Reysenbach 2001 see Order Thermoplasmatales Reysenbach 2002
           Family Picrophilaceae Schleper et al. 1996 [monotypic]
             Genus Picrophilusᵀ Schleper et al. 1996