Natura - nature
   actualia - actual entities
     Mundus Plinius - physical world
       naturalia - natural bodies
         [crown] Clade Biota Wagner 2004 [Wiemann, de Queiroz, Rowe, Planavsky, Anderson, Gogarten, Turner & Gauthier 2020]
           Clade neomura Cavalier-Smith, 1987
             Domain Archaea Woese et al. 1990 [paraphyletic]
               Phylum Euryarchaeota Garrity and Holt 2001
                 Class Thermoplasmata Reysenbach 2002 [monotypic]
                   Order Thermoplasmatalesᵀ Reysenbach 2002
                     Family Picrophilaceae Schleper et al. 1996 [monotypic]
                       Genus Picrophilusᵀ Schleper et al. 1996
                         1 Picrophilus oshimae Schleper et al. 1996
                         2 Picrophilus torridus Zillig et al. 1996