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]
               Superphylum TACK Guy and Ettema 2011
                 Phylum Crenarchaeota Garrity and Holt 2001
                   Class Thermoprotei Reysenbach 2002
                     Order Thermoprotealesᵀ Zillig and Stetter 1982
                       Family Thermoproteaceaeᵀ Zillig and Stetter 1982
                         Genus Pyrobaculum Huber et al. 1988
                           1 Pyrobaculum aerophilum Völkl et al. 1996
                           2 Pyrobaculum arsenaticum Huber et al. 2001
                           3 Pyrobaculum calidifontis Amo et al. 2008
                           4 Pyrobaculum islandicumᵀ Huber et al. 1988
                           5 Pyrobaculum oguniense Sako et al. 2001
                           6 Pyrobaculum organotrophum Huber et al. 1988