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]
           Domain Bacteria Woese et al. 1990 [paraphyletic?]
             Phylum Aquificae Reysenbach 2001 [monotypic]
               Class Aquificaeᵀ Reysenbach 2002
                 Order Aquificalesᵀ Reysenbach 2002
                   Family Hydrogenothermaceae Eder and Huber 2003
                     1 Genus Hydrogenothermusᵀ Stöhr et al. 2001 [monotypic]
                     2 Genus Persephonella Götz et al. 2002
                     3 Genus Sulfurihydrogenibium Takai et al. 2003
                     4 Genus Venenivibrio Hetzer et al. 2008 [monotypic]