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?]
             Superphylum "Proteobacteria" Craig et al. 2010
               Phylum "Gammaproteobacteria" Garrity et al., 2005 [monotypic]
                 Class Gammaproteobacteriaᵀ Garrity et al. 2005
                   Order Chromatiales Imhoff 2005
                     Family Chromatiaceae Bavendamm 1924 (Approved Lists 1980)
                       Genus Thiococcus (ex Eimhjellen et al. 1967) Imhoff et al. 1998 [monotypic]
                         Thiococcus pfennigiiᵀ (Eimhjellen 1970) Imhoff et al. 1998