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 Thiotrichales Garrity et al. 2005
                     Family Piscirickettsiaceae Fryer and Lannan 2005
                       Genus Thiomicrospira Kuenen and Veldkamp 1972 (Approved Lists 1980)
                         Thiomicrospira psychrophila Knittel et al. 2005