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 Methylococcales Bowman 2005
                     Family Methylococcaceaeᵀ Whittenbury and Krieg 1984
                       Genus Methylocaldum Bodrossy et al. 1998
                         Methylocaldum gracile (ex Romanovskaya et al. 1978) Bodrossy et al. 1998