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
                         1 Methylocaldum gracile (ex Romanovskaya et al. 1978) Bodrossy et al. 1998
                         2 Methylocaldum marinum Takeuchi et al. 2014
                         3 Methylocaldum szegediense Bodrossy et al. 1998
                         4 Methylocaldum tepidum Bodrossy et al. 1998