[organisms] see Clade Biota Wagner 2004 [Wiemann, de Queiroz, Rowe, Planavsky, Anderson, Gogarten, Turner & Gauthier 2020]
   Domain Bacteria Woese et al. 1990
     Phylum "Proteobacteria" Garrity et al. 2005 see Superphylum Proteobacteria Craig et al. 2010
       Class Alphaproteobacteria Garrity et al. 2006
         Order Rhizobiales Kuykendall 2006
           Family Methylocystaceae Bowman 2006
             Genus Methylocystis (ex Whittenbury et al. 1970) Bowman et al. 1993
               1 Methylocystis parvus (ex Whittenbury et al. 1970) Bowman et al. 1993
               2 Methylocystis echinoides (ex Gal'chenko et al. 1977) Bowman et al. 1993
               3 Methylocystis rosea Wartiainen et al. 2006