prokaryotes - bacteria see Domain Bacteria Woese et al. 1990
   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
             1 Genus Albibacter Doronina et al. 2001
             2 Genus Hansschlegelia Ivanova et al. 2010
             3 Genus Methylocystis (ex Whittenbury et al. 1970) Bowman et al. 1993
             4 Genus Methylopila Doronina et al. 1998
             5 Genus Methylosinus (ex Whittenbury et al. 1970) Bowman et al. 1993
             6 Genus Pleomorphomonas Xie and Yokota 2005
             7 Genus Terasakiella Satomi et al. 2002