[organisms] see Clade Biota Wagner 2004 [Wiemann, de Queiroz, Rowe, Planavsky, Anderson, Gogarten, Turner & Gauthier 2020]
   Domain Bacteria Woese et al. 1990 stat. inval. see Domain Bacteria Woese et al. 2024
     Phylum "Proteobacteria" Garrity et al. 2005 stat. inval. see Phylum Pseudomonadota Garrity et al. 2021
       Class Alphaproteobacteria Garrity et al. 2006
         Order Rhizobiales Kuykendall 2006 see Order Hyphomicrobiales Douglas 1957 (Approved Lists 1980)
           Family Methylocystaceae Bowman 2006
             1 Genus Methylocystis (ex Whittenbury et al. 1970) Bowman et al. 1993
             2 Genus Albibacter Doronina et al. 2001
             3 Genus Methylopila Doronina et al. 1998
             4 Genus Methylosinus (ex Whittenbury et al. 1970) Bowman et al. 1993
             5 Genus Pleomorphomonas Xie and Yokota 2005
             6 Genus Terasakiella Satomi et al. 2002