[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 Gammaproteobacteria Garrity et al. 2005
         Order Methylococcales Bowman 2005
           Family Methylococcaceae Whittenbury and Krieg 1984
             1 Genus Methylococcus Foster and Davis 1966 (Approved Lists 1980)
             2 Genus Methylobacter Bowman et al. 1993
             3 Genus Methylocaldum Bodrossy et al. 1998
             4 Genus Methylohalobius Heyer et al. 2005
             5 Genus Methylomicrobium Bowman et al. 1995
             6 Genus Methylomonas (ex Leadbetter 1974) Whittenbury and Krieg 1984
             7 Genus Methylosarcina Wise et al. 2001
             8 Genus Methylosphaera Bowman et al. 1998