Procaryotic Genera Domain "Bacteria" Woese et al. 1990 Phylum Proteobacteria Garrity and Holt 2001 see Phylum Proteobacteria Garrity et al. 2005 Class "Gammaproteobacteria" nom. inval. see Class Gammaproteobacteria Garrity et al. 2005 Order "Methylococcales" nom. inval. [monotypic] see Order Methylococcales Bowman 2005 Family Methylococcaceae Whittenbury and Krieg 1984 Genus Methylocaldum Bodrossy et al. 1998