Procaryotic Genera Domain "Bacteria" Woese et al. 1990 Phylum Proteobacteria Garrity and Holt 2001 see Phylum Proteobacteria Garrity et al. 2005 Class "Alphaproteobacteria" Garrity and Holt 2001 nom. nud. see Class Alphaproteobacteria Garrity et al. 2006 Order "Rhizobiales" see Order Rhizobiales Kuykendall 2006 Family "Rhodobiaceae" [monotypic] see Family Rhodobiaceae Garrity et al. 2006 1 Genus Rhodobium Hiraishi et al. 1995