Domain Bacteria Woese et al. 1990 Phylum Proteobacteria Garrity and Holt 2001 see Phylum Proteobacteria Garrity et al. 2005 Class "Betaproteobacteria" Garrity et al. 2001 nom. ined. see Class Betaproteobacteria Garrity et al. 2006 Order "Rhodocyclales" see Order Rhodocyclales Garrity et al. 2006 1 Family "Rhodocyclaceae" see Family Rhodocyclaceae Garrity et al. 2006