rhodocyclales rhodocyclales the rhodocyclales are an order of the class betaproteobacteria in the phylum "pseudomonadota". following a major reclassification of the class in 2017, the previously monofamilial order was split into three families: rhodocyclaceae (type family) contains the genera rhodocyclus (type genus), azospira and propionivibrio. cells are curved rods, rings or spirillae. dominant respiratory quinones are menaquinone-8, ubiquinone-8 and rhodoquinone-8. g+c fractions are 61.6 - 65.3 mol%. azonexaceae contains the genera azonexus (type genus), dechloromonas, ferribacterium and quatrionicoccus. cells are curved rods or cocci. dominant respiratory quinone is ubiquinone-8. g+c fractions are 63.5 - 67.0 mol%. zoogloeaceae contains the genera zoogloea (type genus), thauera, uliginosibacterium and azoarcus. cells are rod shaped. dominant respiratory quinones are ubiquinone-8 and rhodoquinone-8. g+c fractions are 59.3 - 69.0 mol%. rhodocyclales two strains of zoogloea resiniphila. wild type is on the left. the right is a strain unable to form floc. scientific classification domain: bacteria phylum: pseudomonadota class: betaproteobacteria order: rhodocyclalesboden et al. 2017 (garrity, et al 2006) families rhodocyclaceae azonexaceae zoogloeaceae the genus azovibrio also falls within the order but is incertae sedis, falling between the zoogloeaeceae and the azonexaceae.