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 "Rhodobacterales" [monotypic] see Order Rhodobacterales Garrity et al. 2006 Family "Rhodobacteraceae" see Family Rhodobacteraceae Garrity et al. 2006 Genus Ahrensia Uchino et al. 1999