Procaryotic Genera 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 "Nitrosomonadales" see Order Nitrosomonadales Garrity et al. 2006 Family Spirillaceae Migula 1894 (Approved Lists 1980) [monotypic] 1 Genus Spirillum Ehrenberg 1832 (Approved Lists 1980)