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 Rhodospirillales Pfennig and Trüper 1971 (Approved Lists 1980)
         Family Rhodospirillaceae Pfennig and Trüper 1971 (Approved Lists 1980)
           Genus Azospirillum Tarrand et al. 1979 (Approved Lists 1980)
           Genus Magnetospirillum Schleifer et al. 1992
           Genus Phaeospirillum Imhoff et al. 1998
           Genus Rhodocista Kawasaki et al. 1994
           Genus Rhodospira Pfennig et al. 1998
           Genus Rhodothalassium Imhoff et al. 1998
           Genus Rhodovibrio Imhoff et al. 1998
           Genus Roseospira Imhoff et al. 1998
           Genus Skermanella Sly and Stackebrandt 1999
           1 Genus Rhodospirillum Molisch 1907 (Approved Lists 1980)