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 Rickettsiales Gieszczykiewicz 1939 (Approved Lists 1980)
           Family "Holosporaceae" nom. inval. see Family Holosporaceae Görtz and Schmidt 2006
             Genus Polynucleobacter Heckmann and Schmidt 1987