Procaryotic Genera
   Domain "Bacteria" Woese et al. 1990
     Phylum Nitrospira Garrity & Holt, 2001 [monotypic] see Phylum Nitrospirae Garrity and Holt 2001
       Class "Nitrospira" 2001 [monotypic]
         1 Order "Nitrospirales" 2001 [monotypic]