procaryotes
   Domain Bacteria Woese et al. 1990
     Phylum Nitrospirae Garrity and Holt 2001
       Class "Nitrospira" 2001
         Order "Nitrospirales" 2001
           Family "Nitrospiraceae" 2001
             1 Genus Nitrospira Watson et al. 1986
             2 Genus Leptospirillum (ex Markosyan 1972) Hippe 2000
             3 Genus "Magnetobacterium" Murray and Stackebrandt 1995
             4 Genus Thermodesulfovibrio Henry et al. 1994