prokaryotes - bacteria see Domain Bacteria Woese et al. 1990
   Domain "Bacteria" Woese et al. 1990
     Phylum "Nitrospira" Garrity & Holt, 2001 [monotypic] see Phylum Nitrospirae Garrity and Holt 2001
       1 Class "Nitrospira" 2001 [monotypic]