[organisms] see Clade Biota Wagner 2004 [Wiemann, de Queiroz, Rowe, Planavsky, Anderson, Gogarten, Turner & Gauthier 2020]
   Domain Bacteria Woese et al. 1990
     Phylum "Proteobacteria" Garrity et al. 2005 see Superphylum Proteobacteria Craig et al. 2010
       Class Betaproteobacteria Garrity et al. 2006
         Order Nitrosomonadales Garrity et al. 2006
           Family Nitrosomonadaceae Garrity et al. 2006
             Genus Nitrosospira Winogradsky and Winogradsky 1933 (Approved Lists 1980)
               1 Nitrosospira briensis Winogradsky and Winogradsky 1933 (Approved Lists 1980)
               2 Nitrosospira multiformis (Watson et al. 1971) Head et al. 1995
               3 Nitrosospira tenuis (ex Harms et al. 1976) Head et al. 1995