[organisms] see Clade Biota Wagner 2004 [Wiemann, de Queiroz, Rowe, Planavsky, Anderson, Gogarten, Turner & Gauthier 2020]
   Domain Bacteria Woese et al. 1990 stat. inval. see Domain Bacteria Woese et al. 2024
     Phylum "Proteobacteria" Garrity et al. 2005 stat. inval. see Phylum Pseudomonadota Garrity et al. 2021
       Class Betaproteobacteria Garrity et al. 2006
         Order Nitrosomonadales Garrity et al. 2006 nom. illeg. see Order Spirillales Prévot 1940 (Approved Lists 1980)
           Family Spirillaceae Migula 1894 (Approved Lists 1980)
             Genus Spirillum Ehrenberg 1832 (Approved Lists 1980)
               1 Spirillum volutans Ehrenberg 1832 (Approved Lists 1980)