Class Proteobacteria Stackebrandt et al. 1988 nom. rej. see Phylum Proteobacteria Garrity and Holt 2001 nom. nud.
   Subclass alpha see Class Alphaproteobacteria "Garrity and Holt 2001" nom. nud.
     Group 4 see Order Sphingomonadales "Garrity and Holt 2001" nom. nud.
       Family Sphingomonadaceae Kosako et al. 2000
         Genus Sphingomonasᵀ Yabuuchi et al. 1990
           Sphingomonas ursincola (Yurkov et al. 1997) Yabuuchi et al. 1999 see Blastomonas ursincola (Yurkov et al. 1997) Hiraishi et al. 2000