<==o †Eogruidae
   |-- †Sonogrus gregalis
   `--o †Eogrus
      |-- †E. aeola
      |-- †E. crudus
      |-- †E. turanicus
      `?- †E. wetmorei


Reference(s):

Feduccia, A., 1980: The Age of Birds.

–Harvard University Press, Cambridge, Massachusetts & London, England, 1980, IX-196
Feduccia, A., 1996: The Origin and Evolution of Birds.

–Yale University Press, New Haven, 1996, x-420

Olson, S. L., 1985: The fossil record of birds. 79-239.

in Farner, D., King, J. & Parkes, K. (eds.), 1985: Avian Biology. vol VIII.

–Academic Press, New York. 1985.