After Olson, 1975, and Sibley & Monroe, 1990
<==o Upupidae (hoopoes; harjalinnut) `--o Upupa (hoopoes; harjalinnut) |-- †U. antaios Olson, 1975 (santhelenanharjalintu) [St. Helena Isl.] |-- U. epops (hoopoe; harjalintu) `-- U. africana (African Hoopoe)
Reference(s):
- Feduccia, A., 1980: The Age of Birds.
–Harvard University Press, Cambridge, Massachusetts & London, England, 1980, IX-196 - Feduccia, A., 1997: The Origin and Evolution of Birds.
–Yale University Press, New Haven, 1996, x-420 - Olson, S. L., 1975: Paleornithology of St. Helena Island, South Atlantic Ocean.
–Smithsonian Contributions to Baleobiology: Vol. 23, pp. iv-49 - 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, - Sibley, C. G. & Monroe, B, L., 1990: Distribution and taxonomy of birds of the world.
–Yale University Press, New Haven & London, 1990. xxiv-1111