C. Mourerchauvire et al., THE OLDEST REPRESENTATIVE OF THE GENUS ST RUTHIO (AVES, STRUTHIONIDAE), STRUTHIO-COPPENSI N-SP, FROM THE LOWER MIOCENE OF NAMIBIA, Comptes rendus de l'Academie des sciences. Serie II. Sciences de la terre et des planetes, 322(4), 1996, pp. 325-332
Fossil hind limb bones of a didactyl ratite found at Elisabethfeld, a
Lower Miocene site in Namibia, represent the oldest known skeletal ele
ments of the genus Struthio. The same site has yielded egg-shells of '
'aepyornithoid'' pattern. This discovery indicates that didactyl ostri
ches probably originated in Africa in pre-Miocene times. They subseque
ntly spread to Eurasia during the Middle Miocene and later periods.