The Enigmatic Avian Oogenus Psammornis: A Review of Stratigraphic Evidence

Abstract

Psammornis rothschildi is an avian taxon established by Andrews in 1911 on the basis of eggshell fragments surface-collected near the city of Touggourt, in the north-eastern part of the Al-gerian Sahara. Since the initial discovery, a number of Psammornis specimens have been reported from various localities in North Africa (Algeria, Tunisia, Libya, Mauritania) and the Middle East (Saudi Arabia, Iran). Most of the finds lack a stratigraphic context, which has resulted in considerable confusion about the geological age of Psammornis, with attributions ranging from the Eocene to the Holocene. A review of the available evidence shows that only two groups of localities provide reasonably reliable stratigraphic evidence: the Segui Formation of SW Tunisia, apparently of latest Miocene age, and the Aguerguerian (Middle Pleistocene) of NW Mauritania. This suggests a fairly long time range for Psammornis. Psammornis eggs are, in all likelihood, those of giant ostriches, alt-hough the lack of associated skeletal material makes it difficult to interpret the eggshell fragments in evolutionary terms. However, the oological record suggests that giant ostriches have been present in Africa since the late Miocene, which leads to the reconsideration of some hypotheses about the palaeobiogeographical history of the Struthionidae. The lack of Psammornis eggs transformed by humans suggests that this giant ostrich did not survive until Epipalaeolthic or Neolithic times.