A new Priabonian Chondrichthyans assemblage from the Western desert, Egypt: Correlation with the Fayum oasis

While the Middle/Late Eocene marine vertebrates in Egypt have been largely reported around the Fayum oasis, few reports were made elsewhere. Here we report a new fossil site (Km55) located near the Bahariya Oasis in the Western desert of Egypt. This fossiliferous outcrop has yielded abundant fossil material of invertebrates dated to the Middle/Late Eocene and some chondrichthyan remains that testify of a Priabonian age (MK11). More than twenty Selachian taxa were recovered in one level, including “Cretolamna “ twiggsensis, Misrichthys stromeri, Odontorhytis pappenheimi, ?Jacquhermania attiai, and the fauna is quite similar to some recovered from the Fayum area. However, this new association is clearly distinctive of an open marine environment during the extreme Late Eocene while the contemporaneous fossil sites farther east are deposited in shallower (e.g. Wadi Hitan) or continental environments (e.g. BQ-2). This suggests an E–W diachronous change in relative sea level on the Egyptian coastal shelf during the Late Eocene period, with a general deepening along strike to the West.

► Eocene Fayum area was recently registered in the UNESCO World Heritage for their fossils.
► Datation of these deposits is essential to understand the evolutionary process.
► Discovery of a new locality with similar fauna increase our time accuracy.
► Increase our knowledge of the dynamic of paleogeography.
► Opens future opportunities to improve our fossil record.