New phiocricetomyine rodents (Hystricognathi) from the Jebel Qatrani Formation, Fayum Depression, Egypt

Abstract

Background The rich rodent assemblages from the Eocene–Oligocene deposits of the Jebel Qatrani Formation (Fayum Depression, Egypt) have important implications for our understanding of the origin and paleobiogeography of Hystricognathi, a diverse clade that is now represented by the Afro-Asiatic Hystricidae, New World Caviomorpha, and African Phiomorpha. Methods Here we present previously undescribed material of the enigmatic hystricognath clade Phiocricetomyinae, from two stratigraphic levels in the lower sequence of the Jebel Qatrani Formation—a new genus and species (Qatranimys safroutus) from the latest Eocene Locality 41 (~34 Ma, the oldest and most productive quarry in the formation) and additional material of Talahphiomys lavocati from that species’ type locality, early Oligocene Quarry E (~31–33.2 Ma). Results The multiple specimens of Qatranimys safroutus from L-41 document almost the entire lower and upper dentition, as well as mandibular fragments and the first cranial remains known for a derived phiocricetomyine. Specimens from Quarry E allow us to expand comparisons with specimens from Libya (late Eocene of Dur at-Talah and early Oligocene of Zallah Oasis) that have been placed in T. lavocati, and we show that the Dur at-Talah and Zallah specimens do not pertain to this species. These observations leave the Fayum Quarry E as the only locality where T. lavocati occurs.