Taxonomy and morphological study on the vertebrate remains of Shark and rays fauna from the Middle and Late Eocene succession, Fayoum Depression, Egypt

Abstract

Well preserved vertebrate remains of Shark and ray fauna from the Middle and Late Eocene succession ofFayoum depression, at Gebal Qasr El-Sagha area have been documented and studied in details. Four stratigraphic sectionsare measured, described and sampled in the field at Hussein Wally Village, Birket Qarun, Qasr el-Sagha and Wadi el-Afreet. Lithostratigraphically, the studied succession is divided into three formations arranged from base to top intoGehannam, Birket Qarun and Qasr el-Sagha formations. This Eocene sequence provides by far the most complete view ofthe endemic African vertebrate fauna. Identification of the basic pattern of fish remains and taxonomic evaluation revealedthat the recorded shark and rays taxa belong to 3 classes, 7 orders, 12 families, 18 genera, and 21 species. The identifiedtaxa are macro-scale, collected on the surface, and known either from teeth or rostral remains. A taxonomic account anddetailed morphologic description of the fossils shark, rays and bony fish teeth have been achieved. The depositionalenvironments in the studied Middle-Late Eocene age sequence are interpreted. The abundance of recognized vertebratefauna indicates environments varying from open marine shelf with low energy conditions to restricted marine shallowwater conditions. However, the frequent distribution of macrofauna with intense bioturbation in sandstones of Birket QarunFormation is a good indicator of restricted shallow water conditions.