Campanian-early Eocene marine bivalves from the Kharga Oasis, Western Desert, Egypt; systematic palaeontology and palaeobiogeography

Thirty-six species of bivalves, belonging to 22 genera, representative of 16 orders, are systematically described from five upper Campanian-lower Eocene sections in the Kharga Oasis. Stratigraphically, 15 species were recorded from the Palaeocene, 8 from the lower Eocene, 8 from the Maastrichtian, 3 from the Campanian, 1 from the Campanian-Maastrichtian and 1 from the Maastrichtian-Palaeocene. The paleobiogeographic distribution of the Campanian-Maastrichtian bivalves reveals high degree of marine connection between the South Tethyan province and the West Africa, Middle East, southern Europe, South America and India provinces. Consequently, the Campanian-Maastrichtian bivalves have a strong southern Tethyan affinity. The early Palaeogene bivalves are markedly endemic to the Egyptian territory, which can argued to the isolation in marine environment by the localised tectonic events and/or the pronounced climatic changes. Accordingly, the palaeobiogeographic distribution of the studied bivalves was wider in the Late Cretaceous (Campanian-Maastrichtian) than in the early Palaeogene (Palaeocene-early Eocene).

Automated summary

The study of bivalves in the Kharga Oasis of Egypt revealed different paleobiogeographic distributions, with Late Cretaceous to Maastrichtian bivalves showing a strong marine connection with the South Tethyan province and other regions, while early Eocene bivalves were more limited to the Egyptian territory.