Taphonomy and Paleoecology of the Middle Miocene oysters from Wadi Sudr, Gulf of Suez, Egypt

The Upper Rudeis Formation (Middle Miocene, Langhian) of Wadi Sudr, Gulf of Suez, Egypt contains thick-bedded deposits of oysters. The oyster shells are large and massive. The paleoecological study of these oyster beds has revealed a nearshore shallow marine origin of the Upper Rudeis Formation with storm influence during the accumulation of their oyster shells. Taphonomic observations indicate that these shells are highly altered by disarticulation, bioerosion and encrustation. Abrasion, breakage and high fragmentation of shells are generally lacking. In addition, the studied oyster shells provide some traces of predation. Thicker shells and faster growth rates in oysters may reflect the greater exposure to fully marine predation and bioerosion, as well as to the conditions associated with higher salinity. Borings occur on the external and internal surfaces of their shells during the pre and/or post-mortem. They can be regarded as relatively diverse, being represented by the following ichnotaxa; Oichnus (O.) paraboloides Bromley 1981, O. simplex Bromley, 1981, Entobia isp., Rogerella isp. and Radulichnus isp