Systematics, palaeoecology and taphonomy of Turonian oysters from the northern Gabon Coastal Basin

The systematic, paleoecology and taphonomy of the Turonian (Azile Formation) oysters fauna from the geological section PK 12, South of Libreville - Gabon, are carried out. Twelve species from seven genera are described. Genera Curvostrea Vyalov, 1936; Gryphaeostrea Conrad, 1865; Gyrostrea Mirkamalov, 1963; Ilymatogyra Stenzel, 1971; Ostrea Linnaeus, 1758; Rhynchostreon Bayle, 1878 and all species are recorded herein for the time in Gabonese coastal basin. The assemblage is dominated by representatives of the genus Ostrea and can be regarded as parautochthonous. The oyster shells are thin and thick with medium to large size. The paleoecological study indicates a nearshore shallow marine environment with high energy, nutrient-rich and well oxygenated water column. Taphonomic observations show that shells of oyster are affected by disarticulation. Bioerosion, traces of predators and encrustation are scarcity or absence. Abrasion, breackage and high fragmentation of shell are generally lacking.