Aptian–Albian Oysters from the Southwestern Spurs of the Gissar Ridge. Part 2. Genera Ceratostreon Bayle, Pseudogyra Mirkamalov, and Costagyra Vialov

Representatives of the genera Ceratostreon Bayle, 1878, Pseudogyra Mirkamalov, 1971 and Costagyra Vialov, 1936 (Gryphaeidae, Exogyrinae) from the Aptian and Albian of the southwestern spurs of the Gissar Ridge are revised. In the Aptian and Albian, the genus Ceratostreon is represented by the species C. trigonalis (Mirkamalov), the genus Pseudogyra is represented by the species Pseudogyra pennata Mirkamalov, and the genus Costagyra is represented by the species C. luppovi (Mirkamalov).