Cassidula schmackeriana MÖLLENDORFF, 1895: MỘT LOÀI ỐC MỚI CHO KHU HỆ ĐỘNG VẬT RỪNG NGẬP MẶN VIỆT NAM (GASTROPODA: ELLOBIIDAE)

Cassidula schmackeriana MÖLLENDORFF, 1895: A NEW SPECIES RECORDED TO THE FAUNA OF VIETNAMESE MANGROVES(GASTROPODA: ELLOBIIDAE)The genus Cassidula belongs to the family Ellobiidae and was established by Férussac (1821) based on the type species Cassidula aurisfelis (Bruguière, 1789). To date, 23 nominal Cassidula species have been recognized worldwide, with a distribution range in the Indian Ocean-West Pacific. C. schmackeriana was discovered in the mangrove forest of Quang Ninh (Tien Yen district), Hai Phong (Cat Ba National Park), Thanh Hoa (Lach Bang estuary, Nghi Son), Ba Ria-Vung Tau (Dat Do district), this finding is the first record of this species for the fauna of Vietnam. C. schmackeriana is characterized by its medium size, oval shell with a high spire that tapers at the top; the shell’s horny layer is thick, forming many soft hairs and small scales. It has a large, prominent, “S”-shaped parietal plica that extends from the parietal side to the basal side of the aperture. The aperture denticles are large, and include the first ivory-white, oblique lamella, which protruddes inwardly into the aperture; a second small and, sometimes indistinct lamella; a ridge-shaped, purple, “S”-shaped columellar lamella.