Identification:
- Large snail, elongated shell with 9-10 whorls. Apex pointed, often eroded. Whorls flattened, constricted in the upper half. Shell surface is dark brown with numerous coarse spiral lines and several large longitudinal ridges on each whorl, slightly twisted to the left. Aperture oval, narrow, occupying 1/3 of the shell height. The lip is sharp, forming a large pointed lip below, slightly constricted above, creating a sharp angle. The columellar glaze is developed, opaque white.
Biology and Ecology:
- Lives on the bottom of rivers, streams, ponds in mountainous and plain areas adjacent to mountains, on soft bottoms such as mud, or mud-sand.
Distribution:
- Within Vietnam: Hòa Bình, Ninh Bình, Hải Phòng (Cát Bà Island).
- Worldwide: China (Hainan, Hong Kong).
Value:
- Of scientific value because shell specimens have been found at archaeological sites in Ninh Bình and Cát Bà.
Status:
- Before 2001, only dead shells were collected at archaeological sites in Cúc Phương and Cát Bà. A survey at Vân Long lagoon (Ninh Bình) in September 2001 found many live individuals of this species with a density of 5-15 individuals/m2. This species is being heavily exploited. However, there is not enough information on the status of this species.
Red List Category:
- DD (Data Deficient).
Conservation Measures:
- Included in the Vietnam Red Book. It is recommended to reduce exploitation intensity, and to research the biological, ecological characteristics, and population distribution of this species.