Chinese mystery snail

Taxonomy of the introduced populations of Oriental mystery snails is confusing and there are many scientific names in use.[5] There has also been debate regarding whether or not Cipangopaludina chinensis malleata and Cipangopaludina japonica in North America are synonymous and simply different phenotypes of the same species.[5] For example USGS database considers the two as separate species.[5] Smith (2000)[6] argues that Cipangopaludina is a subgenus of Bellamya; however, because most North American literature does not use the genus Bellamya to refer to these introduced snails, Oriental mystery snails discussed here are referred to by the name Cipangopaludina.[5] Literature cited in the USGS database regarding the Chinese mystery snail may employ the following names: Cipangopaludina chinensis, Cipangopaludina chinensis malleatus, Cipangopaludina chinensis malleata, Viviparus malleatus, Viviparus chinensis malleatus, Bellamya chinensis and Bellamya chinensis malleatus.[5]

Shell of Bellamya chinensis

Species of the genus Cipangopaludina can be identified by their relatively large globose shells and concentrically marked opercula.[5] The shell is conical and thin but solid, with a sharp apex and relatively higher spire and distant body whorl.[7] This species has a small and round umbilicus and the spire is produced at an angle of 65–80°.[5] Cipangopaludina chinensis exhibits light coloration as a juvenile and olive green, greenish brown, brown or reddish brown pigmentation as an adult.[5] The inner coloration is white to pale blue.[5]

The surface of the shell is smooth with clear growth lines.[7] The shell has 6.0–7.0 whorls.[5]

Bellamya chinensis is a large gastropod species generally 40 millimetres (1.6 in) in shell height and 30 millimetres (1.2 in) in shell width, the largest being 60 millimetres (2.4 in) in height and 40 millimetres (1.6 in) wide.[7] The shell height can reach up to 65 millimetres (2.6 in).[5] Cipangopaludina chinensis has a width to height ratio of 0.74–0.82.[5]

The aperture is ovoid with a simple outer lip and inner lip.[7]

In juveniles, the last shell whorl displays a distinct carina, and the shell contains grooves with 20 striae/mm between each groove.[5] Juveniles also have a detailed pattern on their periostracum consisting of two apical and three body whorl rows of hairs with long hooks on the ends, distinct ridges and many other hairs with short hooks.[5]

The shell of Cipangopaludina chinensis grows allometrically (the height increasing faster than the width) and does so at a decreased rate in comparison with Cipangopaludina japonica, such that the adult shell is less elongate than that of its congener.[5] The radula also may differ between Cipangopaludina japonica and Cipangopaludina chinensis, but there is so much variation even within one species that it is not a good diagnostic characteristic.[5] However, as a general guide, in one North American population, the radula of Cipangopaludina chinensis had seven small cusps on the marginal tooth and a large central cusp with four small cusps on either side.[5]

Mystery snails (unlike apple snails) do not possess a siphon. They give live birth, and like all aquatic snails they only have one set of tentacles.

Though native to East Asia from the tropics of Indochina to northern China, this species has established itself in North America.

The native range is from Southeast Asia to Japan and eastern Russia.[5] This species is widely distributed in China including the Chinese Loess Plateau.[7]

This species prefers freshwater lakes with soft, muddy or silty bottoms,[5] reservoirs, slow-moving freshwater rivers, streams,[5] paddy fields, and ponds with aquatic grass, creeping at the bottom of the water or on aquatic grasses.[7] It prefers lentic water bodies with silt, sand, and mud substrate in eastern North America, although it can survive in slower regions of streams as well.[5] It can tolerate conditions in stagnant waters near septic tanks.[5]

This species has been found in waters in eastern North America with pH 6.5–8.4, calcium concentration of 5–97 ppm, magnesium concentration of 13–31 ppm, oxygen concentration of 7–11 ppm, depths of 0.2–7m, conductivity of 63–400 μmhos/cm, and sodium concentration of 2–49 ppm.[5]

The optimal water temperature for it to grow and develop is between 20 and 28 °C.[7] It will hibernate while water temperature is lower than 10-15 °C or higher than 30 °C.[7]

This species constitutes one of the three predominant freshwater snails found in Chinese markets.[18] This snail is extensively used as part of the human diet in most places in China because the meat of the snail is considered delicious, being rich in nutrition, with a high content of protein and low fat content.[7] Moreover, in China it is also used as a medicine for treatment of digestive disease.[7]

Its shells are abundant in archaeological sites in the Guanzhong Basin of Northwestern China from the Mid-Late Neolithic age.[7] These are remains of prehistoric meals. The flesh was eaten mainly as subsidiary food.[7]

This snail is also one of the rice field snail species traditionally eaten in Thailand.[19]

This article incorporates CC-BY-2.5 text from the reference[7] and public domain text from the reference[5]

• (in Japanese) Shiba N. (1935). 朝鮮に於けるマルタニシの分布に就いて "The distribution of Viviparus (Cipangopaludina) chinensis malleatus (REEVE) in Chosen". ヴヰナス The Venus 5(1): 17-22. record in Zasshi Kiji Sakuin.