Bellamya aeruginosa

Sinotaia aeruginosa (synonym: Bellamya aeruginosa) is a species of freshwater snail with a gill and an operculum, an aquatic gastropod mollusk in the family Viviparidae. It is widely distributed and common species in China and in northern Vietnam inhabiting various shallow freshwater habitats, where it can reach high densities. It is a keystone species in its habitat and can significantly affect water quality and phytoplankton communities. It is commonly used in Chinese cuisine. This species was described under the name Paludina aeruginosa by English conchologist Lovell Augustus Reeve in 1863. He noted that it he thought it 'very closely allied to Paludina quadrata'. Reeve's original text (the type description) reads as follows: The specific name aeruginosa derives from Latin aerūgō ('copper rust' or 'bronze rust'), referring to the green color of the shell. Later authors considered this taxon as a subspecies or form of Bellamya quadrata. It is generally classified as a species Sinotaia aeruginosa within the genus Sinotaia, although Chinese malacologists use the name Bellamya aeruginosa within the genus Bellamya. The species is found throughout China and Vietnam; indeed, S. aeruginosa is one of the most common species in China. It is common in the Yangtze River and Yellow River basins. The distribution of S. aeruginosa includes East China (Anhui, Fujian, Jiangsu, Jiangxi, Shandong, Shanghai, Zhejiang), Northeast China (Heilongjiang, Jilin, Liaoning), North China (Beijing, Hebei, Inner Mongolia, Shanxi, Tianjin), Northwest China (Ningxia, Shaanxi), Central China (Henan, Hubei, Hunan), Southwest China (Chongqing, Guizhou, Sichuan, Yunnan) and South China (Guangdong, Guangxi, Hainan). In Vietnam it is also common, but rarely reaches very high population densities. The type locality is 'China'. The species' distribution appears to have shrunk from the Middle Pleistocene to the Late Pleistocene, while a range expansion occurred in the Holocene. The height of the shell is 20–30 mm (0.79–1.18 in), with both sexes having identical shell dimensions. Adults snails have shell of greater height than width. The shells of newborn snails are 2.93–3.70 mm (0.115–0.146 in) long, and differ from those of adults in being wider than high. The snail including the shell has a weight of about 2.8 g. S. aeruginosa breathes with gills. The right tentacle is thickened in the male but not the female. The dry weight of composition of this species is as follows: 28.6% foot, 23.06% intestine, 9.78% gonad, 8.58% hepatopancreas, 29.98% other tissue. The diploid chromosome number of Sinotaia aeruginosa is 2n=16. S. aeruginosa inhabits rice paddies, lakes, pools, slow flowing rivers, streams, ditches, ponds, and canals called khlongs in Vietnam. It has a benthic lifestyle and lives mainly in shallow littoral areas, usually in soft mud rich in organic matter. It can actively glide over the sediment or bury into it. This species is not actively migrating, rather its dispersal appears to be caused passively by floods, animals (zoochory), and accidentally by humans. The species prefers water temperatures typical of subtropical habitats, e.g., 6 to 30.1 °C (42.8 to 86.2 °F) in Lake Tai.