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Physella acuta

Physella acuta is a species of small, air-breathing freshwater snail in the family Physidae of North American origin. Like other physids, P. acuta presents a sinistral (left-coiling) shell as well as a unique set of muscles called the physid musculature that allows it to rapidly twist the shell as a defence mechanism. Physella acuta is invasive outside its native range. Its first introduction outside North America likely occurred through the 18th-century cotton trade to Europe, with later spread mainly through the aquarium trade. The species can occupy diverse freshwater habitats and tolerates polluted as well as oxygen-poor environments. Due to its high reproductive rate and tolerance to habitat degradation, it frequently outcompetes native snail species. In aquariums, P. acuta is usually introduced through ornamental plants and can become a "nuisance snail" due to its rapid reproduction. However, a controlled population can help clean up organic leftovers and control algae. (Full article...)

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