Planorbella trivolvis
Planorbella trivolvis is a species of freshwater air-breathing snail, an aquatic pulmonate gastropod mollusk in the family Planorbidae, the ram's horn snails, or planorbids, which all have sinistral or left-coiling shells.
Description
All species within family Planorbidae have sinistral shells. The width of the shell of this species is up to 18 mm.Distribution
This pond snail is native to North America, from the Arctic areas of Canada all the way south to Florida. It has also been introduced in other parts of the world.Recent genetic analysis of western U.S. populations of Planorbella trivolvis found that most genetic variation occurs within and among local populations rather than between watersheds, and that geographic distance did not predict genetic distance — a pattern attributed to long-distance dispersal by migratory waterfowl.