Lister's river snail
Viviparus contectus
Lister's river snail is a large freshwater snail with a shell reaching up to 5 cm in height, characterized by seven strongly convex whorls and a very pointed apex. It is a prosobranch snail, possessing gills and an operculum that allows it to tightly seal its shell aperture. This species is ovoviviparous, meaning it gives birth to live young that have developed within the mother's body. It is typically found in stagnant or slow-moving waters with abundant vegetation and muddy substrates.
Details
Identification
Shell with a very pointed apex, deeply indented sutures, aperture pointed at the top, usually three reddish-brown spiral bands on a yellowish-green background.
Social behavior
Predominantly solitary, but occurs in high individual densities under favorable conditions.
Diet
Omnivore and filter feeder; feeds on periphyton, detritus, and can filter food particles from the water using mucus nets.
Hunting strategy
Passive grazing of surfaces and active filtering of the water column.
Spawning substrate
No substrate required as the species is live-bearing (ovoviviparous).
Overwintering
Overwinters buried in the mud at the bottom of the water body.
Ecology
Ecological role
Important decomposer in the ecosystem; contributes to nutrient remobilization and serves as prey for various vertebrates.
Natural predators
Cyprinid fish, waterfowl, muskrats, and larger crayfish.
Competitor species
Viviparus viviparus (River snail) in boundary habitats.
Ecosystem service
Water clarification through filtration and decomposition of organic material at the bottom of the water body.
Threats
River engineering, excessive eutrophication, and the draining of shallow water zones.
Scientific profile
Profile
Distinguishing features
The most important diagnostic feature is the very pointed apex, which distinguishes the species from Viviparus viviparus. Additionally, it possesses a clearly open, deep umbilicus and a horny operculum with concentric growth lines. The whorls are significantly more inflated than in related species.
Reproduction
Dioecious and ovoviviparous; females give birth to fully developed young after an internal development period of several months.