Viviparus

Viviparus is a genus of freshwater snails, classified within the family Viviparidae. These snails are characterized by their operculum, a "door" that can seal the shell closed for protection against predators or desiccation. Viviparus species are found in rivers, lakes, and ponds across Europe, Asia, and North America (though some North American populations are introduced).

A key distinguishing feature of Viviparus snails, and the reason for the genus name (from the Latin vivus, alive, and pario, to bring forth), is their method of reproduction. Unlike many snails that lay eggs, Viviparus snails are viviparous, meaning they give birth to live young. The developing embryos are retained within the mother's pallial oviduct until they are relatively well-developed juveniles.

These snails are typically detritivores and grazers, feeding on decaying organic matter and algae. They play a role in aquatic ecosystems by consuming organic debris and contributing to nutrient cycling.

The shell of Viviparus species is typically conical and spiraled, varying in color from greenish-brown to dark brown. The size of the shell varies depending on the species and environmental conditions.

Due to their sensitivity to water quality, Viviparus snails can be used as bioindicators of environmental pollution. Their presence or absence, as well as their abundance and health, can provide valuable information about the health of aquatic ecosystems. Some Viviparus populations are also affected by habitat loss and competition from invasive species.