Anisus

Anisus is a genus of freshwater air-breathing snails, aquatic pulmonate gastropod mollusks in the family Planorbidae, the ram's horn snails.

Description:

Snails in the genus Anisus are characterized by their small, discoidal or planispiral shells, meaning the shell is coiled in a flat spiral. The whorls are typically tightly coiled and the shell surface can be smooth or ornamented with fine growth lines. Like all planorbids, Anisus snails are sinistral, meaning the shell appears to be coiled in the opposite direction compared to most other snail shells.

Distribution:

Anisus species are primarily found in Europe and parts of Asia. They inhabit a variety of freshwater habitats, including ponds, lakes, ditches, and slow-flowing streams.

Ecology:

Anisus snails are generally herbivorous, feeding on algae, detritus, and other organic matter. They are an important food source for fish, amphibians, and other aquatic animals. As air-breathing snails, they regularly surface to breathe atmospheric air.

Species:

The genus Anisus comprises several species, with taxonomic classifications subject to ongoing revision. Some recognized species include:

• Anisus vortex (Linnaeus, 1758) - Vortex Ram's-horn Snail
• Anisus leucostoma (Millet, 1813)
• Anisus spirorbis (Linnaeus, 1758)

Conservation Status:

The conservation status of individual Anisus species varies depending on their distribution and the threats they face. Habitat loss, pollution, and climate change can all impact populations of freshwater snails. Some species may be locally threatened or endangered.

Relationship to Humans:

Anisus snails are generally not considered to be of significant economic importance to humans. However, they can play a role in the aquarium trade as decorative or scavenging snails. They can also serve as intermediate hosts for certain parasites, although this is not a widespread concern.