Lycaeidae

The Lycaeidae are a family of air-breathing land snails, terrestrial pulmonate gastropod mollusks in the superfamily Pupilloidea. These snails are characterized by their small size, generally under 5mm in shell height, and their operculum, a horny plate that seals the shell aperture when the animal retracts.

Lycaeids are found primarily in Europe and surrounding regions, often inhabiting damp leaf litter, moss, and crevices in rocks or wood. Their shells are typically conical or turreted in shape, and are often sculptured with ribs or other surface features. The operculum is a key diagnostic feature, distinguishing them from other small snail groups.

The classification of Lycaeidae has undergone revisions, with some genera formerly placed in other families now included within Lycaeidae. This family is distinguished by specific anatomical characteristics of their reproductive and nervous systems. While small, they are a significant component of the microfauna in their habitats, contributing to decomposition and nutrient cycling. Further research is ongoing to clarify the evolutionary relationships and biogeography within this family.