Cyclostomatids

Cyclostomatids are a family of marine gastropod mollusks belonging to the order Caenogastropoda. They are characterized by their operculate snails, meaning they possess an operculum, a hard, horny or calcareous plate that seals the shell aperture when the animal retracts. This operculum serves as a protective defense against predators and desiccation. The shells of cyclostomatids are typically thick and heavy, often with a conical or turbinate shape. They are found in a wide range of marine environments, from shallow intertidal zones to deeper waters, and inhabit various substrates including rocky shores, sandy bottoms, and coral reefs. Their distribution is primarily in tropical and subtropical regions worldwide.

The diet of cyclostomatids varies, with many species being herbivores that graze on algae, while others are detritivores, feeding on decaying organic matter. Some may also be omnivorous. Reproduction in cyclostomatids generally involves separate sexes, with internal fertilization. The eggs are typically laid in gelatinous masses or capsules attached to the substrate, or in some cases, the female broods the young. The larval stages are planktonic, dispersing to new areas before settling and developing into juvenile snails. Fossil evidence indicates that cyclostomatids have a long evolutionary history, with their ancestors appearing in the fossil record from the Mesozoic Era. They are an ecologically significant group, contributing to the biodiversity and functioning of marine ecosystems.