Phacosoma

Phacosoma is a genus of small, marine gastropod mollusks belonging to the family Pyramidellidae. These snails are commonly known as pyramid snails or oplophorous snails. They are characterized by their elongated, turret-shaped shells, which are typically thin and fragile. The shell surface is often sculptured with axial ribs and spiral lines.

Members of the genus Phacosoma are found in shallow marine waters worldwide, inhabiting sandy or muddy substrates. They are micro-predators, feeding primarily on the eggs of other marine invertebrates, such as polychaete worms and bivalves. Their feeding strategy involves using a proboscis to pierce egg masses and extract the contents.

Reproduction in Phacosoma is typically sexual, with individuals releasing planktonic larvae that disperse before settling and metamorphosing into adult snails. The genus is relatively small, with a limited number of described species. Further research is ongoing to clarify the taxonomic relationships within Phacosoma and to better understand their ecological roles in marine ecosystems. Their small size and secretive nature can make them difficult to observe and study in their natural habitats.