serpulid

Serpulids are a family of marine polychaete annelids (Serpulidae) that live in calcareous tubes secreted by their bodies. They are sessile, tube-dwelling worms that attach to hard substrates such as rocks, shells, coral, and man-made structures across the world’s oceans, from shallow intertidal zones to the deep sea. The worm’s body typically extends from the tube only when feeding or after a disturbance.

A defining feature of serpulids is their cephalic crown of feathery, ciliated tentacles called radioles, which form a circlet used for respiration and filter feeding. The radioles capture suspended particles from the water, and mucus or ciliary action transports food to the mouth. Many serpulids build conical or cylindrical tubes made of calcareous material, sometimes with an operculum or lid that can seal the tube opening when the worm retracts inside.

Serpulids play ecological roles as reef- and fouling-community members, contributing to habitat structure and serving as prey for other invertebrates and fish. They reproduce by releasing free-swimming larvae that eventually settle and secrete their tubes. Larval development is typically planktonic for a period before settlement.

In paleontological contexts, serpulid tubes fossilize well and provide records of ancient marine environments. Some species, especially within the genus Hydroides, are well known as prolific biofoulers on ships, piers, and aquaculture equipment, where they can impact infrastructure and ecosystems.