Ringbuilders

Ringbuilders are a group of marine annelid worms belonging to the family Sabellidae. These fascinating creatures are commonly known as fan worms or feather duster worms due to the distinctive crown of feathery tentacles, called a radiolar crown, that extends from their anterior end. This radiolar crown serves a dual purpose: it is used for respiration, extracting oxygen from the water, and for filter feeding, capturing small food particles from the water column.

Ringbuilders construct tubes, typically made of secreted mucus and embedded sand grains or shell fragments, to protect their soft bodies. These tubes can be found attached to various substrates, including rocks, coral reefs, and even pilings. The size and appearance of the tube vary greatly depending on the species.

These worms are found in marine environments worldwide, inhabiting a wide range of habitats from shallow coastal waters to the deep sea. They play an important role in their ecosystems by contributing to biodiversity and serving as a food source for other marine animals. While some species are solitary, others may form aggregations. Their reproductive strategies often involve the release of gametes into the water column. Ringbuilders are a diverse family with hundreds of described species, each adapted to its specific ecological niche.