Fan Worm Worth Seeing, Sabellastarte spectabilis

Fan Worm Worth Seeing, Sabellastarte spectabilis. Underwater photograph taken in coastal waters off Kawaihae, Hawaii, February 2020. Photographs and identification courtesy of Bob Hillis, Ivins, Utah.

Phylogeny: The Fan Worm Worth Seeing, Sabellastarte spectabilis (Grube, 1878) is a member of the Sabellidae Family of Feather-duster Worms. The Sabellastarte genus is one of forty-one genera in the Sabellidae Family, and there are eight species in the Sabellastarte genus. They are also  known as the Indian Fan Worm, and generically as a Feather Duster Worm. In Mexico they are called the Gusano Abanico Vistoso.

Morphology: The Fan Worm Worth Seeing has a well-developed crown of long filaments called radioles. The radioles circumscribe, and hide, the mouth. They are a variety of shades of brown, often with two or three darker bands on the radioles. They can, however, vary in color from white to almost black. The body is encased in a resilient leathery tube. The body consists of an anterior thorax and a posterior abdomen. Unlike most Fan Worms, this species lacks eyes, and therefore is less likely to retract when approached. The body of Fan Worm Worth Seeing, without the crown, can reach a maximum of 8.0 cm (3.1 inches) in length. The radioles can reach 6.3 cm (2.5 inches) in length.

Habitat and Distribution: Fan Worms Worth Seeing are found attached to pilings, rocks, rubble, coral, and even on sandy flats. Often, they are found in areas with significant water movement, but they are also found in calm silty water. They live subtidally, from depths of 1 m (3 feet) to 6 m (20 feet). The Fan Worm Worth Seeing is native to the Red Sea and the Indo-Pacific but it has spread to have almost global distribution in all tropical waters. They have a very limited distribution in Mexican waters, where they range from La Paz to the greater Los Cabos area in Baja California Sur.

Diet:  Fan Worms Worth Seeing are suspension feeders, filtering plankton and organic matter from the passing currents, or by creating currents by use of the radioles.

Predators: Fan Worms Worth Seeing are preyed upon by shrimp and fish, such as angelfish, butterflyfish,  triggerfish, and wrasse.

Reproduction: The Fan Worm Worth Seeing reproduced either asexually (through fragmentation) or sexually. Depending on the source, Fan Worms Worth Seeing are either gonochoric (male or female for life) or sequential hermaphrodites (changing sex with age). Reproduction is sexual, with external fertilization. The fertilized eggs drift as plankton before settling to the bottom as trochophore larvae, which then develop into adult worms.

Ecosystem Interactions:  The Fan Worm Worth Seeing is thought to be beneficial to coral reef habitats in that they help keep organic matter from smothering the coral animals. Otherwise, little is know about their relationship with other species, especially in regards to their non-native/invasive impacts.

Human Interactions: Fan Worms Worth Seeing are utilized by the aquarium trade. They also are considered to be fouling organisms- fouling ship hulls, pier pilings, pipelines, and other submerged infrastructure. Efforts to prevent their further spread has had  limited success. From a conservation perspective the Fan Worm Worth Seeing has not been formally evaluated however they have are common with a wide distribution and should be consider to be of Least Concern.

Synonyms:  Laonome punctata, Sabella grandis, Sabella indica, Sabella notata, Sabella spectabilis,  Sabellastarte indica, and Sabellastarte indica quinquevalens.