Panamic Fan Worm, Bispira monroi
Panamic Fan Worm, Bispira monroi. Underwater photograph taken in Bahía de Banderas, Puerta Vallarta, Jalisco, July 2026. Photograph and identification courtesy of Greg Timms, youtube.com/@CoralmasterdivesPuertoVallarta/videos.
Panamic Fan Worm, Bispira monroi. Underwater photograph taken in Zihuatanejo Bay, Guerrero, March 2018. Photograph courtesy of Ron Woheau, Zihuatanejo. Identification courtesy of Greg Timms, youtube.com/@CoralmasterdivesPuerto-Vallarta/videos.
Panamic Fan Worm, Bispira monroi. Underwater photograph taken in Zihuantanejo Bay, Guerrero, March 2020. Photograph courtesy of Ron Woheau, Zihuantanejo. Identification courtesy of Greg Timms, youtube.com/@CoralmasterdivesPuertoVallarta/videos.
Phylogeny: The Panamic Fan Worm, Bispira monroi (Hartman, 1961), is a member of the Sabellidae Family of Feather Duster Worms. The Bispira Genus is one of forty-one genera in the Sabellidae Family, and there are twenty-eight species in the Bispira Genus. The Sabellidae Family is currently undergoing much needed taxonomic revision. Additionally, many species in the Sabellidae Family have been introduced to multiple locations, making range a less valuable tool in determining species identification. Positive identification of species in this family is difficult. As a result many identifications are stopped at at the genus level. This species is also known as Monro’s Fan Worm.
Morphology: The Panamic Fan Worm has a crown-like funnel structure, on top of a thick, muddy, leathery tube, giving the animal a chalice-like shape. The crown is multi-layered with a heavily spiraled or coiled base. The radioles (tentacles) are neatly uniform, closely packed, and stiff. The 13 to 29 radioles gracefully curve inward to form a deep cup. The radioles are bright, translucent, creamy-white, with three rows of purple to reddish-brown bands. The bands do not have a uniform pattern, but they run in rings all the way around the plume. They have a “spikey” appearance, with the sharp creamy white tips of the radiolar pinnules pointing upward. This multi-layered “pinecone” structure is highly characteristic of the Bispira genus when it is fully expanded. Panamic Fan Worm bodies reach 3.4 cm (1.3 inches) in length and 2.0 mm to 4.0 mm in diameter. The radioles reach 1.7 cm (0.6 inches) in length.
Habitat and Distribution: Panamic Fan Worms emerge from rocks, rubble, coral, and sandy flats. They live from the intertidal zone, to depths of 61 m (200 feet). They are a subtropical to tropical Eastern Pacific species that are found in all Mexican waters of the Pacific Ocean, with the exception that they are absent from the west coast of the Baja Peninsula.
Diet: Panamic Fan Worms are suspension feeders, filtering plankton and organic matter from the passing currents, or by creating currents by use of the radioles.
Predators: Panamic Fan Worms can quickly withdraw into their tubes if they sense a change in light or water motion. This deters some predators. Predation of Panamic Fan Worms is poorly documented. Other species in the Bispira Genus are prey for crabs, fishes, gastropods and sea stars, who usually only nip off the radioles. Panamic Fan Worms can regrow new radioles in a matter of months.
Reproduction: Panamic Fan Worms reproduce primarily asexually by making clones of themselves, through fragmentation or fission. Sexual reproduction occurs through broadcast spawing, 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: Panamic Fan Worms are thought to be beneficial to coral reef habitats in that they help keep organic matter from smothering the coral animals. They provide habitat for tiny marine invertebrates, such as amphipods, bryozoans, copepods, and juvenile crabs. Otherwise, little is know about their relationship with other species.
Human Interactions: Panamic Fan Worms have a very limited impact on human activities. From a conservation perspective the Panamic Fan Worm has not been formally evaluated however they are fairly common, with a wide distribution, and should be consider to be of Least Concern.
Synonym: Distylidia monroi