Collared Sand Anemone

Actinostella flosculifera

The Collared Sand Anemone, Actinostella flosculifera, is a sea anemone species in the family Actiniidae. It is typically found in shallow waters of the tropical and subtropical Atlantic Ocean, often buried in sediment with only its oral disc visible. The disc, up to 7 cm in diameter, features four whorls of retractable tentacles surrounding a funnel-shaped mouth. The disc's coloration, which includes shades of beige, pinkish, brown, or grey, allows it to blend seamlessly with its surroundings. The tentacles are translucent and may have white spots. This anemone is distributed widely across the Atlantic, from the Canary Islands and Madeira to the Bahamas, Bermuda, and down to Brazil. It inhabits sandy, gravelly, or silty areas, often in seagrass meadows and lagoon reef flats with minimal wave action, at depths up to about 5 meters. During the day, the tentacles contract, and the collar expands to maximize sunlight exposure for the symbiotic zooxanthellae within its tissues, aiding photosynthesis. At night, the tentacles extend to capture plankton and organic particles. The anemone's diet primarily includes plankton and organic matter, supplemented by the digestion of its symbiotic zooxanthellae. Reproduction involves the release of gametes into the coelenteron, with the resulting zygote developing into a planktonic planula larva before settling. The conservation status of this species has not been evaluated.