ciliated sponge

Sycon ciliatum, the ciliated sponge, is a small calcareous sponge in the family Sycettidae, widely distributed along the coasts of Europe and the North Atlantic. It grows as a slender, vase-shaped or cylindrical solitary body, typically 1–5 centimeters tall, with a distinctive fringe of long spicules surrounding the apical opening (osculum), which gives it its ciliated appearance. The sponge is white to pale yellow and is found attached to rocky substrates, algae, seagrass, shells, and pier pilings in shallow subtidal and lower intertidal zones. Sycon ciliatum is a filter feeder, drawing water through its porous body wall and extracting bacteria, phytoplankton, and organic particles. It is one of the most studied calcareous sponges and has been used extensively in developmental biology research due to its relatively simple body plan. The species is not assessed by the IUCN. Calcareous sponges in the class Calcarea, including Sycon, have been important in understanding the evolution of sponge body plans. Sycon ciliatum reproduces both sexually, releasing larvae that settle on available substrates, and asexually by budding. It is common and not considered threatened across its European coastal range. The species provides microhabitat for small invertebrates and forms part of the diverse encrusting community of rocky subtidal habitats.