Sycon Sponge

The sycon sponge (Sycon ciliatum) is a small, vase-shaped calcareous sponge of cold North Atlantic waters. Sponges are among the simplest animals: they have no organs or true tissues, yet they are the best clue we have to how animals began.

🧬 Field Guide Specimen: Open Sycon Sponge in the CRV Science Field Guide to log the specimen, see its place among the Metazoa lineages in the Cladogram Explorer, and test your recall in the Red List conservation game.

Cells called choanocytes, each with a beating flagellum surrounded by a collar of microvilli, line internal chambers and drive water through pores. They trap bacteria and fine particles from the current. The collar cell is strikingly similar to the single-celled choanoflagellates, the closest living relatives of animals.

Sycon builds spicules of calcium carbonate that support the body and bristle around the opening. Its body plan, with canals running radially to the central cavity, is called syconoid and is more complex than the simple tube of the lattice sponge.

Sponges can disaggregate into cells and reassemble, and their cells are flexible in what they can become. Comparing sponge genomes with those of other animals helps reconstruct the genes present in the earliest animals. See Evolution.