seapen
Sea pens are a group of sessile, colonial cnidarians in the order Pennatulacea. They are soft-bodied octocorals that resemble quills or feathers, and they anchor themselves in soft marine sediments on the seafloor. A sea pen colony consists of a central stalk, or peduncle, which attaches to the substrate by a basal holdfast. From the peduncle extends a branching rachis that bears numerous feeding polyps (autozoids) and a few specialized reproductive or defensive polyps. When expanded, the tentacles of the feeding polyps capture plankton and detritus from the surrounding water. Sea pens can retract their polyps into the stalk for protection when disturbed.
Habitat and distribution: Sea pens are found worldwide in oceans from shallow subtidal zones to deep-sea environments.
Reproduction and life cycle: Reproductive strategies vary among species. Many sea pens are dioecious or hermaphroditic,
Ecology and conservation: Sea pens contribute to seabed habitat complexity, providing shelter for small invertebrates and
Taxonomy: Sea pens belong to the phylum Cnidaria, class Anthozoa, subclass Octocorallia, order Pennatulacea. They encompass