The Sea Pen – Cavernularia obesa is a fascinating marine organism belonging to the class Octocorallia, specifically the order Scleralcyonacea and family Veretillidae. It is known for its unique morphology and its role within the marine food web.
Description & Characteristics
The Sea Pen is a colonial organism, meaning it consists of many individual polyps living together. It derives its name from its resemblance to a quill pen, with a long, cylindrical stalk and a feathery crown of polyps at the top. The Cavernularia obesa can grow to a maximum size of around 30 cm in length. Its color varies depending on the environment and can range from shades of white, pink, or even brown.
Habitat and Occurrence
The Cavernularia obesa is typically found in Subtidal, sublittoral, infralittoral, deep zone of the oceans from the lower limit of the intertidal zone (intertidal) to the shelf edge at about 200 m water depth. It prefers soft, sandy, or muddy substrates. These environments are classified as neritic, encompassing the coastal waters of the ocean. You can encounter the Sea Pen in various regions around the world, inhabiting a range of marine zones that contribute to its widespread distribution.
Taxonomy
The Cavernularia obesa belongs to the class Octocorallia, which includes a diverse group of colonial animals. It is further classified within the order Scleralcyonacea, an order known for their distinctive skeletal structures, and the family Veretillidae, known for their often large and robust forms.
Feeding
The Cavernularia obesa is a specialized feeder, primarily consuming plankton. These tiny organisms are captured by the polyps’ tentacles, which are covered in stinging cells called nematocysts. These nematocysts paralyze and then transport the plankton into the polyps’ mouths, where they are digested. The Sea Pen plays an important role in the marine food web, contributing to the overall balance of the ecosystem.
Image References