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Funiculina quadrangularis is often called the Tall Sea Pen. This marine invertebrate is in the phylum Cnidaria, the class Anthoza, the subclass Otocorallia, the order Pennatulacea, and the family Funiculinidae. Funiculina quadrangularis has an extremely wide distribution. It is found in the Atlantic, the Pacific, the Indian Ocean, and the Mediterranean Sea. The depth range is 20-2,000 m. (65.6-6,561.6 feet). Populations are found in coastal waters of various places, including Britain, Japan, and New Zealand.
Funiculina quadrangularis grows up to 2.1 m. (6.9 feet) in length. Each individual is composed of a group of soft-bodied polyps that are situated on a calcareous middle section. This section is stiffened; it is referred to as an axis or rachis. The axis of Funiculina quadrangularis is white, narrow, and square in cross-section. Each polyp has eight tentacles. The polyps are white or pink. They are located irregularly along the axis or in rows on some parts of it.
Funiculina quadrangularis frequently occurs in dense groups. It uses the tentacles to obtain plankton from the water column. The genders are separate. Male and female polypss are located in separate colonies on sea pens.
Funiculina quadrangularis is known to play host to Asteronyx loveni). This brittlestar uses its arms to cling to Funiculina quadrangularis. In addition, Funiculina quadrangularis serves as host to an isopod called Astacilla longicornis.
Eggs and fertilizing chemicals are released into the water so that reproduction can occur. After the eggs are fertilized, they develop into larvae called planulae. The planulae drift freely for a few days. Then they settle on the substrate.
These publications are references:
O. Ager, 2001. Tall sea pen, Funiculina quadrangularis. Marine Life Information Network.
Uk Marine SACS Project (August, 2002).
UK BAP (August, 2002).