Rhabdopleura normani is a small, marine species of worm-shaped animal. It is a sessile

Sessility (zoology)

In zoology, sessility is a characteristic of animals which are not able to move about. They are usually permanently attached to a solid substrate of some kind, such as a part of a plant or dead tree trunk, a rock, or the hull of a ship in the case of barnacles. Corals lay down their own...

 suspension feeder, lives in clear water, and secrete

Secretion

Secretion is the process of elaborating, releasing, and oozing chemicals, or a secreted chemical substance from a cell or gland. In contrast to excretion, the substance may have a certain function, rather than being a waste product...

s tubes on the ocean floor.

Description

This species grows in colonies. Each individual achieves a length of 0.5 mm, with a total colony length of approximately 20 mm.

Located on the tentacles are lateral, frontal, and frontolateral ciliary bands. These are 8-13 μm in length and composed of cilia. In specimens collected in Bermuda, ciliated perforations were found. These ran down the length of the arms, in particular, between the bases of other tentacles laying adjacent.

Distribution

Rhabdopleura normani is widely distributed along the coastlines of the Bering Sea

Bering Sea

The Bering Sea is a marginal sea of the Pacific Ocean. It comprises a deep water basin, which then rises through a narrow slope into the shallower water above the continental shelves....

, Norwegian Sea

Norwegian Sea

The Norwegian Sea is a marginal sea in the North Atlantic Ocean, northwest of Norway. It is located between the North Sea and the Greenland Sea and adjoins the North Atlantic Ocean to the west and the Barents Sea to the northeast. In the southwest, it is separated from the Atlantic Ocean by a...

, Atlantic Ocean

Atlantic Ocean

The Atlantic Ocean is the second-largest of the world's oceanic divisions. With a total area of about , it covers approximately 20% of the Earth's surface and about 26% of its water surface area...

, and Mediterranean Sea

Mediterranean Sea

The Mediterranean Sea is a sea connected to the Atlantic Ocean surrounded by the Mediterranean region and almost completely enclosed by land: on the north by Anatolia and Europe, on the south by North Africa, and on the east by the Levant...

. It has also been found in Bermuda

Bermuda

Bermuda is a British overseas territory in the North Atlantic Ocean. Located off the east coast of the United States, its nearest landmass is Cape Hatteras, North Carolina, about to the west-northwest. It is about south of Halifax, Nova Scotia, Canada, and northeast of Miami, Florida...

.

Habitat

This species lives in colonies on the ocean floor. It has been found at depths ranging from 5 m to 896 m, but most commonly occurs between 100 m and 300 m.

Feeding

R. normani does not use mucus to capture food. Instead, it uses only a local reversal of a ciliary beat. It is also capable of rejecting unsuitable food particles employing several distinct methods of methods.

Reproduction

Both sexes live together in the colonies. Females have distinctive basally-coiled tubes in which they brood their eggs, each 200 μm in size. As these yolky eggs develop, they cleave radically, and become larvae. These larvae are ciliated, lecithropic, and oblong, acheiving a length of 400 μm. They can be identified in the following ways:

• They have a yellow coloration, covered with black spots
• A deep ventral depression is present
• There is a posterior adhesive organ and an anterior apical sensory organ
• The epitdermisan has consistent ciliation

The ventral depression is actually a glandular epitheliumis, as opposed to invaginating endoderm. The larval cocoon and adult tube are secreted from this depression.

Inside, the peritoneum of the coelomic cavities starts to disconnect from the main mass of the yolky mesenchyme cells. After breaking free, the larva then swims using its cilia.