Rhabdopleura normani
Rhabdopleura normani is a small, marine species of worm-shaped animal known as a pterobranch. It is a sessile suspension feeder, lives in clear water, and secretes 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, Norwegian Sea, Atlantic Ocean, and Mediterranean Sea. It has also been found in Bermuda. Reported locations include: The widespread distribution of "Rhabdopleura normani" suggests a possible presence of cryptic diversity. 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. 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 radially, and become larvae. These larvae are ciliated, lecithotrophic, and oblong, achieving a length of 400 μm. They can be identified in the following ways: The ventral depression is actually a glandular epithelium, 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.