This species grows in colonies. Each individual achieves a length of 0.5 mm, with a total colony length of approximately 20 mm.[4][5]
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.[3]
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.[6][9]
R. normani uses a local reversal of a ciliary beat to capture food. It is also capable of rejecting unsuitable food particles employing several distinct methods.[3]
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:[4]
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 epidermis has consistent ciliation.
The ventral depression is actually a glandular epithelium, as opposed to invaginating endoderm. The larval cocoon and adult tube are secreted from this depression.[4]
Inside, the peritoneum of the coelomic cavities starts to disconnect from the main mass of the yolky mesenchymecells. After breaking free, the larva then swims using its cilia.[4]
^ abcdLester, Susan M. (1987-06-10). "Ultrastructure of adult gonads and development and structure of the larva of Rhabdopleura normani (Hemichordata: Pterobranchia)". Acta Zoologica. 69 (2): 95–109. doi:10.1111/j.1463-6395.1988.tb00906.x.
^ abStebbing, A. R. D. (1970). "The status and ecology of Rhabdopleura compacta (Hemichordata) from Plymouth". Journal of the Marine Biological Association of the United Kingdom. 50 (1): 209–221. doi:10.1017/S0025315400000722.
^Beli E, Aglieri G, Strano F, Maggioni D, Telford MJ, Piraino S, Cameron CB (2018) The zoogeography of extant rhabdopleurid hemichordates (Pterobranchia: Graptolithina), with a new species from the Mediterranean Sea. Invertebr Syst 32(1):100–110. doi:10.1071/IS17021
