''Rhabdopleura normani'' is a small, marine species of worm-shaped animal known as a pterobranch. It is a

sessile Sessility, or sessile, may refer to: * Sessility (motility), organisms which are not able to move about * Sessility (botany), flowers or leaves that grow directly from the stem or peduncle of a plant * Sessility (medicine), tumors and polyps that ...

suspension feeder, lives in clear water, and

secrete 440px Secretion is the movement of material from one point to another, such as a secreted chemical substance from a cell or gland. In contrast, excretion is the removal of certain substances or waste products from a cell or organism. The classical ...

s tubes on the

ocean floor The seabed (also known as the seafloor, sea floor, ocean floor, and ocean bottom) is the bottom of the ocean. All floors of the ocean are known as 'seabeds'. The structure of the seabed of the global ocean is governed by plate tectonics. Most of ...

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 ) , anthem = "God Save the King" , song_type = National song , song = "Hail to Bermuda" , image_map = , map_caption = , image_map2 = , mapsize2 = , map_caption2 = , subdivision_type = Sovereign state , subdivision_name = , es ...

, 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 The Norwegian Sea ( no, Norskehavet; is, Noregshaf; fo, Norskahavið) is a marginal sea, grouped with either the Atlantic Ocean or the Arctic Ocean, northwest of Norway between the North Sea and the Greenland Sea, adjoining the Barents Sea to ...

Atlantic Ocean The Atlantic Ocean is the second-largest of the world's five oceans, with an area of about . It covers approximately 20% of Earth's surface and about 29% of its water surface area. It is known to separate the " Old World" of Africa, Europe ...

, and

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

. It has also been found in

. Reported locations include: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. * North Atlantic basin, including the

North Sea The North Sea lies between Great Britain, Norway, Denmark, Germany, the Netherlands and Belgium. An epeiric sea, epeiric sea on the European continental shelf, it connects to the Atlantic Ocean through the English Channel in the south and the ...

Barents Sea The Barents Sea ( , also ; no, Barentshavet, ; russian: Баренцево море, Barentsevo More) is a marginal sea of the Arctic Ocean, located off the northern coasts of Norway and Russia and divided between Norwegian and Russian territo ...

* Greenland Sea *

Labrador Sea The Labrador Sea (French: ''mer du Labrador'', Danish: ''Labradorhavet'') is an arm of the North Atlantic Ocean between the Labrador Peninsula and Greenland. The sea is flanked by continental shelves to the southwest, northwest, and northeast. It ...

* Bay of Biscay *

Celtic Sea The Celtic Sea ; cy, Y Môr Celtaidd ; kw, An Mor Keltek ; br, Ar Mor Keltiek ; french: La mer Celtique is the area of the Atlantic Ocean off the southern coast of Ireland bounded to the east by Saint George's Channel; other limits includ ...

Azores ) , motto =( en, "Rather die free than subjected in peace") , anthem= ( en, "Anthem of the Azores") , image_map=Locator_map_of_Azores_in_EU.svg , map_alt=Location of the Azores within the European Union , map_caption=Location of the Azores wi ...

South Atlantic The Atlantic Ocean is the second-largest of the world's five oceans, with an area of about . It covers approximately 20% of Earth's surface and about 29% of its water surface area. It is known to separate the " Old World" of Africa, Europe an ...

, including the

Argentine Sea The Argentine Sea ( es, Mar Argentino) is a marginal sea of the Atlantic Ocean adjacent to the southern tip of South America. It ranges from the mouth of the estuary of the Río de la Plata in the north (35th parallel south) to the Isla de los ...

* Fiji *

Antarctic Ocean The Southern Ocean, also known as the Antarctic Ocean, comprises the southernmost waters of the World Ocean, generally taken to be south of 60° S latitude and encircling Antarctica. With a size of , it is regarded as the second-small ...

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'' uses a local reversal of a ciliary beat to capture food. 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 Oviparous animals are animals that lay their eggs, with little or no other embryonic development within the mother. This is the reproductive method of most fish, amphibians, most reptiles, and all pterosaurs, dinosaurs (including birds), and m ...

, and oblong, achieving 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 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. 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.

References

External links

Images
{{Taxonbar, from=Q2325478

normani Normani Kordei Hamilton ( ; born May 31, 1996) is an American singer and dancer. She auditioned as a solo act for the American television series ''The X Factor'' in 2012, after which she became a member of the girl group Fifth Harmony, which wen ...

Fauna of the Atlantic Ocean Fauna of the Mediterranean Sea Fauna of the Pacific Ocean Animals described in 1869 Taxa named by George Allman (natural historian)