| Narella | |
|---|---|
 | |
| Narella bowersi | |
Scientific classification  | |
| Domain: | Eukaryota |
| Kingdom: | Animalia |
| Phylum: | Cnidaria |
| Class: | Octocorallia |
| Order: | Alcyonacea |
| Family: | Primnoidae |
| Genus: | Narella Gray, 1870 |
Narella (Gray, 1870) is a genus of deep-sea soft corals in the family Primnoidae (Milne Edwards, 1857). [1] They are sessile, bottom-dwelling organisms that can be found in all ocean basins, having cosmopolitan distribution. [2] They have a branching appearance.
The name Narella is believed to be derived from the latin nares, meaning nostril, due to the resemblance of the rows of polyps to small noses. [3]
The present understanding of Narella and its members was only established in the late 20th century. Prior to that, many members of Narella were categorized into other genera. While the genus itself was described in 1870 by John Edward Gray, [4] the first species in the genus was described in 1860, Primnoa regularis (now recognized as Narella regularis). [5] In 1887 several new species of Narella were discovered by Edward Wright and Théophile Studer, but were described as members of new genera Stachyodes and Calypterinus. [6] [7] [8] Between 1906 and 1919 many new species of Narella were discovered, though many were described as members of Stachyodes or Calypterinus. It was only in 1951 that Frederick Bayer synonymized these genera with Narella, establishing the former as junior synonyms of the latter. [9]
Narella is the most species-rich genus in Primnoidae. [10] They are found worldwide, with species occurring in the Atlantic, the Pacific, the Hawaiian Islands, the Indian Ocean, the Galápagos, and off the coast of Antarctica. [11] While there have been a few species that are found in multiple regions, in general each region has a distinct group of sympatric species. This, along with Narella's high rate of adaptive radiation has led to researchers believing it to have many undiscovered species. [3]
There are over 50 recognized species of Narella, but its type taxon is Narella regularis . Narella are distinguished from other members of Primnoidae by their conspicuous polyps which have very distinct large scales, also called sclerites. Most species of Narella have 16 - 18 sclerites that are always arranged in pairs. Polyps in members of Primnoidae are covered at the tip by opercular scales. In Narella, these eight opercular scales are paired together, giving them a symmetrical appearance. Physical differences amongst individual species of Narella primarily involve the shape and texture of the scales. These characteristics are difficult to identify in the field thus most broader identification guides focus on branching instead. [10]
The axis of corals in this genus are made of aragonite, while their spicules are made of high Mg calcite. [12] They anchor themselves to hard substrates using calcareous discoid holdfasts. [2]
The following are species currently recognized in the genus. [1]
Alcyonacea are an order of sessile colonial cnidarians that are found throughout the oceans of the world, especially in the deep sea, polar waters, tropics and subtropics. Whilst not in a strict taxonomic sense, Alcyonacea are commonly known as soft corals. The term "soft coral" generally applies to organisms in the two orders Pennatulacea and Alcyonacea with their polyps embedded within a fleshy mass of coenenchymal tissue. Consequently, the term "gorgonian coral" is commonly handed to multiple species in the order Alcyonacea that produce a mineralized skeletal axis composed of calcite and the proteinaceous material gorgonin only and corresponds to only one of several families within the formally accepted taxon Gorgoniidae (Scleractinia). These can be found in order Malacalcyonacea (taxonomic synonyms of include : Alcyoniina, Holaxonia, Protoalcyonaria, Scleraxonia, and Stolonifera. They are sessile colonial cnidarians that are found throughout the oceans of the world, especially in the deep sea, polar waters, tropics and subtropics. Common names for subsets of this order are sea fans and sea whips; others are similar to the sea pens of related order Pennatulacea. Individual tiny polyps form colonies that are normally erect, flattened, branching, and reminiscent of a fan. Others may be whiplike, bushy, or even encrusting. A colony can be several feet high and across, but only a few inches thick. They may be brightly coloured, often purple, red, or yellow. Photosynthetic gorgonians can be successfully kept in captive aquaria.
Octocorallia is a class of Anthozoa comprising over 3,000 species of marine organisms formed of colonial polyps with 8-fold symmetry. It includes the blue coral, soft corals, sea pens, and gorgonians within three orders: Alcyonacea, Helioporacea, and Pennatulacea. These organisms have an internal skeleton secreted by mesoglea and polyps with eight tentacles and eight mesentaries. As with all Cnidarians these organisms have a complex life cycle including a motile phase when they are considered plankton and later characteristic sessile phase.
Acanella is a genus of deep sea bamboo coral of the family Isididae. Acanella are mainly studied and found in Hawaii, they are able to survive in high-flow sites and are preyed upon by nudibranch mollusks. It has a high fecundity and small size that allows high dispersal and recruitment; however, it has been classified as a vulnerable marine organism due to its vulnerability to bottom fishing gear. It contains the following species:
Scleraxonia is a suborder of corals, a member of the phylum Cnidaria.
Coralliidae, also known as precious corals, is a taxonomic family of soft corals belonging to the suborder Scleraxonia of the phylum Cnidaria. These sessile corals are one of the most dominant members of hard-bottomed benthic environments such as seamounts, canyons and continental shelves. From this coral family results 69 descendants in which each species plays a key role in forming habitats for a variety of marine species.
Holaxonia is a suborder of soft corals, a member of the phylum Cnidaria. Members of this suborder are sometimes known as gorgonians and include the sea blades, the sea fans, the sea rods and the sea whips. These soft corals are colonial, sessile organisms and are generally tree-like in structure. They do not have a hard skeleton composed of calcium carbonate but have a firm but pliable, central axial skeleton composed of a fibrous protein called gorgonin embedded in a tissue matrix, the coenenchyme. In some genera this is permeated with a calcareous substance in the form of fused spicules. Members of this suborder are characterized by having an unspiculated axis and often a soft, chambered central core. The polyps have eight-fold symmetry and in many species, especially in the families Gorgoniidae and Plexauridae, contain symbiotic photosynthetic algae called zooxanthellae. These soft corals are popular in salt water aquaria.
Gorgoniidae is a family of soft corals, a member of the subclass Octocorallia in the phylum Cnidaria. Nearly all the genera and species are native to the east and west coasts of America.
Melithaea is a genus of octocorals in the family Melithaeidae. Members of the genus are commonly known as fan corals and are found in the tropical Indo-Pacific region. The type species is Melithaea ochracea.
Primnoa(Lamororux, 1812) also known as red tree coral, is a genus of soft corals and the type genus of the family Primnoidae (Milne Edwards, 1857). They are sessile, benthic cnidarians that can be found in the North Pacific, North Atlantic, and Subantarctic South Pacific, and its members often play a vital ecological role as keystone species within their environment as a habitat and refuge for the megafauna that also inhabit those regions. This, in combination with their slow growth, makes the increasing disturbance to their habitats caused by fishing activities particularly impactful and difficult to recover from.
Primnoidae is a family of soft corals.
Plexauridae is a family of marine colonial octocorals in the phylum Cnidaria. Members of this family are found in shallow tropical and subtropical seas. Many species contain symbiotic photosynthetic protists called zooxanthellae.
Ellisella, commonly known as sea whip, is a genus of soft coral in the family Ellisellidae.
Chrysogorgia is a genus of soft corals in the family Chrysogorgiidae.
Callogorgia is a genus of deep sea corals that are ideally suited to be habitats for different organisms. They reproduce both sexually and asexually, clinging to the hard substrate of the ocean during their maturation process. Callogorgia are found at depths ranging from 750-8200 feet in the Gulf of Mexico, Pacific Ocean and the Caribbean Sea. An array of organisms have relationships with Callogorgia, including brittle stars, cat sharks, and copepods. The nature of these relationships are often commensal, with Callogorgia providing a habitat for the organisms.
Callogorgia elegans is a species of soft corals in the family Primnoidae. It is found in the north-western Pacific Ocean. Like other coral species, C. elegans is bottom-dwelling and sessile, or immobile.
Briareum is a genus of soft corals in the family Briareidae. The coral is cultivated by aquarium owners for its fluorescing polyps, which reveal themselves under actinic light. The genus is in need of extensive examination, as many specimens sold by marketers display unique and similar characteristics, but are often labeled as one species, Pachyclavularia violacea.
Primnoeides is a genus of Cnidaria in the family Primnoidae.
Swiftia comauensis species of gorgonian-type octocoral in the family Plexauridae, only found in the Comau fiords of Huinay in the Hualaihué province of the region of Los Lagos, Chile.
Paracalyptrophora is a genus of corals belonging to the family Primnoidae.
Convexella is a genus of corals belonging to the family Primnoidae, first described by Frederick Bayer in 1996.
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