Coenenchyme is the common tissue that surrounds and links the polyps in octocorals. It consists of mesoglea penetrated by tubes (solenia) and canals of the gastrodermis and contains sclerites, microscopic mineralised spicules of silica or of calcium carbonate. The outer layer of the coenenchyme is made of columnar or squamous epithelial cells, and can be covered in microvilli. [1] The stiff projecting portion of coenenchyme that surrounds each polyp is usually reinforced by modified sclerites and is called the calyx, [2] a term borrowed from botany. The solenia circulate nutrients throughout the coenenchyme. Coenosarc is an alternative name. [3]
Sea pens are colonial marine cnidarians belonging to the order Pennatulacea. There are 14 families within the order; 35 extant genera, and it is estimated that of 450 described species, around 200 are valid. Sea pens have a cosmopolitan distribution, being found in tropical and temperate waters worldwide, as well as from the intertidal to depths of more than 6100 m. Sea pens are grouped with the octocorals, together with sea whips (gorgonians).
The sea pansy, Renilla reniformis, is a species of colonial cnidarian in the family Renillidae, part of an octocoral subclass of Anthozoa that inhabit an expansive range of environments. It is native to warm continental shelf waters of the Western Hemisphere. It is frequently found washed ashore on North East Florida beaches following northeasterly winds or rough surf conditions. It also can often be found living intertidally completely buried in the sand. Its predator is the striped sea slug, Armina tigrina.
Alcyonacea, or soft corals, are an order of corals. In addition to the fleshy soft corals, the order Alcyonacea now contains all species previously known as "gorgonian corals", that produce a more or less hard skeleton, though quite different from "true" corals (Scleractinia). These can be found in suborders Holaxonia, 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 subclass of Anthozoa comprising around 3,000 species of water-based 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.
Blue coral is a species of colonial coral. It is the only octocoral known to produce a massive skeleton. This skeleton is formed of aragonite, similar to that of scleractinia. Individual polyps live in tubes within the skeleton and are connected by a thin layer of tissue over the outside of the skeleton.
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.
Leptogorgia virgulata, commonly known as the sea whip or colorful sea whip, is a species of soft coral in the family Gorgoniidae.
Iciligorgia schrammi, common names deepwater sea fan and black sea fan is a species of gorgonian sea fan in the family Anthothelidae. It is found in tropical parts of the Atlantic Ocean. This species was first described in 1870 by the French naturalist Édouard Placide Duchassaing de Fontbressin.
Leptogorgia hebes, commonly known as the regal sea fan or false sea fan, is a species of soft coral in the family Gorgoniidae. It was formerly included in the genus Lophogorgia but that genus has been dismantled.
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.
Dendronephthya hemprichi is a common soft coral found from Red Sea to Western Pacific. It is usually pink or orange with transparent trunk and it grows up to 70 cm. It exists at 30° N latitude. The smallest unit of this coral, like all other corals, is a polyp. This particular species of the Dendronephthya has the ability to reproduce sexually and asexually through broadcast spawning and clonal propagation, respectively.
Swiftia pallida is a species of gorgonian-type octocoral in the family Plexauridae sometimes known as the northern sea fan. At one time it was considered to be a subspecies of Swiftia rosea.
Eunicea is a genus of gorgonian-type octocorals in the family Plexauridae. These branched octocorals typically have knobby protuberances from which the polyps protrude. They are often stiffened by purple sclerites and some colonies, in brightly lit back-reef areas are purple, though most colonies are brown or grey. The polyps in some species are large and feathery in appearance. The growth of these corals is rapid and they can be kept in a reef aquarium.
Paramuricea clavata, the violescent sea-whip, is a species of colonial soft coral in the family Plexauridae. It is found in shallow seas of the north-eastern Atlantic Ocean and the north-western Mediterranean Sea as well as Ionian Sea. This species was first described by the French naturalist Antoine Risso in 1826.
Leptogorgia sarmentosa is a species of colonial soft coral, a sea fan in the family Gorgoniidae. It is native to the eastern Atlantic Ocean and the western Mediterranean Sea, with a single find in the eastern Mediterranean.
Alcyonium coralloides, commonly known as false coral, is a colonial species of soft coral in the family Alcyoniidae. It is native to the northeastern Atlantic Ocean and the Mediterranean Sea. In the former location it generally grows as sheets or small lobes but in the latter it is parasitic and overgrows sea fans.
Eunicella singularis, the white gorgonian, is a species of colonial soft coral, a sea fan in the family Gorgoniidae. It is found in the western Mediterranean Sea, Adriatic Sea and Ionian Sea. It was first described in 1791 by the German naturalist Eugenius Johann Christoph Esper.
Taiaroa is a genus of deep-water, solitary marine octocorals in the family Taiaroidae. Taiaroa is monotypic in the family Taiaroidae and contains a single species, Taiaroa tauhou. The species was first described by the marine zoologists Frederick M. Bayer and Katherine Margaret Muzik in 1976. The scientific name derives from "Taiaroa", the submarine canyon off New Zealand in which the first specimens were found and "tauhou", the Maori word for "strange".
Pseudoplexaura porosa, commonly known as the porous sea rod or the porous false plexaura, is a species of gorgonian-type colonial octocoral in the family Plexauridae. It is native to the Caribbean Sea and the Gulf of Mexico.
Clavularia crassa is a species of colonial soft coral in the family Clavulariidae. It is found in the eastern Atlantic Ocean and the Mediterranean Sea. It was first described in 1848 by the French zoologist Henri Milne-Edwards from a specimen collected off the coast of Algeria.