Cnidaria is a phylum under kingdom Animalia containing over 11,000 species of aquatic animals found both in freshwater and marine environments, including jellyfish, hydroids, sea anemone, corals and some of the smallest marine parasites. Their distinguishing features are a decentralized nervous system distributed throughout a gelatinous body and the presence of cnidocytes or cnidoblasts, specialized cells with ejectable flagella used mainly for envenomation and capturing prey. Their bodies consist of mesoglea, a non-living jelly-like substance, sandwiched between two layers of epithelium that are mostly one cell thick.
A cnidocyte is an explosive cell containing one large secretory organelle called a cnidocyst that can deliver a sting to other organisms. The presence of this cell defines the phylum Cnidaria. Cnidae are used to capture prey and as a defense against predators. A cnidocyte fires a structure that contains a toxin within the cnidocyst; this is responsible for the stings delivered by a cnidarian.
Pelagia noctiluca is a jellyfish in the family Pelagiidae and the only currently recognized species in the genus Pelagia. It is typically known in English as the mauve stinger, but other common names are purple-striped jelly, purple stinger, purple people eater, purple jellyfish, luminous jellyfish and night-light jellyfish. In Greek, pelagia means "(she) of the sea", from pelagos "sea, open sea"; in Latin noctiluca is the combining form of nox, "night"", and lux, "light"; thus, Pelagia noctiluca can be described as a marine organism with the ability to glow in the dark (bioluminescence). It is found worldwide in tropical and warm temperate seas, although it is suspected that records outside the North Atlantic region, which includes the Mediterranean and Gulf of Mexico, represent closely related but currently unrecognized species.
Chrysaora is a genus of jellyfish, commonly called the sea nettles, in the family Pelagiidae. The origin of the genus name Chrysaora lies in Greek mythology with Chrysaor, brother of Pegasus and son of Poseidon and Medusa. Translated, Chrysaor means "he who has a golden armament."
The black sea nettle, sometimes informally known as the black jellyfish, is a species of jellyfish that can be found in the waters of the Pacific Ocean off North America. Its range is thought to be from Monterey Bay in the north, down to southern Baja California and Mexico, though there are reports of sightings as far north as British Columbia. The initial acknowledgment of the species occurred in 1997, after large groups were found on the Pacific coast.
Chrysaora hysoscella, the compass jellyfish, is a common species of jellyfish that inhabits coastal waters in temperate regions of the northeastern Atlantic Ocean, including the North Sea and Mediterranean Sea. In the past it was also recorded in the southeastern Atlantic, including South Africa, but this was caused by confusion with close relatives; C. africana, C. fulgida and an undescribed species tentatively referred to as "C. agulhensis".
The Pacific sea nettle, or West Coast sea nettle, is a widespread planktonic scyphozoan cnidarian—or medusa, “jellyfish” or “jelly”—that lives in the northeastern Pacific Ocean, in temperate to cooler waters off of British Columbia and the West Coast of the United States, ranging south to México. The Pacific sea nettle earned its common name in-reference to its defensive, ‘nettle’-like sting; much like the stinging nettle plant, the sea nettle’s defensive sting is often irritating to humans, though rarely dangerous.
Chrysaora colorata (Russell), commonly known as the purple-striped jelly, is a species of jellyfish that exists primarily off the coast of California from Bodega Bay to San Diego. The bell (body) of the jellyfish is up to 70 cm (2.3 ft) in diameter, typically with a radial pattern of stripes. The tentacles vary with the age of the individual, consisting typically of eight marginal long dark arms, and four central frilly oral arms. It is closely studied by scientists due to not much being known about their eating habits. A 15-foot-long specimen has been seen.
Chrysaora melanaster, commonly known as the northern sea nettle or brown jellyfish, is a species of jellyfish native to the northern Pacific Ocean and adjacent parts of the Arctic Ocean. It is sometimes referred to as a Pacific sea nettle, but this name is also used for C. fuscescens; the name Japanese sea nettle was also used for this species, but that name now exclusively refers to C. pacifica. Although jellyfish kept in public aquariums sometimes are referred to as C. melanaster, this is the result of the historical naming confusion and these actually are C. pacifica.
Sea anemones are a group of predatory marine invertebrates constituting the order Actiniaria. Because of their colourful appearance, they are named after the Anemone, a terrestrial flowering plant. Sea anemones are classified in the phylum Cnidaria, class Anthozoa, subclass Hexacorallia. As cnidarians, sea anemones are related to corals, jellyfish, tube-dwelling anemones, and Hydra. Unlike jellyfish, sea anemones do not have a medusa stage in their life cycle.
Chrysaora pacifica, commonly named the Japanese sea nettle, is a jellyfish in the family Pelagiidae. This common species is native to the northwest Pacific Ocean, including Japan and Korea, but it was formerly confused with the larger and more northerly distributed C. melanaster. As a consequence, individuals kept in public aquariums have often been mislabelled as C. melanaster. The medusae of C. pacifica typically has a bell with a diameter of 15–21 cm (5.9–8.3 in). Its sting is strong and can be dangerous to humans.
Chrysaora helvola is a jellyfish in the family Pelagiidae. Although still recognized as a valid species by the World Register of Marine Species, its taxonomic history is confusing and recent reviews of the genus have not recognized it.
Chrysaora chinensis, or the Indonesian sea nettle, is a species of jellyfish in the family Pelagiidae. It is native to the central Indo-Pacific region and its sting is considered dangerous.
Chrysaora lactea is a species of sea nettle in the family Pelagiidae. This jellyfish has a bell diameter of up to 25 cm (10 in), and it is native to the Atlantic coast of South America. It has also been reported from the Caribbean region, but genetic studies indicate that this population is closer to C. chesapeakei. A comprehensive taxonomic review is necessary to resolve this matter.
The South American sea nettle is a species of jellyfish from the family Pelagiidae. It is found from the Pacific coast of Peru, south along Chile's coast to Tierra del Fuego, and north along the Atlantic coast of Argentina, with a few records from Uruguay. Despite its common name, it is not the only sea nettle in South America. For example, C. lactea is another type of sea nettle in this region. Historically, C. plocamia was often confused with C. hysoscella, a species now known to be restricted to the northeast Atlantic. C. plocamia is a large jellyfish, up to 1 m in bell diameter, although most mature individuals only are 25–40 cm (10–16 in).
Chrysaora fulgida, the Benguela compass jelly, is a species of jellyfish in the family Pelagiidae. Found in the southeastern Atlantic Ocean along the western coast of South Africa, its taxonomy has historically caused considerable confusion. Like other sea nettles, its sting is painful, but not generally dangerous unless there is an allergic reaction to the venom.
Chrysaora africana, the purple compass jelly, is a species of jellyfish from the family Pelagiidae. Found in the southeastern Atlantic Ocean from Gabon to the western coast of South Africa, its taxonomy has historically caused considerable confusion. Like other sea nettles, its sting is painful, but not generally dangerous unless there is an allergic reaction to the venom.
Chrysaora chesapeakei is a sea nettle from the family Pelagiidae. It was shown to be a distinct species from Chrysaora quinquecirrha in 2017. Since then, it is also commonly known as the bay nettle. It is mainly found in the Chesapeake Bay and along the East Coast of the United States.
Chiropsella bronzie is a species of box jellyfish. It is considered much less of a threat to humans than some of its relatives. The species was described in 2006, and is one of four species in the genus Chiropsella. Chiropsella bronzie can be found in shallow waters off the coast of Queensland, Australia.
Cyanea fulva, the Atlantic lion's mane jellyfish, is a species of jellyfish found along the Mid-Atlantic coastal region of the United States. C. fulva are commonly noted as being about two inches in diameter and smaller than C. capillata, however, larger than C. versicolor, a co-occurring close species. One distinctive feature present in mature C. fulva populations is their four mouth-part tentacles, containing a cinnamon color with the center of the main cavity being darker. At a young age, these jellyfish can have three appendages but often gain a fourth at more developed life cycle stages. C. fulva are also known for having less folds compared to C. arctica but more folds compared to C. versicolor. These folds are described as being remarkably thin and deciduous.
