Aurelia | |
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Adult Aurelia aurita medusa | |
Scientific classification | |
Domain: | Eukaryota |
Kingdom: | Animalia |
Phylum: | Cnidaria |
Class: | Scyphozoa |
Order: | Semaeostomeae |
Family: | Ulmaridae |
Genus: | Aurelia Lamarck, 1816 |
Species | |
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Aurelia is a genus of jellyfish that are commonly called moon jellies, which are in the class Scyphozoa. There are currently 25 accepted species and many that are still not formally described. [1] [2] [3]
The genus was first described in 1816 by Jean-Baptiste Lamarck in his book Histoire Naturelle des Animaux sans Vertèbres (Natural History of Invertebrates). [4] It has been suggested that Aurelia is the best-studied group of gelatinous zooplankton, with Aurelia aurita the best-studied species in the genus; two other species, Aurelia labiata and Aurelia limbata were also traditionally investigated throughout the 20th century. [5] In the early 2000s, studies that considered genetic data showed that diversity in Aurelia was higher than expected based solely on morphology, [6] [7] so one cannot confidently attribute the results from most of the previous studies to the species named. More recently, studies have highlighted the morphological variability [2] (including the potential for phenotypic plasticity [8] [9] ) in this genus, emphasizing the difficulty of identifying cryptic species. [10]
Species of Aurelia can be found in the Atlantic, Arctic, Pacific and Indian Oceans, and seem to be more common in temperate regions, such as in the waters off northern China, Japan, Korea, New Zealand, the northeastern and northwestern coasts of the United States, and those of northern Europe. [2]
Aurelia undergoes alternation of generations, whereby the sexually-reproducing pelagic medusa stage is either male or female, and the benthic polyp stage reproduces asexually. Meanwhile, life cycle reversal, in which polyps are formed directly from juvenile and sexually mature medusae or their fragments, was also observed in Aurelia coerulea (= Aurelia sp. 1). [11]
The similar appearances of moon jellyfish is what has made them so hard to identify. They tend to have a variety of different sizes, however, they typically range from 5–38 cm (2.0–15.0 in) in diameter with an average of 18 cm (7.1 in) wide and 8 cm (3.1 in) in height. [12] The polyps of these jellyfish can grow to 1.6 cm (0.63 in) tall and their ephyrae have an average diameter of 0.4 cm (0.16 in). [13] The adult medusae are typically translucent in color [13] but the color of their gut can change based on what they eat; for example, if they eat crustaceans, they can have a pink or lavender tint to them and if they were to eat brine shrimp, the tint would be more of an orange color. [14] Their polyps usually have around 16 tentacles (although Aurelia insularia has 27-33 tentacles) [2] [15] which mostly help with feeding. [13]
The diet of Aurelia is similar to that of other jellyfish. They primarily feed on zooplankton. [12] They may prey on or compete with commercially important fish and their larvae, as well as cause several issues for trawling boats when large aggregations occur, [16] as they may clog and damage fishing nets as well as force fisherman to relocate. [17]
They are able to sense light and dark and up and down due to rhopalia around the bell margin. [12] After many tests on frogs, it was determined that A. aurita has a proteinaceous venom that causes muscle twitching by inducing the irreversible depolarization of the muscle membrane that is believed to be caused by an increase in the membrane's permeability to sodium ions. [18]
The medusa stage of the jellyfish reproduce sexually. The males release strings of sperm and the females ingest them. [14] Once the ciliated larvae develop from the egg, they settle on or near the sea floor and develop into benthic polyps. The polyps then reproduce asexually and bud into ephyrae which later turn into medusae.
The Scyphozoa are an exclusively marine class of the phylum Cnidaria, referred to as the true jellyfish.
Aurelia aurita is a species of the family Ulmaridae. All species in the genus are very similar, and it is difficult to identify Aurelia medusae without genetic sampling; most of what follows applies equally to all species of the genus.
Medusozoa is a clade in the phylum Cnidaria, and is often considered a subphylum. It includes the classes Hydrozoa, Scyphozoa, Staurozoa and Cubozoa, and possibly the parasitic Polypodiozoa. Medusozoans are distinguished by having a medusa stage in their often complex life cycle, a medusa typically being an umbrella-shaped body with stinging tentacles around the edge. With the exception of some Hydrozoa, all are called jellyfish in their free-swimming medusa phase.
Phacellophora camtschatica, commonly known as the fried egg jellyfish or egg-yolk jellyfish, is a very large jellyfish in the family Phacellophoridae. This species can be easily identified by the yellow coloration in the center of its body which closely resembles an egg yolk, hence how it got its common name. Some individuals can have a bell close to 60 cm (2 ft) in diameter, and most individuals have 16 clusters of up to a few dozen tentacles, each up to 6 m (20 ft) long. A smaller jellyfish, Cotylorhiza tuberculata, typically found in warmer water, particularly in the Mediterranean Sea, is also popularly called a fried egg jellyfish. Also, P. camtschatica is sometimes confused with the Lion's mane jellyfish.
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".
Nausithoe aurea, also known as the Nausithoe maculata, is a species of crown jellyfish found off the southeastern coast of Brazil. The central disc has been measured to be 10.5 mm. N. aurea is transparent with yellow and brown spots located around the gonads. N. aurea can reproduce either asexually by strobilation or sexually. Either ephyrae or planuloids may be produced by strobilation; only ephyrae can produce the medusal form. Strobilation can be induced to occur when food is abundant. In polyps, a large availability of food leads to strobilation if it is not regulated. N. aurea species usually take more than 20 weeks to begin the differentiation and development of reproductive organs.
Cyanea is a genus of jellyfish, primarily found in northern waters of the Atlantic and Pacific Oceans and southern Pacific waters of Australia and New Zealand, there are also several boreal, polar, tropical and sub-tropical species. Commonly found in and associated with rivers and fjords. The same genus name has been given to a genus of plants of the Hawaiian lobelioids, an example of a parahomonym.
Aurelia labiata is a species of moon jellyfish. It is a cnidarian in the family Ulmaridae. It is typically larger than Aurelia aurita, with individuals document up to 45 cm (18 in). However, much of its size range overlaps with A. aurita, making size an imperfect diagnostic tool. Most Aurelia labiata have a 16-scalloped bell, meaning the bell indents inward at 16 points, a characteristic that also appears in other Aurelia species. Aurelia labiata occurs in the northeastern Pacific Ocean, from the northern coast of California, north to Canada and into Alaska.
Sanderia malayensis is a species of jellyfish in the family Pelagiidae, native to the tropical Indo-Pacific. It has a complex life cycle and is thought to be venomous and to have caused injuries to humans.
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).
Aurelia coerulea or Asian moon jelly is a species of moon jelly in the genus Aurelia. This species is native to the seas off Japan, China, Korea, and California, as well as the Mediterranean and other temperate seas. and they can also be found in coastal areas of China, Korea, California, the Mediterranean and other temperate seas. It is particularly abundant in artificial habitats and sheltered regions. It has a very high reproductive rate which can cause blooming events. A.coerulea blooming causes problems such as impairing fisheries, clogging the nuclear power plants and disrupting the local zooplankton abundance. The chemical compounds the species secretes as a self-defense mechanism can be used for pharmaceutical purposes.
Aurelia limbata, the brown-banded moon jelly, is a type of moon jelly that occurs in various places throughout the Pacific Ocean.
Aurelia marginalis is a species of the genus Aurelia. All species in the genus are very similar, and it is difficult to identify Aurelia medusae without genetic sampling.
Aurelia cebimarensis is a species of true jellyfish in the family Ulmaridae. It is known via type specimens found in waters off the coast of Brazil.
Aurelia columbia is a species of true jellyfish in the family Ulmaridae. It is known via type specimens found in waters off the coasts of the Northwestern United States and British Columbia.
Aurelia insularia is a species of true jellyfish in the family Ulmaridae. It is known via polyp type specimens found in waters off the coast of Brazil, around Ilha Grande.
Aurelia malayensis is a species of true jellyfish in the family Ulmaridae. It is known via type specimens found in the Philippines.
Aurelia miyakei is a species of true jellyfish in the family Ulmaridae. It is found in the Gulf of Thailand and the Kwajalein Atoll.
Aurelia montyi is a species of true jellyfish in the family Ulmaridae. It is found in the eastern Gulf of Mexico.
Aurelia rara is a species of true jellyfish in the family Ulmaridae. It is known from type specimens found near Dauphin Island.