| Edwardsiella lineata | |
|---|---|
 | |
Scientific classification  | |
| Kingdom: | Animalia |
| Phylum: | Cnidaria |
| Class: | Hexacorallia |
| Order: | Actiniaria |
| Family: | Edwardsiidae |
| Genus: | Edwardsiella |
| Species: | E. lineata |
| Binomial name | |
| Edwardsiella lineata | |
| Synonyms [2] | |
| |
Edwardsiella lineata, the lined anemone, is a species of sea anemone in the family Edwardsiidae. It is native to the northwestern Atlantic Ocean where it occurs in the subtidal zone.
E. lineata is a small, delicate-looking, white or brownish anemone with a typical length of 15-20 millimeters as an adult polyp. It has a simple body plan, possessing only 8 complete mesenteries, and 18-24 tentacles. The body of an adult is composed of four distinct regions defined by tissue type: the oral disc containing the tentacles, the capitulum which houses the actinopharynx or "gut", the scapus, and the aboral end. It is capable of lengthening and shortening its body using retractor and parietal muscles present on these mesenteries. [3] It possesses various types of cnidae, including acontia (threadlike defensive organs thrown out of the mouth or special pores when irritated). It lives in a slender mucous tube immersed in sediment. [4]
E. lineata is native to shallow temperate waters in the northwestern Atlantic Ocean, where it occurs between Cape Cod and Cape Hatteras. [2] It is typically found in rock crevices and on and under rocks in the sublittoral zone at depths to 20 m (66 ft), but can also be infaunal, burrowing in soft sediment. It sometimes occurs in large numbers. [5] [6] There have been reports of possible E. lineata in the Northeast Atlantic, though the organisms could only be confirmed down to the genus level. [7] E. lineata is genetically almost indistinguishable from its close relative E. carnea, which is native to the Northeast Atlantic and whose life cycle is currently unknown. [8]
E. lineata has a simple internal structure and is unusual among sea anemones in that it can divide by transverse fission. [5] This type of asexual reproduction can be achieved through either physal pinching or polarity reversal. In physal pinching, a constriction occurs at the aboral (physal) end of the anemone and the fragment then "pinches" off, at which point the fragment regenerates to form a fully functional adult polyp. During polarity reversal, oral structures form at the aboral end of the anemone resulting in an animal with two oral ends. Physal tissue then forms at the midpoint of the oral ends and a constriction separates the two anemones. [3] It can also reproduce sexually through broadcast spawning and the resulting planula larva has recently evolved a partially parasitic lifestyle [ citation needed ]
The planula larvae are sometimes the cause of a form of irritating dermatitis in humans known as seabather's eruption. [9] When the larvae get trapped under swimwear they defend themselves by firing their venomous nematocysts into the skin, causing a red blotchy rash that may blister. No treatment is required, and the symptoms subside after a week or two. [10] [11]
E. lineata is the only known member of the Edwardsiidae family to have a parasitic life stage. [3] Upon fertilization, a primary planula develops. Instead of direct development into an adult polyp like many other anemone species such as its close relative Nematostella vectensis , [12] it infects a species of pelagic ctenophore known as Mnemiopsis leidyi . The planula can infect its host in two ways: burrowing through epidermal walls or burrowing through gastrodermal walls into the gut after being eaten by an M. leidyi. [3] It is common for a single M. leidyi to harbor multiple E. lineata parasites. [13] On entering a host, the larva adopts a worm-like appearance and feeds on the contents of the host's gut. When sufficiently developed, or if the host dies, it exits the host and regains its planula larval form. If another host is available it can once again adopt the worm-like phase, but if no new host is available, it can settle on the seabed and undergo metamorphosis into a juvenile sea anemone polyp. [14] This metamorphosis can take as little as three days. If the parasitic larva is artificially excised from its host it may also undergo metamorphosis into a polyp, [3] presumably because manual excision mimics natural death of the host or the parasite voluntarily leaving. E. lineata has been proposed as a possible biological control on the voracious planktivore M. leidyi, though this has yet to be artificially implemented. Infected ctenophores have lower growth rates than their non-infected counterparts, sometimes even negative growth rates, or "shrinking", leading to thoughts that E. lineata could help depress the population of M. leidyi in areas where it becomes damaging to fisheries. [7]
In addition to being found inside M. leidyi, E. lineata has been found inside another species of ctenophore known as Beroe ovata. However, evidence suggests that this is the result of a secondary infection and that B. ovata is not the first or intended host. B. ovata are known to prey on M. leidyi, and it is presumed that when a B. ovata consumes an infected M. leidyi, that the E. lineata parasites then embed themselves in the tissue of the B. ovata. This is evidenced by the fact that E. lineata parasites are often found in the radial canals of B. ovata, rather than the gut area like in M. leidyi, suggesting that the E. lineata aren't using the B. ovata to feed but rather ended up there through predation. [13]
Cnidaria is a phylum under kingdom Animalia containing over 11,000 species of aquatic animals found both in freshwater and marine environments, predominantly the latter.
Ctenophora comprise a phylum of marine invertebrates, commonly known as comb jellies, that inhabit sea waters worldwide. They are notable for the groups of cilia they use for swimming, and they are the largest animals to swim with the help of cilia.
Anthozoa is a class of marine invertebrates which includes the sea anemones, stony corals and soft corals. Adult anthozoans are almost all attached to the seabed, while their larvae can disperse as part of the plankton. The basic unit of the adult is the polyp; this consists of a cylindrical column topped by a disc with a central mouth surrounded by tentacles. Sea anemones are mostly solitary, but the majority of corals are colonial, being formed by the budding of new polyps from an original, founding individual. Colonies are strengthened by calcium carbonate and other materials and take various massive, plate-like, bushy or leafy forms.
Beroidae is a family of ctenophores or comb jellies more commonly referred to as the beroids. It is the only family within the monotypic order Beroida and the class Nuda. They are distinguished from other comb jellies by the complete absence of tentacles, in both juvenile and adult stages. Species of the family Beroidae are found in all the world's oceans and seas and are free-swimmers that form part of the plankton.
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.
Mnemiopsis leidyi, the warty comb jelly or sea walnut, is a species of tentaculate ctenophore. It is native to western Atlantic coastal waters, but has become established as an invasive species in European and western Asian regions. Three species have been named in the genus Mnemiopsis, but they are now believed to be different ecological forms of a single species M. leidyi by most zoologists.
The starlet sea anemone is a species of small sea anemone in the family Edwardsiidae native to the east coast of the United States, with introduced populations along the coast of southeast England and the west coast of the United States. Populations have also been located in Nova Scotia, Canada. This sea anemone is found in the shallow brackish water of coastal lagoons and salt marshes where its slender column is usually buried in the mud and its tentacles exposed. Its genome has been sequenced and it is cultivated in the laboratory as a model organism, but the IUCN has listed it as being a "Vulnerable species" in the wild.
Crithidia fasciculata is a species of parasitic excavates. C. fasciculata, like other species of Crithidia have a single host life cycle with insect host, in the case of C. fasciculata this is the mosquito. C. fasciculata have low host species specificity and can infect many species of mosquito.
Aiptasia is a genus of a symbiotic cnidarian belonging to the class Anthozoa. Aiptasia is a widely distributed genus of temperate and tropical sea anemones of benthic lifestyle typically found living on mangrove roots and hard substrates. These anemones, as well as many other cnidarian species, often contain symbiotic dinoflagellate unicellular algae of the genus Symbiodinium living inside nutritive cells. The symbionts provide food mainly in the form of lipids and sugars produced from photosynthesis to the host while the hosts provides inorganic nutrients and a constant and protective environment to the algae. Species of Aiptasia are relatively weedy anemones able to withstand a relatively wide range of salinities and other water quality conditions. In the case of A. pallida and A. pulchella, their hardiness coupled with their ability to reproduce very quickly and out-compete other species in culture gives these anemones the status of pest from the perspective of coral reef aquarium hobbyists. These very characteristics make them easy to grow in the laboratory and thus they are extensively used as model organisms for scientific study. In this respect, Aiptasia have contributed a significant amount of knowledge regarding cnidarian biology, especially human understanding of cnidarian-algal symbioses, a biological phenomenon crucial to the survival of corals and coral reef ecosystems. The dependence of coral reefs on the health of the symbiosis is dramatically illustrated by the devastating effects experienced by corals due to the loss of algal symbionts in response to environmental stress, a phenomenon known as coral bleaching.
Sea anemones are a group of predatory marine invertebrates of 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.
Peachia quinquecapitata, also known as the twelve-tentacled parasitic anemone, is a species of sea anemone in the family Haloclavidae. It is found in the Pacific Northwest. The larva is parasitic on certain species of Anthomedusae.
Beroe ovata is a comb jelly in the family Beroidae. It is found in the South Atlantic Ocean and the Mediterranean Sea and has been introduced into the Black Sea, the Aegean Sea, the Sea of Azov and the Caspian Sea. It was first described by the French physician and zoologist Jean Guillaume Bruguière in 1789.
Beroe cucumis is a species of comb jelly in the family Beroidae. It is found in the Atlantic Ocean. It was first described by the Danish missionary and naturalist Otto Fabricius in 1780.
Nematosomes are multicellular motile bodies found in the gastrovascular cavity of the model sea anemone Nematostella vectensis starlet sea anemone. First described by Stephenson in 1935, nematosomes are the defining apomorphy (synapomorphy) of the genus Nematostella but have received relatively little study. Nematosomes can be observed circulating through the body cavity and tentacle lumen of adult anemones, occasionally coming to rest on the gastrodermis. Nematosomes that are dislodged from rest return to circulation. The lifespan of a single nematosome has not been studied.
Diadumene leucolena, commonly known as the white anemone or ghost anemone, is a species of sea anemone in the family Diadumenidae. It is an inconspicuous species found in the intertidal and subtidal areas of the northeastern Atlantic Ocean, the Caribbean Sea and the northern Pacific Ocean. Diadumene, "diadem-bearer", referring to the crown of tentacles, is a female form intended to bring to mind the Diadumenos, the renowned Greek sculpture of an athlete crowning himself with the victor's ribbon diadem.
Thyonicola americana is a species of parasitic sea snail, a marine gastropod mollusc in the family Eulimidae. It infests the sea cucumbers Eupentacta quinquesemita and Eupentacta pseudoquinquesemita in Puget Sound and other parts of the northeastern Pacific Ocean.
Clistosaccus is a genus of barnacles which are parasitic on hermit crabs. It is a monotypic genus, and the single species is Clistosaccus paguri, which is found in the northern Atlantic Ocean and the northern Pacific Ocean.
Clytia hemisphaerica is a small hydrozoan-group cnidarian, about 1 cm in diameter, that is found in the Mediterranean Sea and the North-East Atlantic Ocean. Clytia has the free-swimming jellyfish form typical of the Hydrozoa, as well as vegetatively propagating polyps.
Clava is a monotypic genus of hydrozoans in the family Hydractiniidae. It contains only one accepted species, Clava multicornis. Other names synonymous with Clava multicornis include Clava cornea, Clava diffusa, Clava leptostyla, Clava nodosa, Clava parasitica, Clava squamata, Coryne squamata, Hydra multicornis, and Hydra squamata. The larvae form of the species has a well developed nervous system compared to its small size. The adult form is also advanced due to its ability to stay dormant during unfavorable periods.
Beroe gracilis is a species of comb jelly in the family Beroidae. It is a free-swimming species found in the North Sea, the Atlantic Ocean and the Mediterranean Sea.
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