| Leucothea | |
|---|---|
 | |
| Leucothea pulchra at the Monterey Bay Aquarium | |
Scientific classification  | |
| Domain: | Eukaryota |
| Kingdom: | Animalia |
| Phylum: | Ctenophora |
| Class: | Tentaculata |
| Order: | Lobata |
| Family: | Leucotheidae Krumbach, 1925 |
| Genus: | Leucothea Mertens, 1833 |
| Species | |
See text | |
Leucothea is a genus of ctenophores in the monotypic family Leucotheidae. [1]
The genus contains the following species: [2]
Like other species in the order Lobata, Leucothea species have a distinct, compressed body shape with two prominent lobes on either side, these being their most distinguishing features. In addition to these two large lobes, they have 4 lengthy, coiled auricles lined with cilia extending around the mouth which assist the animal in guiding prey into the mouth; [10] these auricles will uncoil at points and wave, potentially working to lure prey. There are two tentacles on either side originating around the oral pole [10] Leucothea can be identified by their oblong bodies which have fairly long lobes, taking up almost half of their length [11] with papillae across the body and lobes. [10] They are around 13-20cm, completely transparent, but bioluminescent and have gelatinous spikes that are thought to serve a sensory purpose as they are found to point towards stimuli. [11] Out of their eight ctene rows, four are sub-stomodaeal and stop towards the aboral pole while the others are sub-tentacular and extend to the auricles. [12]
They are easily mistaken for Bolinopsis sp.. [11] Bolinopsis' lobes are attached at the end of their bodies, making them appear very similar to Leucothea – the main difference in the two when trying to identify being the sensory spikes possessed by the latter. [11] Leucothea is thought to have ties to Bolinopsis through similar ancestors which make them very difficult to distinguish at times, especially during Leucothea's 'Bolinopsis phase' in growth when it has not yet grown its surface papillae and the two can hardly be told apart. [10]
Leucothea are able to reproduce through self-fertilization and will release hundreds of offspring at a time. Development of these organisms varies by species – for example, through its larval life phase, Leucothea multicornis (of the Mediterranean) passes through a Cydippe-like stage, then a medusiform stage, and then onto the Bolinopsis stage before reaching its Leucothea stage in contrast with Leucothea ochracea (North American) which has prominent yellow markings on the lobes and filaments which the Mediterranean species lack, implying that their development would have to be different although it is not specifically stated how. [10]
By use of their ctene rows, Leucothea travel through the water just like any other ctenophore, they will adjust their direction of travel once they sense a stimulus of some kind – like prey. They are able to travel vertically at higher speeds by using jet propulsion; they will travel much slower when moving horizontally. [13] In times when they do not need to move, they cease use of their ciliary rows and just drift through the water. [14] Leucothea is different in its foraging habits than other Ctenophores because it glides through the water with its lobes spread wide – the lobes are lined with colloblasts which will allow prey to adhere to its surface, the auricles and tentacles will wave as well in order to catch other organisms. [15] When moving horizontally, the oral lobes open and spread out, some compare it to flying and the auricles move in a way to help funnel in food; [13] they are thought to only move horizontally during feeding. Leucothea will move to any area in the water column where their prey is the most abundant, in the case of a study carried out on Leucothea in California, 45% of the organisms were found collected between 18-22m feeding on various copepods that thrive at that depth. It is thought that they mainly feed horizontally since their prey seem to aggregate in layers at certain depths, it would not be optimal for Leucothea to travel upwards or downwards through the layer when they could travel through it and potentially have access to more food. They will travel extremely slowly during this period so as not to disturb the water and expose their presence while trying to forage. Their digestive tracts were found to have mainly copepods and snails, raising the idea that they may eat specific organisms, rather than everything. [14]
Lobata is an order of transparent marine invertebrates belonging to the phylum of Ctenophora in the class Tentaculata, and are commonly referred to as comb jellies or sea gooseberries. There are currently 19 extant known species in the order of Lobata. Members of Lobata exhibit a compressed body in the vertical plane and a pair of oral lobes. They are known to inhabit marine pelagic surfaces and the marine shores.
Bathocyroe fosteri is a species of lobate ctenophore found at intermediate depths in all the world's oceans. The species is very common and abundant near the Mid-Atlantic Ridge. It is bioluminescent, and is typically observed hanging motionlessly in an upright or inverted posture although it can flap its oral lobes to swim. This deep-sea comb jelly is named for Alvin (DSV-2) pilot Dudley Foster, who collected the first specimens.
Heteroconchia is a taxonomic infraclass of diverse bivalve molluscs, belonging to the subclass Autobranchia.
Chrysaora colorata (Russell), commonly known as the purple-striped jelly or purple-striped sea nettle, 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.
Ocyropsis is a genus of Ctenophores, which are commonly known as Comb Jellies. Ocyropsis belong to the family of Ocyropsidae. Ocyropsis possesses two large lateral muscular lobes and four auricles, and appear pale and translucent in color. Ocyropsis habitat is not precise as their gelatinous composition can make it difficult to study. They have been found in warm and cold waters. Unlike other, slow swimming Ctenophores, Ocyropsis are efficient in evading their predators. They use their oral lobes for additional propulsion and a secrete luminous mucous in efforts to evade predators. The muscular oral lobes of the Ocyropsis are used to grab its prey, and then moved to the prehensile mouth for absorption.
The World Register of Marine Species (WoRMS) is a taxonomic database that aims to provide an authoritative and comprehensive list of names of marine organisms.
Bolinopsidae is a family of ctenophores.
Eurhamphaeidae is a family of ctenophores.
Haliclystidae is a family of stalked jellyfish in the order Stauromedusae.
The Venus girdle is a comb jelly in the family Cestidae. It is the only member of its genus, Cestum, and is also the largest of all known ctenophores.
Beroe, commonly known as the cigar comb jellies, is a genus of comb jellies in the family Beroidae. Beroe exhibits bioluminescence.
Bolinopsis infundibulum, commonly known as the common northern comb jelly, is a species of comb jelly in the family Bolinopsidae. It is found in the northern Atlantic Ocean and was first described by the Danish naturalist Otto Friedrich Müller in 1776.
Pleurobrachia pileus is a species of comb jelly, commonly known as a sea gooseberry. It is found in open water in the northern Atlantic Ocean, the North Sea, the Baltic Sea and the Black Sea, and was first described by the Danish zoologist Otto Friedrich Müller in 1776.
Thalassocalyce is a genus of ctenophore, or comb jellies, known from the California Coast, Gulf of Mexico, and west north Atlantic. It is represented by a single species, Thalassocalyce inconstans, which is the only species in the family Thalassocalycidae and the order Thalassocalycida. T. inconstans is a pelagic ctenophore typically occurring in upper-mesopelagic depths, but has been observed at depths up to 3,500 m in Monterey Canyon.
Borsonia ochracea is a species of sea snail, a marine gastropod mollusk in the family Borsoniidae.
Euplokamis is a genus of ctenophores, or comb jellies, belonging to the monotypic family Euplokamididae. It shares the common name sea gooseberry with species of the genus Pleurobrachia. Despite living for hundreds of millions of years in marine environments, there is minimal research regarding Euplokamis, because they are uncommon. Research on the evolution of the basic body structures of diploblastic metazoans revealed that there are four major phyla, including the Ctenophores. Although the morphology of Euplokamis often resembles the medusa stage of Cnidarians, their eight rows of combs are one distinguishing feature that led to the official classification of Ctenophores. After being originally described by Chun (1879), the family Euplokamididae was expanded by Mills (1987) due to the discovery of a new species, Euplokamis dunlapae. Further research indicated that Euplokamis should be identified from Mertensiidae due to the rows of combs and some compression. They may also be distinguished from the genus Pleurobrachia due to their more elongated shape. Additionally, various adaptations of Euplokamis have been observed such as the use of tentacles for movement/feeding, a complex nervous system, and bioluminescent capabilities. Other characteristics including a defined mesoderm, lack of stinging cells, developmental differences, and symmetry supported the reclassification of these organisms.
Platyctenidae is a family of ctenophores belonging to the order Platyctenida.
Bolinopsis mikado is a species of ctenophore in the family Bolinopsidae. It is found in the waters of Japan.
Euplokamis helicoides is a species of marine ctenophore. It has been reported to be a fast swimmer.
Euplokamis evansae is a marine species of ctenophore.
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