| Elpidia minutissima | |
|---|---|
Scientific classification  | |
| Kingdom: | Animalia |
| Phylum: | Echinodermata |
| Class: | Holothuroidea |
| Order: | Elasipodida |
| Family: | Elpidiidae |
| Genus: | Elpidia |
| Species: | E. minutissima |
| Binomial name | |
| Elpidia minutissima Belyaev, 1971 [1] | |
Elpidia minutissima is a species of deep-sea swimming sea cucumber in the family Elpidiidae. It is a detritivore and is found in the northern Pacific Ocean.
Specimens collected from the Aleutian Trench averaged 13 mm (0.5 in) in length and had three pairs of dorsal podia whereas specimens collected from Station M in the northeastern Pacific Ocean at a depth of about 4,000 metres (13,000 ft) had four pairs, two pairs on the dorsal surface and two pairs on the ventral surface, the hindermost of the ventral podia being shorter than the others. At times of low abundance, the average length of these sea cucumbers was similar to the specimens from the Aleutian Trench but at times of high abundance it increased to 25 mm (1.0 in). It is possible that these two populations are not in fact the same species. [2]
Elpidia minutissima feeds on detritus on the seabed, the result of "marine snow" consisting of mucus, faeces and organic debris, that sink into the depths from surface waters. [2] It plays an important part in the processing, utilization and redistribution of particles of organic material that has fallen to the sea bed. [3]
Elpidia minutissima is one of a number of echinoderm species that show great variations in population density. Researchers in one study found that, over a sixteen-year period, two deep sea holothurians, E. minutissima and Peniagone vitrea , underwent a decline in density of the order of one to two magnitudes. It has been hypothesized that two factors that increase the likelihood of large swings in population are broadcast spawning and the possession of planktotrophic larvae. These factors provide a positive feedback loop so that once populations decline, recovery is very slow. When individual organisms are further apart, broadcast spawning is less likely to result in fertilisation and this means fewer larvae available for recruitment. [4]
An echinoderm is any member of the phylum Echinodermata of marine animals. The adults are recognizable by their radial symmetry, and include starfish, sea urchins, sand dollars, and sea cucumbers, as well as the sea lilies or "stone lilies". Adult echinoderms are found on the sea bed at every ocean depth, from the intertidal zone to the abyssal zone. The phylum contains about 7000 living species, making it the second-largest grouping of deuterostomes, after the chordates. Echinoderms are the largest phylum that has no freshwater or terrestrial members.
Sea cucumbers are echinoderms from the class Holothuroidea. They are marine animals with a leathery skin and an elongated body containing a single, branched gonad. Sea cucumbers are found on the sea floor worldwide. The number of holothurian species worldwide is about 1,717 with the greatest number being in the Asia Pacific region. Many of these are gathered for human consumption and some species are cultivated in aquaculture systems. The harvested product is variously referred to as trepang, namako, bêche-de-mer or balate. Sea cucumbers serve a useful role in the marine ecosystem as they help recycle nutrients, breaking down detritus and other organic matter after which bacteria can continue the degradation process.
Scotoplanes is a genus of deep-sea sea cucumbers of the family Elpidiidae. Its species are commonly known as sea pigs.
Isostichopus fuscus, commonly known as the brown sea cucumber, is a species of sea cucumber in the family Stichopodidae native to the eastern Pacific. It was first described to science by German biologist Hubert Ludwig in 1875.
Holothuria mexicana, the donkey dung sea cucumber, is commonly found in the Caribbean and the Azores. It is a commercially important aspidochirote sea cucumber that can reach a total length of 50 cm (20 in).
Psychropotes longicauda is a species of sea cucumber in the family Psychropotidae. It inhabits the deep sea where the adult is found on the seabed. The larva is pelagic and has an appendage shaped like a sail on its back which may enable it to move through the water.
Holothuria scabra, or the sandfish, is a species of sea cucumber in the family Holothuriidae. It was placed in the subgenus Metriatyla by Rowe in 1969 and is the type species of the subgenus. Sandfish are harvested and processed into "beche-de-mer" and eaten in China and other Pacific coastal communities.
Amperima rosea is a species of sea cucumber in the family Elpidiidae. It is found on the seabed at abyssal depths of 4,000 m (2.5 mi) or more. Around 1996, its numbers in the Porcupine Abyssal Plain in the northeastern Atlantic increased dramatically from a few individuals per hectare to over six thousand per hectare, a phenomenon that became known as the "Amperima event".
Pelagothuria is a genus of sea cucumbers in the family Pelagothuriidae. It is monotypic, being represented by the single species Pelagothuria natatrix.
Elpidiidae is a family of deep-sea sea cucumbers.
Elpidia is a genus of deep-sea sea cucumbers. Members are characterised by their rod-shaped spicules which each have two pairs of obliquely-placed horizontal arms and two vertical apophyses. There is a high degree of endemism in this genus with different species occupying different deep sea basins or regions.
Peniagone vitrea is a species of deep-sea swimming sea cucumber in the family Elpidiidae. It is a detritivore and is found in the northern Pacific Ocean at abyssal depths. It was first described by the Swedish zoologist Hjalmar Théel in 1879, being one of the many deep sea animals discovered during the Challenger expedition of 1872–1876.
Elpidia glacialis is a species of sea cucumber in the family Elpidiidae. It is found at abyssal depths in the Arctic Ocean, the Barents Sea, the Kara Sea and the north Atlantic Ocean. It was first described in 1876 by the Swedish zoologist Johan Hjalmar Théel after he had collected specimens while accompanying the explorer Adolf Erik Nordenskiöld on an expedition attempting to find the Northeast Passage.
Scotoplanes globosa, commonly known as the sea pig, is a species of sea cucumber that lives in the deep sea. It was first described by Hjalmar Théel, a Swedish scientist. Scotoplanes globosa, along with numerous other sea cucumbers were discovered by Théel during an expedition on HMS Challenger between the years of 1873-1876. Scotoplanes globosa was officially described in 1882, 6 to 9 years after its first sighting. Scotoplanes globosa is most closely related to the genus Peniagone.
Thelenota rubralineata is a species of sea cucumber in the family Stichopodidae, in the phylum Echinodermata, mainly located in the central Indo-Pacific region. It has a distinctive coloring pattern, and can be found on the seabed near coral. T. rubralineata is part of the Thelenota genus, characterized by their large size and the presence of a calcareous ring.
Leptopentacta elongata is a species of sea cucumber in the family Cucumariidae. It is found in the northeastern Atlantic Ocean and parts of the Mediterranean Sea. It is an infaunal species, occupying a burrow in the seabed, from which its anterior and posterior ends project.
Cucumaria vegae, also known as tiny black sea cucumber or northern tar spot, is a species of sea cucumber. It was first described to science by Johan Hjalmar Théel in 1886 reporting on the sea cucumber specimens brought back by the Challenger expedition. Among these was the type specimen for this species, which was collected at Bering Island.
Holothuria grisea, the gray sea cucumber, is a mid-sized coastal species of sea cucumber found in shallow tropical waters of the Atlantic Ocean from Florida to Southern Brazil and West Africa. They have a variety in color and can range from red to more yellowish with brown markings. They are also a food source for local and international markets with the majority of harvesting taking place in Brazil. This species is currently not over-fished and is not endangered or threatened.
Psychropotidae is a family of deep-sea swimming sea cucumbers. The geographic range of some psychropotids is very extensive at abyssal depths, whereas other species are found within more restricted ranges.
Benthodytes is a genus of sea cucumbers in the family Psychropotidae.
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