Holothuria leucospilota known as the black sea cucumber/ Black tarzan, is a species of marine invertebrate in the family Holothuriidae. It has been placed in the subgenus Mertensiothuria making its full scientific name Holothuria leucospilota, it is the type species of the subgenus and is found on the seabed in shallow water in the Indo-Pacific. Holothuria leucospilota is a medium-sized sea cucumber reaching a length of up to 40 centimetres when relaxed but it can stretch to about a metre when extended, it is cylindrical, tapering towards the posterior end. At the anterior end, there are twenty oral tentacles with branched tips; these surround the mouth, on the under side of the body. The animal is covered with fleshy papillae; the usual colour is charcoal grey or reddish-black with pale grey tube feet on the underside but off the African coast it is described as being bright or dark brown with white patches which are larger towards the posterior end. Holothuria leucospilota is found in shallow water along the east coast of Africa and in much of the Indo-Pacific region.
It is a common species on the north east coast of Australia where it is found on reefs and rocky coasts partly concealed under a boulder. A study done near Singapore found that Holothuria leucospilota was more common near boulders and seaweed clumps than it was on the open seabed, it found that this species is tolerant of changes in salinity and temperature and continued to thrive in the laboratory when these parameters were changed. Under the same conditions, the Japanese sea cucumber shrank in size and died within three days. In Singapore, Apostichopus japonicus is consumed as food and is becoming rare as a result of overexploitation. Holothuria leucospilota is a scavenger and when feeding it has its posterior end anchored underneath a rock or in a crevice so that it can contract back out of sight if disturbed, it feeds by using its tentacles to shovel organic debris lying on the seabed into its mouth. In the process it swallows a significant quantity of sand. If threatened, Holothuria leucospilota can emit a mass of fine sticky Cuvierian tubules from its anus which ensnare the potential predator allowing the sea cucumber to escape.
It can regenerate these tubules in fifteen to eighteen days. The worm pearlfish is a parasite of this species and each parasitised H. leucospilota will host a male and female pair of the fish which live inside its body
Holothuria atra known as the black sea cucumber or lollyfish, is a species of marine invertebrate in the family Holothuriidae. It was placed in the subgenus Halodeima by Pearson in 1914, making its full scientific name Holothuria atra, it is the type species of the subgenus. Holothuria atra is a sea cucumber that can grow to a length of 60 centimetres but 20 centimetres is a more common size, it has a smooth, pliable black skin which has sand adhering to it in smaller individuals. The mouth is on the underside at one end and is surrounded by a fringe of 20, branched tentacles; the anus is at the other end. Holothuria atra is found in the tropical Indo-Pacific region, its range extending from the Red Sea and East Africa to Australia, it is found on the seabed, in shallow waters on reefs and sand flats and in seagrass meadows at depths of up to 20 metres. Its colouring makes it conspicuous but it is often camouflaged by a coating of sand which may serve to keep it cool by protecting it from the sun's rays.
It favours reef flats where it is not exposed to the waves but the water is well aerated, shallows beside slabs of rock from under which cool water wells out when the tide retreats. In such places it is found in pools above the low tide mark which are warmed by the sun during the day. Holothuria atra seems to tolerate these high temperatures well and individuals appeared healthy and were feeding when the water temperature rose as high as 39 °C. Holothuria atra is an omnivore, sifting through the sediment with its tentacles and feeding on detritus and other organic matter; as a defence against predators, Holothuria atra emits a toxic red fluid when its skin is rubbed or damaged. When attacked, it does not eject Cuvierian tubules in the way that some sea cucumbers do, but instead extrudes its internal organs through its anus, it is not possible to distinguish between male and female Holothuria atra externally. Maturity is reached at a body length of about 16 centimetres and spawning takes place during the summer and autumn although in equatorial waters it may take place all year round.
Holothuria atra is fissiparous, meaning that it can reproduce by transverse fission. It is smaller individuals that divide in this way. A constriction appears, becomes deeper and deeper and after some time the integument separates leaving two wide but short individuals. No sand adheres to the newly separated surfaces as there are no tube feet present to retain the grains. Holothuria atra is found associated with the polychaete worm Gastrolepidia clavigera, a black worm which crawls about over the sea cucumber's skin. Holothuria atra seems to have few natural predators. Lissocarcinus orbicularis, a small crab, is known to live on this species in a commensal relationship. In the Pacific Islands, Holothuria atra is collected by diving or by wading at low tide, used for human consumption.
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 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. Like all echinoderms, sea cucumbers have an endoskeleton just below the skin, calcified structures that are reduced to isolated microscopic ossicles joined by connective tissue. In some species these can sometimes be enlarged to flattened plates. In pelagic species such as Pelagothuria natatrix, the skeleton is absent and there is no calcareous ring.
The sea cucumbers are named after their resemblance to the fruit of the cucumber plant. Most sea cucumbers, as their name suggests, have a soft and cylindrical body, more or less lengthened, rounded off and fat in the extremities, without solid appendages, their shape ranges from spherical for "sea apples" to serpent-like for Apodida or the classic sausage-shape, while others resemble caterpillars. The mouth is surrounded by tentacles. Holothurians measure between 10 and 30 centimetres long, with extremes of some millimetres for Rhabdomolgus ruber and up to more than 3 metres for Synapta maculata; the largest American species, Holothuria floridana, which abounds just below low-water mark on the Florida reefs, has a volume of well over 500 cubic centimeters, 25–30 cm long. Most possess five rows of tube feet; the podia on the dorsal surface have no locomotive role, are transformed into papillae. At one of the extremities opens a rounded mouth surrounded with a crown of tentacles which can be complex in some species.
Holothurians do not look like other echinoderms at first glance, because of their tubular body, without visible skeleton nor hard appendixes. Furthermore, the fivefold symmetry, classical for echinoderms, although preserved structurally, is doubled here by a bilateral symmetry which makes them look like chordates. However, a central symmetry is still visible in some species through five'radii', which extend from the mouth to the anus, on which the tube feet are attached. There is thus no "oral" or "aboral" face as for sea stars and other echinoderms, but the animal stands on one of its sides, this face is called trivium, while the dorsal face is named bivium. A remarkable feature of these animals is the "catch" collagen; this can be loosened and tightened at will, if the animal wants to squeeze through a small gap, it can liquefy its body and pour into the space. To keep itself safe in these crevices and cracks, the sea cucumber will hook up all its collagen fibers to make its body firm again.
The most common way to separate the subclasses is by looking at their oral tentacles. Order Apodida have a slender and elongate body lacking tube feet, with up to 25 simple or pinnate oral tentacles. Aspidochirotida are the most common sea cucumbers encountered, with a strong body and 10–30 leaf like or shield like oral tentacles. Dendrochirotida are filter-feeders, with 8 -- 30 branched oral tentacles. Sea cucumbers are 10 to 30 cm in length, although the smallest known species are just 3 mm long, the largest can reach 3 meters; the body ranges from spherical to worm-like, lacks the arms found in many other echinoderms, such as starfish. The anterior end of the animal, containing the mouth, corresponds to the oral pole of other echinoderms, while the posterior end, containing the anus, corresponds to the aboral pole. Thus, compared with other echinoderms, sea cucumbers can be said to be lying on their side; the body of a holothurian is cylindrical. It is radially symmetrical along its longitudinal axis, has weak bilateral symmetry transversely with a dorsal and a ventral surface.
As in other Echinozoans, there are five ambulacra separated by five ambulacral grooves, the interambulacra. The ambulacral grooves bear four rows of tube feet but these are diminished in size or absent in some holothurians on the dorsal surface; the two dorsal ambulacra make up the bivium. At the anterior end, the mouth is surrounded by a ring of tentacles which are retractable into the mouth; these may be simple, branched or arborescent. They are known as the introvert and posterior to them there is an internal ring of large calcareous ossicles. Attached to this are five bands of muscle running internally longitudinally along the ambulacra. There are circular muscles, contraction of which cause the animal to elongate and the introvert to extend. Anterior to the ossicles lie further muscles; the body wall consists of an epidermis and a dermis and contains smaller c
In zoological nomenclature, a type species is the species name with which the name of a genus or subgenus is considered to be permanently taxonomically associated, i.e. the species that contains the biological type specimen. A similar concept is used for suprageneric groups called a type genus. In botanical nomenclature, these terms have no formal standing under the code of nomenclature, but are sometimes borrowed from zoological nomenclature. In botany, the type of a genus name is a specimen, the type of a species name; the species name that has that type can be referred to as the type of the genus name. Names of genus and family ranks, the various subdivisions of those ranks, some higher-rank names based on genus names, have such types. In bacteriology, a type species is assigned for each genus; every named genus or subgenus in zoology, whether or not recognized as valid, is theoretically associated with a type species. In practice, there is a backlog of untypified names defined in older publications when it was not required to specify a type.
A type species is both a concept and a practical system, used in the classification and nomenclature of animals. The "type species" represents the reference species and thus "definition" for a particular genus name. Whenever a taxon containing multiple species must be divided into more than one genus, the type species automatically assigns the name of the original taxon to one of the resulting new taxa, the one that includes the type species; the term "type species" is regulated in zoological nomenclature by article 42.3 of the International Code of Zoological Nomenclature, which defines a type species as the name-bearing type of the name of a genus or subgenus. In the Glossary, type species is defined as The nominal species, the name-bearing type of a nominal genus or subgenus; the type species permanently attaches a formal name to a genus by providing just one species within that genus to which the genus name is permanently linked. The species name in turn is fixed, to a type specimen. For example, the type species for the land snail genus Monacha is Helix cartusiana, the name under which the species was first described, known as Monacha cartusiana when placed in the genus Monacha.
That genus is placed within the family Hygromiidae. The type genus for that family is the genus Hygromia; the concept of the type species in zoology was introduced by Pierre André Latreille. The International Code of Zoological Nomenclature states that the original name of the type species should always be cited, it gives an example in Article 67.1. Astacus marinus Fabricius, 1775 was designated as the type species of the genus Homarus, thus giving it the name Homarus marinus. However, the type species of Homarus should always be cited using its original name, i.e. Astacus marinus Fabricius, 1775. Although the International Code of Nomenclature for algae and plants does not contain the same explicit statement, examples make it clear that the original name is used, so that the "type species" of a genus name need not have a name within that genus, thus in Article 10, Ex. 3, the type of the genus name Elodes is quoted as the type of the species name Hypericum aegypticum, not as the type of the species name Elodes aegyptica.
Glossary of scientific naming Genetypes – genetic sequence data from type specimens. Holotype Paratype Principle of Typification Type Type genus
Holothuria forskali, the black sea cucumber or cotton-spinner, is a species of sea cucumber in the family Holothuriidae. It is found at shallow depths in the Mediterranean Sea, it is the typetaxon of the subgenus. Sea cucumbers are marine invertebrates and are related to the sea urchins and starfish. All these groups tend to be radially symmetric and have a water vascular system that operates by hydrostatic pressure, enabling them to move around by use of many suckers known as tube feet. Sea cucumbers are leathery, gherkin-shaped animals with a cluster of short tentacles at one end; this sea cucumber can grow to thirty centimetres long. It is deep brown or black but sometimes has an underlying yellowish mottling on the underside; the skin is soft yet coarse and tough and is covered with fleshy papillae which are tipped with white. The papillae are believed to be sensory organs sensitive to touch and to chemicals dissolved in the water; the underside has three rows of tube feet for walking and climbing while the upper side has two rows of rudimentary suckers.
The anterior end has a bunch of twenty yellowish retractable tentacles encircling the mouth. At the posterior, inside the body cavity, there are a bundle of Cuvierian tubules or cotton glands which can be ejected as a tangle of sticky white threads to confuse or enmesh predators; the black sea cucumber occurs around the Atlantic coasts of northwest Europe, the Canary Islands, the Azores and in the Mediterranean Sea. It is found on boulders and rocks vertical surfaces, from the intertidal zone down to a depth of about fifty metres; the black sea cucumber is a detritivore and feeds at night. When feeding, it bends its body down towards the substrate, presses the ring of oral papillae against the surface and opens its mouth wide, it extends and retracts its short tentacles and "vacuums" up sediment, extracts the nutritious part and deposits the unmetabolised portion as a sausage-like string of droppings. When not feeding, the mouth is closed and the tentacles retracted and it is difficult to tell, the head end of the animal.
Adult black sea cucumbers are either male or female. The gonads take a long time to mature and gametes are released synchronously into the water column in early spring as a result of a rise in water temperatures; the larvae become part of the zooplankton. After several moults they settle out onto the sea floor. Juveniles are seen so it is surmised that they live by day in crevices and under rocks for protection from predators whereas the adults take no particular care to remain hidden; the parasitic copepod Asterocheres boecki is an endoparasite of the black sea cucumber. It has been found that twenty-six saponins are present in the Cuvierian tubules and twelve in the animal's body wall. During stressful times, such as the presence of a predator, saponins are released into the surrounding water, it is thought that, though these are insufficient to harm a potential predator, they may serve as a warning that the cucumber is unpalatable
Invertebrates are animals that neither possess nor develop a vertebral column, derived from the notochord. This includes all animals apart from the subphylum Vertebrata. Familiar examples of invertebrates include arthropods, mollusks and cnidarians; the majority of animal species are invertebrates. Many invertebrate taxa have a greater number and variety of species than the entire subphylum of Vertebrata; some of the so-called invertebrates, such as the Tunicata and Cephalochordata are more related to the vertebrates than to other invertebrates. This makes the invertebrates paraphyletic, so the term has little meaning in taxonomy; the word "invertebrate" comes from the Latin word vertebra, which means a joint in general, sometimes a joint from the spinal column of a vertebrate. The jointed aspect of vertebra is derived from the concept of turning, expressed in the root verto or vorto, to turn; the prefix in- means "not" or "without". The term invertebrates is not always precise among non-biologists since it does not describe a taxon in the same way that Arthropoda, Vertebrata or Manidae do.
Each of these terms describes a valid taxon, subphylum or family. "Invertebrata" is a term of convenience, not a taxon. The Vertebrata as a subphylum comprises such a small proportion of the Metazoa that to speak of the kingdom Animalia in terms of "Vertebrata" and "Invertebrata" has limited practicality. In the more formal taxonomy of Animalia other attributes that logically should precede the presence or absence of the vertebral column in constructing a cladogram, for example, the presence of a notochord; that would at least circumscribe the Chordata. However the notochord would be a less fundamental criterion than aspects of embryological development and symmetry or bauplan. Despite this, the concept of invertebrates as a taxon of animals has persisted for over a century among the laity, within the zoological community and in its literature it remains in use as a term of convenience for animals that are not members of the Vertebrata; the following text reflects earlier scientific understanding of the term and of those animals which have constituted it.
According to this understanding, invertebrates do not possess a skeleton of bone, either internal or external. They include hugely varied body plans. Many have like jellyfish or worms. Others have outer shells like those of insects and crustaceans; the most familiar invertebrates include the Protozoa, Coelenterata, Nematoda, Echinodermata and Arthropoda. Arthropoda include insects and arachnids. By far the largest number of described invertebrate species are insects; the following table lists the number of described extant species for major invertebrate groups as estimated in the IUCN Red List of Threatened Species, 2014.3. The IUCN estimates that 66,178 extant vertebrate species have been described, which means that over 95% of the described animal species in the world are invertebrates; the trait, common to all invertebrates is the absence of a vertebral column: this creates a distinction between invertebrates and vertebrates. The distinction is one of convenience only. Being animals, invertebrates are heterotrophs, require sustenance in the form of the consumption of other organisms.
With a few exceptions, such as the Porifera, invertebrates have bodies composed of differentiated tissues. There is typically a digestive chamber with one or two openings to the exterior; the body plans of most multicellular organisms exhibit some form of symmetry, whether radial, bilateral, or spherical. A minority, exhibit no symmetry. One example of asymmetric invertebrates includes all gastropod species; this is seen in snails and sea snails, which have helical shells. Slugs appear externally symmetrical. Other gastropods develop external asymmetry, such as Glaucus atlanticus that develops asymmetrical cerata as they mature; the origin of gastropod asymmetry is a subject of scientific debate. Other examples of asymmetry are found in hermit crabs, they have one claw much larger than the other. If a male fiddler loses its large claw, it will grow another on the opposite side after moulting. Sessile animals such as sponges are asymmetrical alongside coral colonies. Neurons differ in invertebrates from mammalian cells.
Invertebrates cells fire in response to similar stimuli as mammals, such as tissue trauma, high temperature, or changes in pH. The first invertebrate in which a neuron cell was identified was the medicinal leech, Hirudo medicinalis. Learning and memory using nociceptors in the sea hare, Aplysia has been described. Mollusk neurons are able to detect tissue trauma. Neurons have been identified in a wide range of invertebrate species, including annelids, molluscs and arthropods. One type of invertebrate respi
Sea cucumber as food
Sea cucumbers are marine animals of the class Holothuroidea. They are used in dried form in various cuisines. In some cultural contexts the sea cucumber is thought to have medicinal value; the creature and the food product are known as bêche-de-mer in French, from Portuguese bicho do mar, trepang in Indonesian, namako in Japanese, balatan in Tagalog and loli in Hawaiian. In Malay, it is known as the gamat. Most cultures in East and Southeast Asia regard sea cucumbers as a delicacy. A number of dishes are made with sea cucumber, in most dishes it has a slippery texture. Common ingredients that go with sea cucumber dishes include winter melon, kai-lan, shiitake mushroom, Chinese cabbage. Sea cucumbers destined for food are traditionally harvested by hand from small watercraft, a process called "trepanging" after the Indonesian trepang, they are dried for preservation, must be rehydrated by boiling and soaking in water for several days. They are used as an ingredient in Chinese cuisine soups or stews.
Many commercially important species of sea cucumber are harvested and dried for export for use in Chinese cuisine as 海参. Some of the more found species in markets include: Holothuria scabra Holothuria spinifera Holothuria fuscogilva Actinopyga mauritiana Apostichopus japonicus Parastichopus californicus Thelenota ananas Acaudina molpadioidesWestern Australia has sea cucumber fisheries from Exmouth to the border of the Northern Territory; the fishing of the various species known as bêche-de-mer is regulated by state and federal legislation. Five other species are targeted in the state's bêche-de-mer harvest, these are Holothuria noblis, Holothuria whitmaei, Thelenota ananas, Actinopyga echninitis, Holothuria atra. In the far north of Queensland, sea cucumber are harvested from the Great Barrier Reef and the Coral Sea. Targeted species include Holothuria whitmaei and H. scabra. Divers are supplied air via hose or "hookah" from the surface and collect their catch by hand, diving to depths of up to 40 m.
The trade in trepang, between Macassans seafarers and the aborigines of Arnhem Land, to supply the markets of Southern China is the first recorded example of trade between the inhabitants of the Australian continent and their Asian neighbours. The Asian market for sea cucumber is estimated to be US$60 million; the dried form accounts for 95% of the sea cucumber traded annually in China, Hong Kong, Taiwan, Malaysia and Japan. It is used in Chinese cuisines; the biggest re-exporters in the trade are China, Hong Kong, Singapore. Of the 650 species of sea cucumbers, just 10 species have commercial value. In 2013, the Chinese government cracked down on the purchasing of sea cucumbers by officials as their expensive price tag could be seen as a sign of opulence. In Japan, sea cucumber is eaten raw, as sashimi or sunomono, its intestine is eaten as konowata, salted and fermented food; the dried ovary of sea cucumber is eaten, called konoko or kuchiko. Sea cucumbers are considered non-kosher in Jewish dietary law.
Both a fresh form and a dried form are used for cooking, though its preparation is complex due to its taste being "tasteless and bland". In the Suiyuan shidan, the Chinese Qing Dynasty manual of gastronomy, it is in fact stated: "As an ingredient, sea cucumbers have little to no taste, are full of sand, are remarkably fishy in smell. For these reasons, it is the most difficult ingredient to prepare well." Much of the preparation of sea cucumber goes into cleaning and boiling it stewing it in meat broths and extracts to infuse each sea cucumber with flavour. Chinese folk belief attributes male sexual health and aphrodisiac qualities to the sea cucumber, as it physically resembles a phallus, uses a defence mechanism similar to ejaculation as it stiffens and squirts a jet of water at the aggressor, it is considered a restorative for tendonitis and arthritis. Bao yu Shark fin soup Buddha Jumps Over the Wall Texts on Wikisource: "Bêche-de-Mer". Encyclopedia Americana. 1920. "Bêche-de-Mer". Encyclopædia Britannica.
1911. "Trepang". New International Encyclopedia. 1905