Marrus orthocanna | |
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Scientific classification | |
Domain: | Eukaryota |
Kingdom: | Animalia |
Phylum: | Cnidaria |
Class: | Hydrozoa |
Order: | Siphonophorae |
Family: | Agalmatidae |
Genus: | Marrus |
Species: | M. orthocanna |
Binomial name | |
Marrus orthocanna (Kramp, 1942) [1] | |
Synonyms | |
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Marrus orthocanna is a species of pelagic siphonophore, [2] [3] a colonial animal composed of a complex arrangement of zooids, some of which are polyps and some medusae. Swimming independently in the mid-ocean, it lives in the Arctic and other cold, deep waters. [4] It is a colonial creature that is born from a single egg which is fertilized. Later on, a protozoan forms that eventually grows to form more duplicating members of the colony. [5] It belongs to the order Siphonophorae and the genus Marrus, which also includes M. antarcticus, M. claudanielis, and M. orthocannoides. [6]
Like other siphonophores, Marrus orthocanna is a colony composed of a number of specialised zooids linked together by a long stem. They have different functions such as locomotion, capturing prey, waste removal, and reproduction. [7] At the front is the pneumatophore, an orange-colored, gas-filled float, the largest of which can reach estimated sizes of 5-10 centimeters in diameter [8] . Behind this is the nectosome, a region where there are a number of translucent nectophores with red, unlooped radial canals. These are bell-shaped medusae specialised for locomotion. When they contract, water is expelled which causes the colony to move. The coordinations of the medusae contractions enable the organism to swim forwards, sidewards, or backwards. The remaining region is the siphosome. Most of the zooids here are polyps, specialised for collecting food. They do this for the whole colony, spreading their single long tentacles in the water to snare prey. There are also stinging cells that release munitions of toxins that kills or paralyzes the prey. Other zooids in this region undertake digestion and assimilation of food items. Reproductive medusae are found among the polyps in the siphosome and also various other specialised zooids. The various forms are all arranged in a repeating pattern. [9] [10] The main foods of this organism are decapods, krill and other smaller crustaceans. [11]
Marrus orthocanna occurs pelagically in the mesopelagic zone of the Arctic Ocean, the north west Pacific Ocean, the Bering Sea, the Sea of Okhotsk, the north Atlantic Ocean and the Mediterranean Sea. [12] It is found at depths ranging between 200 and 800 m (660 and 2,620 ft). The greatest depth at which it has been observed is about 2,000 m (6,600 ft). [10] At these depths the temperature is about 4 °C (39 °F), hardly any light penetrates from the surface and human observation is limited to what can be seen from submersible craft. [13]
Like most other siphonophores, pelagic siphonophores are active swimmers. When its bell-shaped echo is contracted, water is pushed out causing the flock to move. The medusa's contractions are coordinated to allow the animal to swim forward, sideways, or backward. [14] ". It belongs to the family Agalmatidae, they can be found in the deep ocean waters of the Pacific and Atlantic Oceans, and they have asexual reproduction. [15]
Marrus orthocanna can reach lengths of 2-3 meters long and the tentacles can extend fifty centimeters on either side. [16] It moves forward intermittently before pausing to put out its "fishing lines", ready to ensnare passing creatures. It is a carnivore whose diet is thought to consist mainly of small crustaceans such as decapods, krill, copepods and mysids. [10]
This colonial animal arises from a single fertilised egg. The protozooid that develops from this subsequently buds to form the other members of the colony which are thus genetically identical. The protozooid first thins and elongates, the middle section becoming the stem of the colony. The pneumatophore forms at the opposite end to the mouth. Next a growth zone on the thin stem forms and budding occurs with the formation of the nectophores. As the stem continues lengthening, further zooids develop above these. Another growth zone sees the development of the siphosome and the continuing elongation of the stem carries these zooids down with it. [9] The division of labor among the zooids is an evolutionary advance in the constant struggle for existence in the deep sea. Such organisms as Marrus orthocanna blur the boundaries between the individual polyp and the whole colonial organism; each cannot exist without the other. [17] [18]
The first siphonophorae to be described was the Portuguese Man O'War in 1758 by Carl Linnaeus. Until the 19th century, only three more species were described. However in the 19th century itself, 56 new species of siphonophorae were discovered and described. The family Marrus was not discovered until the early 20th century, by A.K. Totton, a British researcher who discovered new species during his lifetime. [19] Marrus orthocanna itself was discovered by Paul Lassenius Kramp as part of the Godthaab Expedition of 1928, as they explored the area to the west of Greenland looking specifically at phytoplankton. A book about the expedition that detailed the Marrus orthocanna was released in 1942. [20]
The Portuguese man o' war, also known as the man-of-war or bluebottle, is a marine hydrozoan found in the Atlantic Ocean and the Indian Ocean. It is considered to be the same species as the Pacific man o' war or bluebottle, which is found mainly in the Pacific Ocean. The Portuguese man o' war is the only species in the genus Physalia, which in turn is the only genus in the family Physaliidae.
Hydrozoa is a taxonomic class of individually very small, predatory animals, some solitary and some colonial, most of which inhabit saline water. The colonies of the colonial species can be large, and in some cases the specialized individual animals cannot survive outside the colony. A few genera within this class live in freshwater habitats. Hydrozoans are related to jellyfish and corals and belong to the phylum Cnidaria.
Siphonophorae is an order within Hydrozoa, which is a class of marine organisms within the phylum Cnidaria. According to the World Register of Marine Species, the order contains 175 species described thus far.
Physalia is a genus of the order Siphonophorae, colonies of four specialized polyps and medusoids that drift on the surface of the Atlantic, Indian and Pacific oceans. Although these organisms look like a single multicellular organism, each specimen is actually a colony of minute organisms called zooids that have to work together for survival. A gas-filled bladder resembling a blue bottle provides buoyancy, and long tentacles of venomous cnidocytes provide a means of capturing prey. A sail on the float, which may be left or right-handed, propels Physalia about the sea, often in groups. These siphonophores sometimes become stranded on beaches, where their toxic nematocysts can remain potent for weeks or months in moist conditions. Both species of this siphonophore resemble a jellyfish in appearance, with their gas-filled float and cluster of polyps beneath, which can hang up to 30 or 165 ft below the surface of the sea.
Velella is a monospecific genus of hydrozoa in the Porpitidae family. Its only known species is Velella velella, a cosmopolitan free-floating hydrozoan that lives on the surface of the open ocean. It is commonly known by the names sea raft, by-the-wind sailor, purple sail, little sail, or simply Velella.
Praya dubia, the giant siphonophore, lives in the mesopelagic zone to bathypelagic zone at 700 m (2,300 ft) to 1,000 m (3,300 ft) below sea level. It has been found off the coasts around the world, from Iceland in the North Atlantic to Chile in the South Pacific.
Leptothecata, or thecate hydroids, are an order of hydrozoans in the phylum Cnidaria. Their closest living relatives are the athecate hydroids, which are similar enough to have always been considered closely related, and the very apomorphic Siphonophorae, which were placed outside the "Hydroida". Given that there are no firm rules for synonymy for high-ranked taxa, alternative names like Leptomedusa, Thecaphora or Thecata, with or without the ending emended to "-ae", are also often used for Leptothecata.
Marrus is a genus of siphonophores. Species include:
Agalmatidae, or Agalmidae, is a family of siphonophores.
Apolemia is a genus of siphonophores. It is the only genus in the monotypic family Apolemiidae.
Apolemia uvaria, commonly known as string jellyfish, barbed wire jellyfish, and long stringy stingy thingy, is a siphonophore in the family Apolemiidae.
Porpita prunella is a marine species of hydrozoan organisms within the family Porpitidae. It consists of colonies of zooids. Very little is known about this species, as there have been no confirmed sightings since its discovery in 1801 and naming by Haeckel in 1888. Being in the chondrophore group, it is likely that its behaviour is similar to the other species of the genera in the family. However there are also serious doubts as to its very existence as a separate species and may in fact be a synonym for Porpita porpita instead.
Bathyphysa conifera, sometimes called the flying spaghetti monster, is a bathypelagic species of siphonophore in the family Rhizophysidae. It is found in the northern Atlantic Ocean and off the coast of Southwestern Africa and California.
Physonectae is a suborder of siphonophores. In Japanese it is called 胞泳.
Calycophorae is a suborder of Siphonophores alongside two other suborders Physonectae and Cystonectae. This suborder includes the giant siphonophore, ; one of the longest lengthwise extant creatures (40–50m). While the Physonectae have a pneumatophore, nectophore, and a siphosome, Cystonectae lack a nectophore, and Calycophorae lack a pneumatophore. From the bell-shaped nectophores, Physonectae and Calycophorae are called Codonophores or Greek for bell-bearers. The distribution, morphology, and behaviors of Calycophorae species are vast and greatly depend on the species. Calycophoraes typically consist of two nectophores with a siphosome that have many tentacles that grow out of the siphosome. The Calycophoraes move by propelling water out of the nectophore much like how jellyfishes move. The tentacles act as fishing nets where the nematocysts on the tentacles paralyze their prey which are then later fed on. Calycophorae have three life stages, which are the larval development stage, the polygastric stage, and the eudoxid maturation stage. Each Calycophorae colony forms from one fertilized egg.
Nanomia bijuga, first described by Stefano Delle Chiaje in 1844 and originally named Physsophora bijuga, is a species of mesopelagic siphonophore in the family Agalmatidae As with all members of the siphonophorae order, it is a colonial organism composed of individual zooids. N. bijuga has a fairly broad distribution, and has been observed in the coastal waters off of North America and Europe. The species has been found to occupy both epipelagic and mesopelagic depths. They utilize specialized swimming zooids for both propulsion and escape behaviors. Similar to other siphonophores, Nanomia bijuga employ stinging tentacles for hunting and defense. They primarily feed on small crustaceans, especially krill.
Abylopsis tetragona is a species of siphonophore in the family Abylidae.
Lensia is a genus of hydrozoans belonging to the order Siphonoporae and the family Diphyidae. This genus is colonial and consists of many different types of highly specialized zooids. The genus Lensia was first established in 1932 by Dr. Arthur Knyvett Totton, who would also describe and add another 11 species during his career. As of March 2023, the genus consists of only 26 described and accepted species and an additional seven uncertain species, according to the World Register of Marine Species.
Tima nigroannulata, commonly known as the elegant jellyfish, is a recently discovered colonial hydrozoa found on the Pacific coast of Japan.
Praya reticulata is a species of siphonophore in the family Prayidae. It has a distinctive net of radial canals that make up its central cavity, a distinctive somatocyst that sharply doubles back, and asymmetrical canals on its bracts. The species was described by Henry Bryant Bigelow following its discovery during an expedition of the USS Albatross. The specific epithet reticulata is Latin, and comes from the word reticulatus which means "net-like". In Chinese the species is called 網管帕腊水母, which can be Romanized as wǎngguǎn pà là shuǐmǔ.