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62-503: Pelagia noctiluca is a jellyfish in the family Pelagiidae and the only currently recognized species in the genus Pelagia . It is typically known in English as the mauve stinger , but other common names are purple-striped jelly (causing potential confusion with Chrysaora colorata ), purple stinger , purple people eater , purple jellyfish , luminous jellyfish and night-light jellyfish . In Greek , pelagia means "(she) of
124-493: A " nerve net " is located in the epidermis . Although traditionally thought not to have a central nervous system , nerve net concentration and ganglion -like structures could be considered to constitute one in most species. A jellyfish detects stimuli, and transmits impulses both throughout the nerve net and around a circular nerve ring, to other nerve cells. The rhopalial ganglia contain pacemaker neurones which control swimming rate and direction. In many species of jellyfish,
186-513: A backbone, though shellfish , cuttlefish and starfish are not vertebrates either. In scientific literature, "jelly" and "jellyfish" have been used interchangeably. Many sources refer to only scyphozoans as "true jellyfish". A group of jellyfish is called a "smack" or a "smuck". The term jellyfish broadly corresponds to medusae, that is, a life-cycle stage in the Medusozoa . The American evolutionary biologist Paulyn Cartwright gives
248-408: A bell diameter of 3–12 cm (1.2–4.7 in). Their colour is variable, ranging from mauve , purple, pink, light brown to yellow. The body is radially symmetrical. There is only one body cavity known as the gastrovascular cavity. This is a primitive gut or digestive cavity with only one opening that is used for ingestion and excretion; there are four long oral arms with crenulated margins that are
310-400: A complex life cycle , and the medusa is normally the sexual phase, which produces planula larvae. These then disperse widely and enter a sedentary polyp phase which may include asexual budding before reaching sexual maturity. Jellyfish are found all over the world, from surface waters to the deep sea. Scyphozoans (the "true jellyfish") are exclusively marine , but some hydrozoans with
372-436: A few are anchored to the seabed by stalks rather than being motile. They are made of an umbrella-shaped main body made of mesoglea , known as the bell , and a collection of trailing tentacles on the underside. Via pulsating contractions, the bell can provide propulsion for locomotion through open water. The tentacles are armed with stinging cells and may be used to capture prey or to defend against predators. Jellyfish have
434-529: A free-swimming medusa is Burgessomedusa from the mid-Cambrian Burgess Shale of Canada, which is likely either a stem group of box jellyfish (Cubozoa) or Acraspeda (the clade including Staurozoa, Cubozoa, and Scyphozoa). Other claimed records from the Cambrian of China and Utah in the United States are uncertain, and possibly represent ctenophores instead. The main feature of a true jellyfish
496-593: A mauve dye in 1856–1858 referred to a color produced using the semi-synthetic dye murexide or a mixture of natural dyes. Perkin was so successful in marketing his discovery to the dye industry that his 2000 biography by Simon Garfield is simply entitled Mauve . Between 1859 and 1861, mauve became a fashion must-have. The weekly journal All the Year Round described women wearing the colour as "all flying countryward, like so many migrating birds of purple paradise". Punch magazine published cartoons poking fun at
558-408: A medusa stage in their life cycle. The basic cycle is egg, planula larva, polyp, medusa, with the medusa being the sexual stage. The polyp stage is sometimes secondarily lost. The subphylum include the major taxa, Scyphozoa (large jellyfish), Cubozoa (box jellyfish) and Hydrozoa (small jellyfish), and excludes Anthozoa (corals and sea anemones). This suggests that the medusa form evolved after
620-428: A piece of food was given to the marginal tentacle, the tentacle contracted quickly. There was a slow contraction of the coronal muscle which brought the tentacle nearer to the mouth. The food was grasped by the lip of one of the oral arm and transported slowly along until it reached the stomach. They were found to feed on the salp Thalia democratica ; however, they are found mainly to feed by taking food particle by
682-427: A planula; at this stage movement is only done by ciliary action. After a week, planulae develop into tiny ephyrae and a month later they develop into (male or female) medusae. There is little or no ephyra growth at temperatures below 10 °C (50 °F), and fewer survive below 8 °C (46 °F). The bottom-living polyp stage of most other jellyfish species is in between the planula and ephyra stages. Initially,
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#1732783796715744-562: A rash, but it is generally not dangerous and there are no known fatalities. On occasion, symptoms may be more general and include dizziness, vomiting and diarrhea. Sudden recurrent skin eruptions may occur years later. Rarely, the sting can cause a serious allergic reaction and leave scars or hyperpigmented marks on the skin that can remain for years after the encounter. If stung by P. noctiluca there can be cross-reactivity (an allergic reaction) if later stung by Portuguese man o' war ( Physalia physalis ) or sea nettles ( Chrysaora ). There
806-528: A ship's motion. This flashing is only of relatively short duration and gradually fades. A very early description of bioluminescence was provided by Pliny the Elder in Historia Naturalis (77 AD), using the name "pulmo marinus", and now considered to refer to P. noctiluca . Pelagia noctiluca is adapted to a pelagic, open-sea mode of life. Whereas most jellyfish , including the other species in
868-414: A similar appearance live in fresh water . Large, often colorful, jellyfish are common in coastal zones worldwide. The medusae of most species are fast-growing, and mature within a few months then die soon after breeding, but the polyp stage, attached to the seabed, may be much more long-lived. Jellyfish have been in existence for at least 500 million years, and possibly 700 million years or more, making them
930-450: A solid surface by a basal disk, and resemble a polyp, the oral end of which has partially developed into a medusa with tentacle-bearing lobes and a central manubrium with four-sided mouth. Most jellyfish do not have specialized systems for osmoregulation , respiration and circulation , and do not have a central nervous system . Nematocysts, which deliver the sting, are located mostly on the tentacles; true jellyfish also have them around
992-469: A variety of functions that include prey capture, defense, locomotion and attachment. When fully formed cnidae are called cnidocytes . When stimulated the cnidae secrete nematocyst toxins that are biological poisons. These organisms have a well-developed manubrium , a proboscis-like structure bearing the mouth and four long oral arms. Also the mesoglea, or jelly, is relatively thickened and well developed in this species. Sense organs, known as rhopalia in
1054-504: Is opera mauve . The first recorded use of opera mauve as a color name in English was in 1927. The color displayed at right is mauve taupe . The first recorded use of mauve taupe as a color name in English was in 1925. The color displayed at right is old mauve . The first recorded use of old mauve as a color name in English was in 1925. The normalized color coordinates for old mauve are identical to wine dregs , which
1116-463: Is a common name, its mapping to biological groups is inexact. Some authorities have called the comb jellies and certain salps jellyfish, though other authorities state that neither of these are jellyfish, which they consider should be limited to certain groups within the medusozoa. The non-medusozoan clades called jellyfish by some but not all authorities (both agreeing and disagreeing citations are given in each case) are indicated with " ??? " on
1178-530: Is also common in P. noctiluca . The stomach contents of P. noctiluca also vary throughout the seasons. Copepods tend to be their largest food source all year round, but fish eggs and pteropods are a close second. During the spring months, P. noctiluca mainly prey on copepods and fish eggs, while pteropods are preyed on more during December and May. The variability in this species' diet suggests that they are generalists, and do not have strong prey selectivity. Feeding reactions were studied by Bozler (1926), where
1240-439: Is an intermediary to a better understanding of how visual systems evolved on Earth. Jellyfish exhibit immense variation in visual systems ranging from photoreceptive cell patches seen in simple photoreceptive systems to more derived complex eyes seen in box jellyfish. Major topics of jellyfish visual system research (with an emphasis on box jellyfish) include: the evolution of jellyfish vision from simple to complex visual systems),
1302-822: Is capable of multiple task-guided behaviors. Although they lack a true brain, cnidarian jellyfish have a "ring" nervous system that plays a significant role in motor and sensory activity. This net of nerves is responsible for muscle contraction and movement and culminates the emergence of photosensitive structures. Across Cnidaria , there is large variation in the systems that underlie photosensitivity. Photosensitive structures range from non-specialized groups of cells, to more "conventional" eyes similar to those of vertebrates . The general evolutionary steps to develop complex vision include (from more ancestral to more derived states): non-directional photoreception, directional photoreception, low-resolution vision, and high-resolution vision. Increased habitat and task complexity has favored
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#17327837967151364-524: Is necessary to resolve the situation. In 2014, a second species in the genus Pelagia was described from the Mediterranean, but two years later it was moved to its own genus as Mawia benovici . The swimming ability of Pelagia noctiluca is limited and as a result large swarms (also known as blooms ) of this oceanic species are occasionally carried by the wind or current to inshore areas, sometimes ending up stranded on beaches. This also means that
1426-630: Is not met, the medusae will stop reproducing immediately and lose weight when presented with an inadequate amount of food. Large swarms of adults at the ocean surface in certain times of the year possibly are spawning aggregations. This jellyfish typically lives for about 9 months. Pelagia noctiluca are opportunistic and have been recorded feeding on a wide range of small organisms like planktonic crustaceans ( cladocerans , copepods , ostracods and crustacean larvae ), mollusk larvae, larvaceans , hydromedusae , siphonophorans , arrow worms , fish eggs and fish larvae , as well as detritus suspended in
1488-399: Is one known case where a sting by P. noctiluca caused Guillain–Barré syndrome , but all symptoms disappeared within 6 months. Peculiarly, there is a record of a seven-arm octopus "borrowing" the stinging capability of a P. noctiluca . The open-sea octopus grabbed and positioned the jellyfish in such a way that it provided a defense. The sting of P. noctiluca can possibly be relieved with
1550-409: Is the umbrella-shaped bell. This is a hollow structure consisting of a mass of transparent jelly-like matter known as mesoglea , which forms the hydrostatic skeleton of the animal. The mesoglea is 95% or more composed of water, and also contains collagen and other fibrous proteins, as well as wandering amebocytes that can engulf debris and bacteria. The mesogloea is bordered by the epidermis on
1612-475: The diel vertical migration , occurring near the surface at night and deeper during the day. Local populations fluctuate greatly and the species may go virtually unrecorded in a region for years, only to suddenly reappear in huge swarms. On occasion, a swarm may cover tens of square kilometers, include millions of Pelagia noctiluca , and reach densities of more than 500 individuals per m (14 per ft). Pelagia noctiluca are fairly small jellyfish with adults having
1674-558: The green fluorescent protein used by some species for bioluminescence . This protein has been adapted as a fluorescent reporter for inserted genes and has had a large impact on fluorescence microscopy . The stinging cells used by jellyfish to subdue their prey can injure humans. Thousands of swimmers worldwide are stung every year, with effects ranging from mild discomfort to serious injury or even death. When conditions are favourable, jellyfish can form vast swarms, which may damage fishing gear by filling fishing nets, and sometimes clog
1736-604: The amoeboid process of the endoderm cells, thus being suspension feeders. Pelagia noctiluca is considered the most important stinging jellyfish in the Mediterranean Sea. Both its tentacles and—unusual among jellyfish—the bell are covered in cnidocytes (stinging cells), and even recently dead, stranded individuals can sting. P. noctiluca contains four different types of nematocysts, but two are important for stinging, O-isorhiza and eurytele. The sting causes pain that typically lasts 1–2 weeks, local redness, swelling and
1798-452: The bell pulsates, allowing box jellyfish to swim faster than true jellyfish. Hydrozoans are also similar, usually with just four tentacles at the edge of the bell, although many hydrozoans are colonial and may not have a free-living medusal stage. In some species, a non-detachable bud known as a gonophore is formed that contains a gonad but is missing many other medusal features such as tentacles and rhopalia. Stalked jellyfish are attached to
1860-403: The common moon jelly , Aurelia aurita , which migrates in response to changes in ambient light and solar position even though they lack proper eyes. Mauve Mauve ( / ˈ m oʊ v / , mohv ; / ˈ m ɔː v / , mawv ) is a pale purple color named after the mallow flower (French: mauve ). The first use of the word mauve as a color
1922-448: The cooling systems of power and desalination plants which draw their water from the sea. The name jellyfish, in use since 1796, has traditionally been applied to medusae and all similar animals including the comb jellies ( ctenophores , another phylum). The term jellies or sea jellies is more recent, having been introduced by public aquaria in an effort to avoid use of the word "fish" with its modern connotation of an animal with
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1984-421: The exterior, perhaps supplying good oxygenation to the gonads. Near the free edges of the septa, gastric filaments extend into the gastric cavity; these are armed with nematocysts and enzyme-producing cells and play a role in subduing and digesting the prey. In some scyphozoans, the gastric cavity is joined to radial canals which branch extensively and may join a marginal ring canal. Cilia in these canals circulate
2046-694: The eye morphology and molecular structures of box jellyfish (including comparisons to vertebrate eyes), and various uses of vision including task-guided behaviors and niche specialization. Experimental evidence for photosensitivity and photoreception in cnidarians antecedes the mid 1900s, and a rich body of research has since covered evolution of visual systems in jellyfish. Jellyfish visual systems range from simple photoreceptive cells to complex image-forming eyes. More ancestral visual systems incorporate extraocular vision (vision without eyes) that encompass numerous receptors dedicated to single-function behaviors. More derived visual systems comprise perception that
2108-402: The family Pelagiidae , have a life cycle with both the free-swimming stages ( planula , ephyra and medusa ) and a bottom-living polyp stage, P. noctiluca has adapted in such a way that the polyp stage is absent. P. noctiluca reproduces sexually with the male and female spawning respectively sperm and eggs into the sea during daylight hours. After 3 days, the fertilized egg develops into
2170-400: The fluid in a regular direction. The box jellyfish is largely similar in structure. It has a squarish, box-like bell. A short pedalium or stalk hangs from each of the four lower corners. One or more long, slender tentacles are attached to each pedalium. The rim of the bell is folded inwards to form a shelf known as a velarium which restricts the bell's aperture and creates a powerful jet when
2232-910: The following phylogenetic tree by the presence of citations. Names of included jellyfish, in English where possible, are shown in boldface; the presence of a named and cited example indicates that at least that species within its group has been called a jellyfish. Anthozoa (corals) Polypodiozoa and Myxozoa (parasitic cnidarians) Staurozoa ( stalked jellyfish ) [REDACTED] Cubozoa ( box jellyfish ) [REDACTED] Discomedusae [REDACTED] Coronatae ( crown jellyfish ) [REDACTED] Aplanulata [REDACTED] Siphonophorae [REDACTED] Some Leptothecata e.g. crystal jelly [REDACTED] Filifera e.g. red paper lantern jellyfish [REDACTED] Limnomedusae , e.g. flower hat jelly [REDACTED] Narcomedusae , e.g. cosmic jellyfish [REDACTED] The subphylum Medusozoa includes all cnidarians with
2294-572: The following cladogram of the animal kingdom: Porifera Ctenophora (comb jellies) ??? [REDACTED] Cnidaria [REDACTED] (includes jellyfish and other jellies) Protostomia Ambulacraria Tunicata (includes salps ) ??? [REDACTED] Vertebrata Jellyfish are not a clade , as they include most of the Medusozoa, barring some of the Hydrozoa. The medusozoan groups included by authorities are indicated on
2356-497: The following general definition: Typically, medusozoan cnidarians have a pelagic , predatory jellyfish stage in their life cycle; staurozoans are the exceptions [as they are stalked]. The Merriam-Webster dictionary defines jellyfish as follows: A free-swimming marine coelenterate that is the sexually reproducing form of a hydrozoan or scyphozoan and has a nearly transparent saucer-shaped body and extensible marginal tentacles studded with stinging cells. Given that jellyfish
2418-510: The high-resolution visual systems common in derived cnidarians such as box jellyfish . Basal visual systems observed in various cnidarians exhibit photosensitivity representative of a single task or behavior. Extraocular photoreception (a form of non-directional photoreception), is the most basic form of light sensitivity and guides a variety of behaviors among cnidarians. It can function to regulate circadian rhythm (as seen in eyeless hydrozoans ) and other light-guided behaviors responsive to
2480-423: The huge popularity of the colour: “The Mauve Measles are spreading to so serious an extent that it is high time to consider by what means [they] may be checked.” But, because it faded easily, the success of mauve dye was short-lived; by 1873, it was replaced by other synthetic dyes. As the memory of the original dye soon receded, the contemporary understanding of mauve is as a lighter, less-saturated color than it
2542-646: The intensity and spectrum of light. Extraocular photoreception can function additionally in positive phototaxis (in planula larvae of hydrozoans), as well as in avoiding harmful amounts of UV radiation via negative phototaxis . Directional photoreception (the ability to perceive direction of incoming light) allows for more complex phototactic responses to light, and likely evolved by means of membrane stacking. The resulting behavioral responses can range from guided spawning events timed by moonlight to shadow responses for potential predator avoidance. Light-guided behaviors are observed in numerous scyphozoans including
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2604-436: The interradial sectors of the stomach wall slightly distal to the rows of gastric filaments. Male and female gonads vary only slightly and the main difference is the thickness of the follicle. Pelagia noctiluca are bioluminescent , i.e. have an ability to produce a low light that is visible to humans during the night. Light is emitted in the form of flashes when the medusa is stimulated by turbulence created by waves or by
2666-532: The locations are California (rare), Hawaii (rare), northern New Zealand and all around Australia (common). However, it is suspected that Pelagia noctiluca —as currently defined—is a species complex with records outside the North Atlantic region involving other closely related species that presently are unrecognized or undescribed . Even North Atlantic and South Atlantic populations show significant genetic differences. A comprehensive taxonomic review
2728-455: The medusa of P. noctiluca only has a bell diameter of about 1 cm (0.4 in). Some already reach maturity at 3.5 cm (1.4 in) in bell diameter and at 6 cm (2.4 in) all are mature. In the Mediterranean Sea, P. noctiluca appear to mostly spawn between the late summer and early winter, but also at lower levels in the spring to early summer. P. noctiluca rely on favorable trophic conditions to spawn, so when their criteria
2790-627: The most studied jellyfish species. This jellyfish is best known from the North Atlantic region, ranging from 4th parallel north (just north of Equator ) to the North Sea and Atlantic Canada , including the Mediterranean and Gulf of Mexico . There are reports from most other tropical or warm temperate seas around the world, including both the Pacific and Indian Oceans, with its apparent southern limit being 42nd parallel south . Some of
2852-470: The mouth and stomach. Jellyfish do not need a respiratory system because sufficient oxygen diffuses through the epidermis. They have limited control over their movement, but can navigate with the pulsations of the bell-like body; some species are active swimmers most of the time, while others largely drift. The rhopalia contain rudimentary sense organs which are able to detect light, water-borne vibrations, odour and orientation. A loose network of nerves called
2914-447: The mouth, which also functions as the anus, at its tip. There are often four oral arms connected to the manubrium, streaming away into the water below. The mouth opens into the gastrovascular cavity , where digestion takes place and nutrients are absorbed. This is subdivided by four thick septa into a central stomach and four gastric pockets. The four pairs of gonads are attached to the septa, and close to them four septal funnels open to
2976-506: The oldest multi-organ animal group. Jellyfish are eaten by humans in certain cultures. They are considered a delicacy in some Asian countries, where species in the Rhizostomeae order are pressed and salted to remove excess water. Australian researchers have described them as a "perfect food": sustainable and protein-rich but relatively low in food energy . They are also used in cell and molecular biology research, especially
3038-402: The open lagoon, where they feed, and back again. Box jellyfish have more advanced vision than the other groups. Each individual has 24 eyes, two of which are capable of seeing colour, and four parallel information processing areas that act in competition, supposedly making them one of the few kinds of animal to have a 360-degree view of its environment. The study of jellyfish eye evolution
3100-456: The open water and microscopic phytoplankton . The phytoplankton can be consumed either directly or indirectly by eating herbivorous crustaceans with stomachs filled with it. The ability to eat phytoplankton is—as far as known—highly unusual among cnidarians . P. noctiluca will eat small warty comb jellies ( Mnemiopsis leidyi ), potentially helping to control this invasive species . Cannibalism where adults consume young of their own species
3162-415: The outside and the gastrodermis on the inside. The edge of the bell is often divided into rounded lobes known as lappets , which allow the bell to flex. In the gaps or niches between the lappets are dangling rudimentary sense organs known as rhopalia , and the margin of the bell often bears tentacles. On the underside of the bell is the manubrium, a stalk-like structure hanging down from the centre, with
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#17327837967153224-448: The polyps. Medusozoans have tetramerous symmetry, with parts in fours or multiples of four. The four major classes of medusozoan Cnidaria are: There are over 200 species of Scyphozoa, about 50 species of Staurozoa, about 50 species of Cubozoa, and the Hydrozoa includes about 1000–1500 species that produce medusae, but many more species that do not. Since jellyfish have no hard parts, fossils are rare. The oldest unambiguous fossil of
3286-477: The primary feeding surface. Each P. noctiluca medusa has eight long tentacles that emerge from the umbrella margin. Being radially symmetrical it has no head and thus no centralized nervous system. The nervous system present is primitive, consisting of a simple net composed of naked and largely non-polar neurons . In addition P. noctiluca also lacks a gaseous exchange, excretory and circulatory system. However cnidaria have evolved cnidae, cells which serve for
3348-404: The rhopalia include ocelli , light-sensitive organs able to tell light from dark. These are generally pigment spot ocelli, which have some of their cells pigmented. The rhopalia are suspended on stalks with heavy crystals at one end, acting like gyroscopes to orient the eyes skyward. Certain jellyfish look upward at the mangrove canopy while making a daily migration from mangrove swamps into
3410-399: The scyphomedusae, are located around the umbrella margin in notches and alternate between tentacles. Cnidae are present in the epidermis and gastrodermis of the umbrella, as well as on the tentacles. Pelagia noctiluca has eight marginal tentacles alternating with eight marginal sense organs. Four gonads arise as elongated endodermal proliferations, developing into ribbon-like folds in
3472-728: The sea", from pelagos "sea, open sea"; in Latin noctiluca is the combining form of nox , "night"", and lux , "light"; thus, Pelagia noctiluca can be described as a marine organism with the ability to glow in the dark ( bioluminescence ). It is found worldwide in tropical and warm temperate seas, although it is suspected that records outside the North Atlantic region, which includes the Mediterranean and Gulf of Mexico , represent closely related but currently unrecognized species. A fairly small and variably coloured species, both its tentacles and (unusual among jellyfish) bell are covered in stinging cells . Stinging incidents are common, painful and
3534-582: The species sometimes appears in waters outside its normal temperature preference, with records as far north as the Shetland Islands and the Norwegian deep . It generally occurs at water temperatures between 10 and 27 °C (50–81 °F), but below 11 °C (52 °F) it stops pulsating. It mostly ranges from the surface to a depth of 150 m (490 ft), but has been recorded to 1,400 m (4,600 ft). Pelagia noctiluca partakes in
3596-470: The symptoms may continue for a considerable time after the encounter, but they are generally not dangerous. When large numbers of this oceanic species are washed ashore, the local economy can be affected because tourists avoid the beaches and fishers are stung while trying to retrieve their nets, which can be clogged by the jellyfish. Additionally, swarms of Pelagia noctiluca have been recorded wiping out entire fish farms . Because of this, it has become one of
3658-406: The use of Hydroxyacetophenone and Symsitive® since they are nematocyst inhibitor compounds, meaning they inhibit the discharge of cnidocysts. Jellyfish Jellyfish , also known as sea jellies , are the medusa -phase of certain gelatinous members of the subphylum Medusozoa , which is a major part of the phylum Cnidaria . Jellyfish are mainly free-swimming marine animals , although
3720-479: Was first so named in 1859. Chemist William Henry Perkin , then 18, was attempting to synthesize quinine in 1856; quinine was used to treat malaria . He noticed an unexpected residue, which turned out to be the first aniline dye. Perkin originally named the dye Tyrian purple after the historical dye, but the product was renamed mauve after it was marketed in 1859. It is now usually called Perkin's mauve , mauveine , or aniline purple . Earlier references to
3782-540: Was in 1796–98 according to the Oxford English Dictionary , but its use seems to have been rare before 1859. Another name for the color is mallow , with the first recorded use of mallow as a color name in English in 1611. Mauve contains more gray and more blue than a pale tint of magenta . Many pale wildflowers called "blue" are more accurately classified as mauve. Mauve is also sometimes described as pale violet . The synthetic dye mauve
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#17327837967153844-618: Was originally known. The 1890s are sometimes referred to in retrospect as the " Mauve Decade " because of the popularity of the subtle color among progressive artistic types, both in Europe and the US. The color displayed at right is the rich tone of mauve called mauve by Crayola . The color displayed at right is the deep tone of mauve that is called mauve by Pourpre.com , a color list widely popular in France . The color displayed at right
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