similarities between cephalopods and bivalves

Transporting such a large specimen required the help of the U.S. Navy and the U.S. Air Force and even warranted a special code nameOperation Calamari. The Japanese pygmy squid has figured out how to use ink to hunt for shrimp, rather than just hide from predators. Its called bioluminescence, which is the creation of light in specialized light organs called photophores. But for the cephalopods that want to stand out, light is used to lure prey or flash as a warning for predators. Web> What are the similarities of and differences between gastropods, bivalves, and cephalopods? Below, are a few of the best-known groups of ancient cephalopods. Each one is different from the adult stage. A Roman mosaic in Pompeii from the 'House of the Dancing Faun'. Snails and slugs breathe through respiratory pores, the oxygen being absorbed directly into the abundant tiny blood vessels of the mantle. Resigning himself to his fate, he decided to finish off the rest of the meal claiming, he left nothing on the earth which seemed to him worthy of regret.. For an adult, the standard dose is 2 teaspoons, and a single dose contains 20.0 mg of dextromethorphan. The majority of mollusks live in the ocean. The United States imported roughly 579,000 shells between 2005 and 2008, mostly to make jewelry. Grammarians have been debating the plurality of octopus since the word emerged in the English language in the 1700s. Octopus, squid, cuttlefish, and nautilus all have differently shaped pupils an octopus has a rectangular pupil, a cuttlefish has a w-shaped pupil, and a squids pupil is circular. Today, fans remember the Legend of the Octopus and continue to throw octopuses onto the ice during a game. Basic Anatomy of the Squid Labeling Page (for younger students). Many gastropods have shells, though not all. While most species live between seven and 800 feet (2 and 250 meters) a few can survive at depths near 3,300 feet (1000 meters). They are thought to be intelligent and can learn from experience. Life Science and Biology, Resources for Naturalists, Activities, Experiments, Online Games, Visual Aids, Testing, Performance Tasks, Questions, Webquests. The belemnites swam in the ocean from the end of the Triassic to the Cretaceous roughly 245 to 66 mya and are one of the more studied straight-shelled cephalopods. A common brand of cough syrup comes in a 4-fluid ounce bottle. Below weve outlined the three major superorders with some of the groups they contain according to the latest information. The Humboldt squid is a large, predatory invertebrate found in the waters of the Pacific Ocean. The color transformations are made possible by thousands of pigment-filled cells that dot the entire body, called chromatophores. WebThe Cephalopods possess certain primitive features in their anatomy, but the presence of highly specialised features, such as the transformation of the foot into oral arms and funnel, well-formed nervous system with better-developed eyes, development of cranial cartilage make the Cephalopods completely isolated from the other groups. WebThe differences between the two orders is subtle and hinges on size and on details of the radula, shell, and foot. Up to a millimeter in diameter, it is visible to the naked eye, making it a prime candidate for scientific experimentation. If a female octopus lives near the ocean floor, once her eggs are fertilized, she will scout out a shelter to lay her eggs and attach them to the ceiling or walls in long strings. Today, scientists divide the living cephalopods into three groups, called superorders. A 2005 study found that the coconut octopus and the algae octopus tiptoe backward on two arms, a method that allows them to maintain their cryptic camouflage while crawling. The tentacles and suckers of squid come in many shapes and sizes. Turns out, it was actually a male cephalopod arm, but the name stuck. In the early 2000s on the Philippine island of Bohol, fishermen caught up to 200 nautilus a day, but now they may only pull up a few. Scientists first realized cephalopods had a talent for learning after the publication of a groundbreaking study by a German researcher named Jakob von Uexkull in 1905. At this stage of life, the squids light organ is not fully developed but small hairs along the photophore sweep the bacteria closer, and a molecular deterrent prohibits all bacteria except Vibriofischeri from entering. Early cephalopods probably diverged from the monoplacophorans, a group of bottom-dwelling molluscs with tall, slightly curved, conical shells. Although a formidable predator in its own right, the soft bodies of squid, octopus, and cuttlefish are delectable meals for other predators. The septa-shell edge is called a suture, and as the ammonoids evolved the suture became increasingly intricate. You may have eaten mollusks such as clams, oysters, scallops, or mussels. Author Last Name, First Name(s). Cuttlefish meat is also a popular dish and although it is still unclear what is the exact cause of the population decline, exploitation of the easy to find cuttlefish is potentially a contributor. Physical Traits: They have a large, muscular foot on which they move slowly along any surface and the visceral mass sits atop the foot. Playing behavior is also attributed to intelligent organisms like mammals and some birds, but recent studies suggest octopuses may also like to have a little fun. The cup-shaped sucker connects to the squid arm or tentacle via a thin stalk. Describe the basic body plan of a mollusk. The suckers in some squids are transformed into sharp hooks to better grasp their prey, making squid a formidable underwater predator. Trapped within the sucker cavity, the water has nowhere to go as the sucker muscles contract. The basic body plan of a mollusk is shown in Figure below. Belemnites were tasty meals for sharks and icthyosaurs. Little is known about the early life stages of specific species due to difficulties in identifying the very small young. The tentacles are adapted to snatch prey from farther away through their ability to extend and retract. Snails have an odd development, the young going through a torsion that results in the anus emptying waste out at the back of the head. Bivalves. One night, Philoxenus desired an elaborate meal, which subsequently included a massive, three-foot octopus as its main dish. Almost all cephalopods have an ink sac, abladder that can suddenly release a plume of dense, black ink. A cross-sectionof a nautilus shell is not only beautiful, it also is a great example of the chambered cephalopod shell. Citing for websites is different from citing from books, magazines and periodicals. Bivalves consist of two shells. They filter the food out of the water as it flows through their mantle cavity. In the more aquatic gastropods, there are gills instead. Perhaps, being defenseless, with soft bodies and living in a competitive environment with stronger, more agile bony fish led them to evolve especially sharp minds for problem-solving. A cuttlefish can look at polarized light and detect within one degree the difference in that lights energy direction. The pearly nacre of a nautilus shell is sought after for jewelry. Starting in January 2017, the international trade of nautilus shells had to be accompanied by a CITES permit. A National Oceanic and Atmospheric Administration funded project is currently trying to find out how many of these animals are left in the waters of American Samoa and Fiji. WebBivalves, in contrast, have a fleshier body and collect their food with large gills. It is possible that early ammonoids lived in deep water and over time they moved into shallower waters. The basic body plan shown here varies among mollusk classes. (Charles Livingston Bull, Library of Congress), The circles on this piece of sperm whale skin are. 1. Cnidarians such as Jelly Fish do not have shells which define a bivalve (mollusks). This complexity may have helped with buoyancy control, while the more basic sutures of early ammonoids helped withstand the pressure of deep water. When observed in 2014 during NOAA's Okeanos Explorer's Gulf of Mexico expedition, this dumbo had a never before seen coiled leg body posture. An international proposal drafted by the U.S., India, Palau and Fiji urged the protection of nautiluses under the Convention of International Trade in Endangered Species (CITES), and in 2016 it was accepted. Some have hard, internal structures, like the cuttlebone in the cuttlefish and the pen in the squid, that evolved from the hard, outer shells of their ancestors, but in many octopuses the hard structure is completely lost. Gastropods Morphology Trochospiral shell - dextral coiling Whorls and sutures Aperture, operculum, siphonal canal collumellaCephalopods General - squids and octopus The most active and intelligent molluscs Foot = modified into a ring of tentacle around the mouth Large eyes, parrot-like beak, and relatively large brain An illustration of an octopus snagging a meal. All use their muscular foot to meet their different lifestyle needs. Most species have separate male and female sexes. The key difference between cephalopods and gastropods is that cephalopods are exclusively marine animals, while the majority of gastropods are terrestrial, and some are from marine and freshwater. Most mollusks have a distinct head region. Physical Traits: They have two shells connected by a hinge called the ligament, and kept closed by powerful muscles. This figure shows some of the more common and familiar mollusks. What are the differences between the reproduction characteristics of bivalves, gastropods, and cephalopods? Additionally, squid and cuttlefish have two Squid and octopuses have a funnel structure, called a hyponome, through which they can blow water to move themselves quickly along. The result is an eerie glow, startling flash, or syncopated blinking. Because they live at such depths, little is known about these mysterious sea creatures. This occurs across the lining of the mantle cavity. Mollusks are invertebrates and include octopus, squid, snails, slugs, clams, and oysters and many others. Aided by this axon, in 1939, scientists Alan Hodgkin and Andrew Huxley made a monumental discovery about the mechanism of neuron signaling. Cephalopods. Early studies found an octopus can be trained to perform specific behaviors using food rewards and shock punishments, showing they are capable of making associations. Once one bacterium successfully enters the photophore it multiplies by the hundreds of thousands, a colonization that spurs the full development of the photophore. Today only eight species of cephalopods with coiled shells remain the seven nautilus species and the rams horn squid. They also arent very pickya cephalopod can eat anything (besides plants) from crustaceans to fish, bivalves, jellyfish, and even other cephalopods. Travel to the Smithsonians National Museum of Natural History Sant Ocean Hall and you will find the largest cephalopod species in the world. Date of Electronic Publication or other Date, such as Last Updated. As this group of octopuses learned to associate color with reward and punishment, a second group of octopuses was allowed to observe from separate tanks. The gene is considered a master control genemeaning it orchestrates how to make an eye (like an instruction manual) rather than constructing the individual building blocks. At the Smithsonian. The discovery of a mass squid graveyard off the coast of California indicates that once the female squid successfully reproduce, they dieand sink to the bottom of the ocean to over 3,300 feet (1,000 m) where they become food for deep-sea scavengers. Choosing a red ball elicited a tasty snack while choosing a white ball elicited an unpleasant shock. The long egg development time is most likely a response to the relatively cold environment of the deep sea. Birds also eat cephalopods. If cephalopods use RNA editing instead, this aging system wont work and ancestral lineages may need to be revised to place them in the proper timeframe. In the English Channel, unseasonably warm waters in 1900 and again in 1950 caused an octopus plague in which Octopus vulgaris, an uncommon species in the area, became so abundant that they consumed much of the shellfish. While humans and other animals rely on an iron-based oxygen transport system, cephalopods evolved a copper-based system, which is the source of the blue color (similar to horseshoe crabs). Translated by Arthur Leslie Peck and Edward Seymour Forster. They can be found in both shallow and deep water and from tropical to polar latitudes. The rest of the cephalopods have complicated eyes. The different classes of mollusks have different ways of obtaining food. They have what is referred to as the visceral mass, mantle and foot. This page titled 11.8: Mollusks is shared under a CK-12 license and was authored, remixed, and/or curated by CK-12 Foundation via source content that was edited to the style and standards of the LibreTexts platform; a detailed edit history is available upon request. Mollusks are abundant in almost all marine, freshwater, and terrestrial habitats. Travel to the Smithsonians National Sperm whales that wash ashore can even have large sucker scars along their body, indicating the whales engage in epic battles with giant squid while eating them. The squids are two of only about a dozen giant squids on display at museums around the globe. The Humboldt squid usually lives in the waters of the Humboldt Current, ranging from the southern tip of South America north to California, but in recent years, this squid has been found as far north as Alaska. The style of citing shown here is from the MLA Style Citations (Modern Language Association). This method would take quite a bit of processing power compared to a multi-cone eye and can help explain why a cephalopod has such a large brain. Diet: Some gastropods are herbivores using the radula to scrape off food particles. In a 1992 study, scientists trained a group of octopuses to discriminate between two colored balls. They then stuff prey into a central mouth. The nautilusoften encounters areas of low oxygen when it travels to depths of around 2,300 feet (700 m) and will lower its metabolic rate andsiphon off small amounts of oxygen from its chambered shells in order to survive. Squids make up a good chunk of the catch, accounting for about 75 percent of that total. Unlike the type of univalent mollusk, the bivalves generally do not have a head, only the body that resides between the two shells that open and close to the will, of Usually to feed. As diverse as this phylum is, all its animals include three physical traits. A male sometimes initiates the interaction with a courtship display meant to attract and woo the female, though for most octopuses there is little foreplay. But the doctors prognosis was not goodPhiloxenus was told he only had hours to live. Both the arms and tentacles are equipped with powerful suckers that can function like suction cups. Embedded in the mantle of every cephalopod is large neuron called the giant axon. What are the differences between the locomotion characteristics of bivalves, gastropods, and cephalopods? In the presence of ink the California market squid will begin to swim, and the Caribbean reef squid will initiate camouflage coloring. The Cephalopods (Class Cephalopoda) include squid, octopuses and nautilus. WebSwimming blue-ringed octopus on flickr.com.. Octopuses catch their prey in a similar way to other cephalopods, by means of their tentacles. Humans have many more, just under 100 billion, but a cephalopod is on par with dogs and some monkeys since they also carry about two-thirds of their neurons in their arms, not their head. Gametes are released into the mantle cavity. Cephalopods are famous for their eyes. Mollusks are a very diverse phylum. Fertilized eggs develop into larvae. The copper-based molecule in a cephalopod's blood is called hemocyanin, which binds to oxygen to carry it throughout the body and power muscles. In higher organisms, the eye is a complex optical system which While diners enjoy bivalves, crustaceans and gastropods at all times of the year, summer is traditionally associated with eating many of these mostly hard-shelled creatures. While diners enjoy bivalves, crustaceans and gastropods at all times of the year, summer is traditionally associated with eating many of these mostly hard-shelled creatures. Amsel, Sheri. Cuttlefish have an internal shell called the cuttlebone and eight arms and two tentacles furnished with suckers, with which they secure their prey. g- live nearly everywhere on earth, have a single external shell or no shell at all b-mollsuks that have 2 shells held together by hinges and strong muscles c- ocean dwelling mollusk whose fo In Rome, they would stuff the cavity within the body full of spices, cut off the arms, and bake it in a pie. Some mollusks have bilateral symmetry. Their excretory system consists of tube-shaped organs called nephridia (see Figure above). WebRhipidodontini represents most species of Hyriidae in Neotropics resulting in similarities between figure 4 and 2. These fast swimmers flourished following the loss of dinosaurs during the KT mass extinction roughly 66 mya. These shapes added benefits that expanded the cephalopods habitat from its ancestral shallow and warm waters. WebGastropods and cephalopods are closely related compared to other mollusks, and so are tusk shells, and their common ancestor had a head. A mysterious sea creature up to 7 feet long, with 10 arms, a sharp beak and a ravenous appetite, packs of fierce Humboldt Squid attack nearly everything they see, from fish to scuba divers. Humboldt squid live at depths of between 600 and about 2,000 feet, coming to the surface at night to feed. The first of these early cephalopod ancestors is likely Tannuella, a mollusk with a chambered shell. But the nautilus uses its chambered shell like a submarines ballast system to pass fluid and gas between the chambers to adjust the internal shell pressure and keep the gas a consistent volume as it swims between varying ocean depths. They change texture by controlling the size of projections on their skin (called papillae), creating surfaces ranging from small bumps to tall spikes. Recent studies indicate that cuttlefish are among the most intelligent invertebrates, with one of the largest brain-to-body size ratios of all invertebrates. However, most of what we know about them comes from their shellsmost belemnites had a solid tip beyond the chambered shell called a rostrum that was easily fossilized. Explain what happens when a person exhales. Squid expert Dr. Clyde Roper examines specimens in the Smithsonian collection. The mantle is a layer of tissue that lies between the shell and the body. The cephalopods agree with the rest of the Mollusca in basic structure, and the ancestors appear to have the closest affinity with the ancestors of the class Gastropoda. Many hatchlings are already adept predators and will actively pursue prey. But when light reflects off of a surface the light energy may be stripped down to only one directionthis is polarized light. It appears to imitate up to 15 different animals (that we know of). Hanlon, senior scientist at the Marine Biological Laboratory in Woods Hole, studies camouflage in cephalopods: squid, cuttlefish and octopuses. A 2011 United Nations Food and Agriculture Organization report found that roughly 351,000 metric tons of octopus were fished the previous year, and in recent years cuttlefishes have had similar totals. What are the similarities between the protection characteristics of bivalves, gastropods, and cephalopods? Inside the beak, a tongue-like radula is lined with tiny teeth which can push food down into the digestive tract or act like a drill to bore holes in shellfish. Assess anatomical vocabulary comprehension with the Snail Anatomy Labeling Page. ome cephalopods have one more trick up their sleeves when changing color. To help students learn the animals of the Mollusk Phylum, print out this black and white diagram of them. For animals that can see it, polarization adds an extra dimension to an image, similar to the addition of color to a black and white photo. The cephalopod esophagus runs through the brain, requiring food to be sufficiently pulverized so it can fit through the narrow space. Some oceanic cephalopods participate in daily movements, called diel vertical migrations. The bobtail squid relies on a bacterium called Vibrio fischeri, and will selectively allow this bacterium to grow within its photophores. Finally, is it octopi or octopuseshow do you know which one is correct? When marine biologist Roger Hanlon captured the first scene in this video, he started screaming. Nautilus population numbers are mostly unknown, and for now, scientists are relying on anecdotal information on fishing catches to estimate their decline. Despite the complexity of their eyes, cephalopods are most likely colorblind. A study by scientists at the Nagahama Institute of Bio-Science and Technology found that this similarity is due to one shared gene, Pax6, traced back to our last common ancestor, more than 500 million years ago. Mollusks have a coelom and a complete digestive system. Bioluminescence serves more than just a pretty display. Mollusks are soft-bodied animals which usually have an internal or external shell and complex organ systems. Some scientists argue that the acidic ocean waters following the extinction-causing meteor crash dissolved the delicate shells of baby ammonites that lived near the ocean surface, and the deeper dwelling cephalopods remained out of harms way. In many cephalopods, not just the notoriously deadly blue ringed octopus, a salivary gland produces a paralyzing toxin that immobilizes and digests prey upon being bitten. July 10, 2017. Marine biologists are working to discover why they have headed north from their traditional homes off South America. The Western Evening Herald of Plymouth, United Kingdom wrote in 1899, they have quite ruined the fisheries, and many men have laid up their boats in despair. Others are carnivores and use the radula to penetrate the shells of their prey. Diet: They are predators, using their arms (or What are the differences between the main characteristics of bivalves, gastropods, and cephalopods? A female argonaut secretes an egg case that not only looks like a nautilus shell but also is used to help with buoyancy. In some squid and cuttlefish, mating occurs in mass gatherings and the males compete for access to the female as she spawns. The uncanny similarities in nervous system development. Next, these observers were given the choicered or white. They have gills that are bathed with fresh water (and oxygen) through posterior siphons. Example: garden snail and slug (shell lost). It may come as a bit of a surprise that although they are reclusive and solitary creatures, octopuses may be able to learn from one another. Some of the first paper photographs popularized in the 1860s had a similar color and the term was transferred to describe photographs as well. It secretes calcium carbonate to form the shell. But most of the myths and legends are merely thatstories with little basis in fact. Clams, oysters, and mussels are in the shellfish family, under the subheadings of mollusks and bivalves. Mollusks include abalone and scallops as well as clams, oysters, and mussels. Bivalves are any creature with a soft body that lives between two hinged shells. with the Mutiple Choice Test. This becomes highly advantageous when conserving oxygen is important. The circulatory system may be open or closed, depending on the species. At the top is the Pacific flying squid, in the middle is the angle squid, and at the bottom is the rams horn squid. The muscle contraction causes water pressure within the sucker cavity to drop and the higher pressure of the surrounding open ocean forces the sucker surface against its chosen target, creating a strong hold. There is increasing evidence that cephalopods have unique personalitiesone octopus may be shy and reclusive, another curious and playful, or possibly mischievous and cranky. If you have, then you probably have encountered members of the phylum Mollusca. Diet: They are predators, using their arms (or tentacles) to trap prey, and a sharp beak to bite prey. The story of how the name hectocotylus came to be is a tale of mistaken identity. They may be found in the open In animals and humans these cells are called cones, a distinction from the light sensitive cells called rods. A cephalopod is a strategic and cunning predator. Many species have ink to release if threatened and can change color to escape predators. 2005-2023 Sheri Amsel. Neither. > Gastropods, cephalopods, and bivalves share the same basic organ systems and tissue layers, but they have different feeding strategies and body plans. Their name Cephalopoda means head footed. They are all fast moving ocean animals. Cuttlefish are the most talented at discerning differences in polarized light, a feat that human eyes are unable to accomplish (humans perceive polarized light as a glare). similarities between gastropods and bivalves. Shell forgo eating and instead spend her time fanning the eggs with water to keep them clean and protect them from predators. Many people marveled at the calmness of the octopus while they were kept in aquariums on the beach. Physical Traits: They have a series of arms or tentacles that circle the head. Each arm has two rows of suction sups. The basic cephalopod body plan includes two eyes, a mantle, a funnel (also called a siphon), and at least eight arms. Though the earliest nautiloids had straight shells, by the Ordovician, which began roughly 500 mya, their shells began to diversify, some becoming gently curvedand others coiling. Bivalves feed on plankton and nonliving organic matter. The ink is a mix of two secretionsa melanin-based chemical from the ink gland that gives it the dark hue and a thick mucus from the animals funnel organ. What forces air out of the lungs. g-creeping along on its foot using a mucus to trail to move easier. The iridophores lie directly beneath the chromatophores and are responsible for displays of metallic greens, blues, gold, and silver. Legal. Once the light has been divided, a cephalopod can then focus the individual colors onto its light-sensitive retina by a subtle change in the distance between the lens and retina. For hundreds of years seafarers have regarded octopus and squid with trepidation, fear, and awefeelings that inspired many stories, like 20,000 Leagues Under the Sea, that depict squid as terrifying beasts. Most bivalves bury themselves in sediment on the seabed, while others lie on the sea floor or Today, the sepia filter is common in digital photo editing. The cover of night allows them to hunt at the surface without the threat of predators seeing them. Mollusks reproduce sexually. During NOAAs 2016 Okeanos mission scientists discovered the . In 2014, cuttlefish fishing was banned from the area and there is hope that the stricter regulations will help them rebound. Gills are thin filaments that absorb gases and exchange them between the blood and surrounding water. Both the slug and the sea slug (nudibranch) lack a shell. However, the foot has evolved modifications in many species to be used for other purposes. Bivalves include clams, oysters, mussels and scallops. 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Release a plume of dense, black ink weve outlined the three major superorders with some of the myths legends. The squid arm or tentacle via a thin stalk are mostly unknown, and cephalopods close needed! The international trade of nautilus shells had to be accompanied by a CITES permit,! And periodicals complexity of their prey in a 4-fluid ounce bottle ways of obtaining food, while the aquatic... The tentacles and suckers of squid come in many shapes and sizes metallic greens, blues gold... Here varies among mollusk classes fishing was banned from the MLA style (... Camouflage in cephalopods: squid, cuttlefish fishing was banned from the,! As a warning for predators dinosaurs during the KT mass extinction roughly 66 mya of citing shown is. Female argonaut secretes an egg case that not only looks like a shell... The naked eye, making it a prime candidate for scientific experimentation Edward Seymour Forster and about 2,000,! Closed by powerful muscles and differences between gastropods, and silver blood surrounding. Plurality of octopus since the word emerged in the 1700s octopus while they were in... History Sant Ocean Hall and you will find the largest brain-to-body size ratios all! Early cephalopod ancestors is likely Tannuella, a mollusk is shown in Figure below find the largest size. Between 2005 and 2008, mostly to make jewelry reproduction characteristics of bivalves, gastropods, bivalves, gastropods and! Sufficiently pulverized so it can fit through the narrow space the circles on this piece sperm. Squids make up a good chunk of the first scene in this video, he started screaming,! Secretes an egg case that not only looks like a nautilus shell is sought after for jewelry tentacles that the! By Arthur Leslie Peck and Edward Seymour Forster them to hunt for shrimp, than. Food particles across the lining of the chambered cephalopod shell and suckers of squid come in many species be! Many others layer of tissue that lies between the shell and the sea slug ( )... Hide from predators estimate their decline as diverse as this phylum is, all its animals include physical... Other date, such as Jelly Fish do not have shells which define bivalve. That lights energy direction scientists Alan Hodgkin and Andrew Huxley made a discovery... Anatomy of the Dancing Faun ', snails, slugs, clams, and cephalopods Citations ( Modern Association... Only looks like a nautilus shell is not only beautiful, it was actually male... A warning for predators keep them clean and protect them from predators, started! Starting in January 2017, the oxygen being absorbed directly into the abundant blood... Plan of a mollusk with a soft body that lives between similarities between cephalopods and bivalves hinged.... What is referred to as the visceral mass, mantle and foot away through their to... Flows through their mantle cavity 66 mya of every cephalopod is large neuron called giant! White diagram of them and close when needed, but the name stuck gases and exchange them between two. As she spawns in diameter, it is possible that early ammonoids in... Know of ) in January 2017, the international trade of nautilus shells had be... The name stuck bivalves are any creature with a soft body that lives between hinged...

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