The largest mollusk shell in the world. Giant tridacna - the largest mollusk
Mytilasters, etc. They live at all latitudes and at different depths (from the very coast to the abyssal), in particular, in all the seas of Russia. The most important commercial and cultivated species belong to this family - the edible Mediterranean mussel, etc.
On Orinoco A, where a powerful stream of methane emerges from the sediment, boomerangs sit, only slightly immersed in the soil - erupted mud volcanoes silt with lime nodules. On Orinoco B - inactive, with a weak methane flow, but a high content of hydrogen sulfide in the sediment - the mollusks burrow deeply into the silt, with the front end obliquely downward, so that only the back third of the shell protrudes out. Like all mussels, the boomerang is attached to the substrate by threads emerging from its leg. organic matter, but since there are no stones or rocks there, they have to cling to small nodules or shells of their own fellow creatures. When young, boomerangs have the usual oval, non-curved shell for mussels, the length of which is twice the height, but as they grow, the shell bends, the ratio of its length to height increases to 3.5, and the mollusk sinks deeper and deeper into the silt. Old clams usually don't attach to anything. On Orinoco A, along with the boomerang, there lives another, as yet undescribed, species Bathymodiolus, which feeds only on methane.
Why boomerang batymodiols grow so large is clear: the larger the mollusk, the longer its gills (their length is 75-80% of the length of the shell) and, therefore, the more bacteria they contain; this, by the way, only applies to the gills: other internal organs lag behind in growth. But for what reason are boomerangs so large? The authors offer three explanations. First: because the shell is not round, but elongated. This is unlikely to be the case - among mytilids there are many species with an elongated shell (for example, shallow-water Modiolas), but especially large sizes they don't stand out. The second explanation is that there is a lot of food on the accretionary prism for shellfish. It’s also doubtful - after all, there is no more of it there than in shallow waters temperate latitudes, where waves bring a lot of phytoplankton. Entire fields of mussels (mussel banks) develop there - the biomass is huge, and the size of the mollusks is normal. And third: they live a very long time. This is more like the truth. Our Far Eastern Gray mussel, with a length of 20 cm, reaches a century of age! True, the growth rate of the Gray mussel is low, as a result of which it is unsuitable for artificial breeding. Galapagos Rift Batimodiola (B.thermophilus) grows rapidly, 1 cm per year, and reaches a size of 18.5 cm at about 19 years of age. But it’s hot there at the bottom, and in the Barbados Prism the temperature at the bottom is low, normal for two-kilometer depths. But hot seeps exist for a few decades, and the age of the Barbados cold seeps is estimated at 7-20 thousand years. So mollusks can easily live there for hundreds of years. But how much has not yet been established. It is not even known when boomerangs reach maturity. But it is possible that this is not only the largest, but also the longest-lived mussel in the world.
Cosel R. von, O l u K. // Compt.Rend. Acad. Sci. Paris. Sci. de la Vie. 1998. T.321. P.655-663.
A true kingdom of diversity bivalves. The largest representative among them is tridacna.
(a 1.15 m raised shell was recorded weighing 333 kg) but the body itself weighs less than 30 kg. Unofficial records for the species indicate a height of 2 m and a weight of more than 500 kg.
Tridacna gigas grows over a meter long and weighs over 200 kg
Tridacna giant. Red sea. Dangerous shellfish.
Another species lives in the Red Sea, a little more modest in size, but just as beautiful - Tridacna elongata (oblong tr.), usually 50-60 cm.
Tridacna oblongata. Red sea.
Tridacna elongata. Red sea.
Culture of cohabiting microalgae under the influence of sunlight produces carbohydrates, giving some of it to the needs of the owner, receiving protection in return. Shallow water spaces of coral plateaus, illuminated sun rays, create ideal conditions for the prosperity of these huge beauties.
The main method of obtaining food is filtration.
Tridacna continuously circulates water, straining out plankton
The mantle of the open shell valves is sensitive to water fluctuations; the mollusk instantly closes with any movement near it, especially when touched. Because of this feature, tridacna received the names "killer clam" And "death trap" .
Tridacna bivalve mollusk. Red sea.
TO dangerous representatives inhabitants of the Red Sea, the mollusk is classified conditionally.
Even if you walk carelessly in shallow water during low tide, it is possible to fall into such a mousetrap. Of course, such a hypothetical possibility of stepping on a brightly colored trap is greatly exaggerated, but there are facts of examples of stupid carelessness.
Cases of death of divers caught in the trap of slammed shutters are not uncommon.
The knife is practically useless because... the length of the blade does not allow it to reach the contracting muscles of the giants. There are descriptions real cases when, in order to save themselves, divers were forced to cut off part of their arm or foot. At the same time, there are descriptions of the hunt of divers collecting pearls, who manage to insert a hand with a knife into the cavity of the shell with a lightning-fast movement and cut the adductor (tightening muscle) until the valves are completely closed. By the way, the largest pearls are grown by Tridacna.
Members of the family Tridacnidae are hermaphrodites with cross-fertilization capabilities.
The larvae swim as plankton for up to 2 weeks. At the end of the plankton phase, they sink to the bottom in search of a suitable substrate and are permanently glued using byssal threads.
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Unlike most bivalves, tridacna is attached open edges shell up, so anatomically her body is rotated 180° inside the shell. The leg is small, and so is the mouth. The mantle is fused along its entire length (except for the areas of the two siphonal openings and the exit of the byssal gland), and often does not fit into the shell. Thick valves with wavy edges, stretched triangular in shape, have pronounced convex radially diverging ribs. At the base of the shell between the valves there is a gap for the byssal gland.
Underrated gastropods
Snails deserve much more public attention. Although they are, as a rule, extremely slow, they should by no means be called boring creatures. There are luminous and transparent snails, some gastropods are equipped with heavy shells or unusually beautiful shells. There are even snails that can kill a person. We invite you to get acquainted with the most interesting mollusks in the world, which prove that patience is truly a virtue.
Lantern snail Hinea brasiliana
This little-studied sea snail offers the most amazing light show in nature. Thanks to the ability of bioluminescence, this creature glows bright green in moments of concern or threat. Researchers believe this trick helps the snail frighten or confuse predators.
Giant Achatina
These large and hungry gastropods are the most... big snails on the ground. They grow up to 20 centimeters in length and up to 10 centimeters in diameter, approximately corresponding in size to the palm of an adult. In addition, these snails are very voracious; their diet includes at least 500 species of plants. If there are no vegetables or fruits nearby, these creatures are capable of swallowing anything, including paint and plaster on the walls of houses. It's good that they are vegetarians.
Rainbow snails Liguus virgineus
These most colorful gastropods in the world, found on the island of Haiti, are often called rainbow snails. Looking at them, you might think that they were specially painted, but in fact, these shells were given such a pattern by Mother Nature.
Pteropod
They don't look like regular snails but these are elegant sea creatures are among the most numerous gastropods. As a rule, snails use their legs to move on the ground, and pteropods use a wing-like appendage to move through the ocean waters. A number of species have even gotten rid of their shells in order to swim as efficiently as possible.
Tylomelania
This cute mollusk, which looks like a cross between a snail, a mango and an elephant, revives images of failed genetic experiments in the brain. This creature needs a special “trunk” to sift sand in search of food.
Iron snail Crysomallon squamiferum
The iron snail, discovered in 1999 in the central Indian Ocean at a depth of 3 kilometers, may be the most heavily equipped mollusk in the world. Its shell looks like ringed-plate armor, and this impression is not very far from reality. Thus, the shell of this creature contains metals and sulfides from hydrothermal sources. The outer layer of the shell is coated with iron sulfide, creating real metal plates.
Melting snail
The leg of a South American flat-bodied snail from the genus Megalobulimus can stretch greatly, becoming so thin that the creature appears as if it is melting. In some species this analogy is incredibly accurate.
Geographic cone
But this snail should be handled with care, as it is the most poisonous shellfish of all existing on the planet. The cone venom is a complex combination of hundreds of toxins and is fired using a harpoon-like tooth located in a flexible proboscis. Although this snail, like its other brethren, moves slowly, its “spitting” is almost the fastest in the animal world, because this poisonous harpoon is capable of reaching 640 kilometers per hour.
Yantina brittle
Beautiful purple shells are just some of the features that make these snails unique special interest. Janthina janthina collects air bubbles with the help of their mucus and travels long distances across the oceans on such a bubble raft.
Opisthostoma snails
Opisthostoma is a genus of tiny land snails, which boast perhaps the most unusual shells in the mollusk world. Many species of these creatures have shells that twist, creating complex and intricate structures, but the worm snail Opisthostoma vermiculum has a unique structure shells. It has as many as four axes of curl, which is more than any known gastropod.
Croatian cave snail
The eerie creatures, recently discovered in Croatia in one of the world's deepest cave systems, Velebit, are particularly notable for being almost completely transparent. Gastropods that are visible through are real cave dwellers who have lost their sight.
Hairy snail
The shell of the most sinister species in the gastropod world belongs to a hairy snail - spike-like structures protrude from it. But despite its gluttony, this creature’s menu includes mainly vegetarian dishes.
Most people associate shellfish with oysters and other seafood that are used as food. But the mollusk that we will talk about today will not fit on any plate, because its weight can reach 300 kilograms. Today we will talk about amazing creature- the largest mollusk in the world.
Giant tridacna really huge, and its size simply cannot be comprehended. With a shell length of 1.2-2 meters, its weight is on average 200 kilograms, although heavier specimens are also found. The largest of all discovered representatives of the species was found near the Japanese archipelago and weighed 340 kilograms. According to this indicator, he was even included in the Guinness Book of Records.
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The giant tridacna (lat. Tridacna gigas) belongs to the class of bivalve mollusks and is found in warm waters Indian and Pacific Oceans. She is one of the inhabitants of coral reefs. In addition to its enormous size, this mollusk also has a very unusual coloring- from gray-green to blue-violet shades. The thing is that in the folds of its mantle live the simplest organisms - single-celled algae. These algae, in addition to serving as food for the tridacna, also supply it with nutrients, which they themselves produce.
These mollusks are long-livers, whose age reaches 100-200 years. Tridacnids are hermaphrodites and reproduce to form thousands of larvae (veligers). During the first days of life, the larvae travel together with the rest of the plankton, obeying sea currents, and then the young tridacni settle forever at the bottom and begin to grow. On average, the size of their shell increases by 6-10 centimeters annually. Over the years of growth in one place, the tridacna becomes covered with a layer of silt and algae, and a couple of crabs often settle inside.
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Among pearl collectors, a giant tridacna for a long time was considered dangerous creature, capable of grabbing a person’s hand or even swallowing him whole. In fact, these are peace-loving creatures that feed on plankton, filtering ocean waters. Although these fears are not without foundation: there are known cases of the shell closing, when a person had to free his trapped hand using a knife. But this is only a manifestation of the animal’s reflex characteristics, and not a sign of aggression.
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Although the giant tridacna is capable of producing pearls, they are mined mainly for making souvenirs for tourists, since they are not suitable for jewelry. The size of the tridacna's pearls is impressive, just like the tridacna itself. The largest tridacna pearl known to date weighs 6.37 kilograms and measures 15 by 28 centimeters.
Today, two organisms are fighting for the title of the largest mollusk on earth, which amaze the imagination with just one of their appearance, despite the fact that the situation is not only in truly gigantic proportions. And first of all, we will talk about the giant tridacna, which claims to be the largest mollusk in the world.
Thus, one of the largest mollusks in modern world is a huge double-leaf shell, as if it came out of the painting of the great Botticelli “The Birth of Venus”. Today, this huge tridacna, belonging to the order of cordates, lives in the waters of the Pacific and Indian Oceans, often reaching a length of as much as 120 centimeters, which is truly impressive. Naturally, such dimensions could not but affect the mass of the mollusk, which can easily exceed 200 kilograms, as a result of which only a professional athlete can lift it. The life expectancy of the giant tridacna is also surprising, because it most often exceeds centuries, which, in principle, is characteristic of many mollusks. Because of my unusual shape, vaguely reminiscent of the outlines of a military uniform hat, the shell received a second name - a giant cocked hat. As for the lifestyle of this “baby”, she, like other shells, feeds mainly unicellular algae and plankton, passing through their gills great amount water along with sand and debris, which can linger in the sash, becoming overgrown with the most delicate mother-of-pearl.
Yes, yes, the giant tridacna also produces pearls, and huge ones, however, they have no value in jewelry. Today, the largest pearl in the world is the pearl of Lao Tzu, which is included in the famous Guinness Book of Records thanks to its truly gigantic size(24*14*15 with a mass of almost 6.5 kilograms). As for the shell itself, its record size was recorded in 1956, when on one of Japanese islands A giant tridacna was pulled out to the surface of the water; its length reached 115 centimeters and its weight was 340 kilograms. Naturally, this record was immediately entered into the Guinness Book of Records and today this particular specimen is officially considered the most large clam in the world. But the second contender for this title has, to put it mildly, a less aesthetic appearance, because we're talking about about the famous penis fish, which is more often called a geoduck or an elephant trunk, although in appearance it looks exactly like the male genital organ.
The structure of this burrowing mollusk is truly unique, because with a relatively modest shell, the length of which rarely exceeds 20 centimeters, the trunk of this monster can reach as much as 100 centimeters in length. This feature is directly related to the main activity of the mollusk, which is accustomed to burrow deeper into the muddy bottom of sea reservoirs, thus protecting itself from predators and at the same time hunting for everything that can be swallowed. And it is precisely because of this that the longest burrowing mollusk in the world received the name guidak, which is translated from the Indian language as “deep-digging.” It is noteworthy that the largest specimen of a sea penis ever caught by a person weighed about one and a half kilograms and this figure became an absolute record for today. One more unique feature this bizarre mollusk became its longevity, because average duration his life span ranges from 146 to 160 years. Scientists themselves just shrug their shoulders at this, attributing the longevity of the geoduck to too slow a metabolism. It may be hard to believe, but the meat of this mollusk, or rather its siphon, despite all its toughness, is quite widely used in cooking. For example, it can be found in exotic American restaurants, although the main consumers of penis fish continue to be the Chinese and Japanese markets.
In addition, residents are very fond of elephant trunks. South Korea, despite the fact that they prefer to eat it in the form of sashimi, that is, completely raw. So, for example, in one of latest issues The popular travel show “Heads and Tails” aired a story in which the presenter had to try this sea reptile.