Area
The Atlantic coast of Europe from Norway to Mauritania, the archipelagos of Macaronesia, the Mediterranean, Aegean, Marmara, Black and Azov seas.
Features of morphology
The shell is cap-shaped with a sharp apex, slightly shifted towards the anterior edge, the base size is up to 35–40 mm and the height is up to 14 mm. Sculpture of frequent radial ribs of unequal height and frequent thin concentric growth lines. The edge of the shell is finely toothed. The color is yellowish-white with reddish-brown rays, the inner surface of the shell is porcelain-white, without a pattern.
Features of biology
They live in the surf zone on a rocky substrate at the water's edge. They attach to the substrate with the help of a strong muscular leg. They belong to a group of predominantly herbivorous mollusks (unicellular and multicellular algae, detritus), which use a special organ, the radula, to scrape off growth on rocks. At night, they make food migrations and return to their original habitat (homing). They are protandric hermaphrodites - when the sexes change, the gonad goes through first the male and then the female phase of development. Spawns in late autumn and winter. It has a lecithotrophic larva with short pelagic development.
Threats
Eating by brine, contamination of the lithocontour, preventing the settling of larvae.
Security measures
The last discovery of a sea limpet dates back to 2007. Given the rarity of the species and local distribution, special attention should be paid to the protection of its habitats.
Information sources
Milashevich, 1916; Key to the fauna of the Black and Azov Seas, 1972; Chukhchin, 1984; TsikhonLukanina, 1987; Zaitsev, 2008.
Compiled by: Revkov N.K. Photo: Revkov N.K.
Family Saucers - Patellidae- molluscs with a characteristic conical-shaped shell. They inhabit rocks, preferring areas periodically washed by the surf. Looking at the frozen shells, you might think that the saucers sit in one place all the time. But this is not so, it’s just that the period of their activity occurs at night. At this time, they venture on journeys of several tens of centimeters in length. At the end of the walk, the snail invariably returns to its old place and takes its previous position. The shape of the edges of the sink exactly follows the irregularities of the stone. During low tide, the animal presses tightly against the rock and retains water until the next tide. The limpets are perfectly adapted to the harsh living conditions in the surf zone. A thick shell protects them from attacks by predators and from waves, and a wide leg acts like a suction cup. Tearing a saucer from a stone is not an easy task for a predator
Sea limpets are similar in appearance, but are profoundly different anatomically from fisurellids. At the same time, they are very similar to other representatives of sea limpets, tecturids and lepetids. Snails of this group are characterized by a simplified, symmetrical shell, shaped like a cap or an upturned saucer. An important anatomical feature characteristic of limpets is the presence in these snails of not two, but only one atrium, which is associated with changes in the respiratory system. In representatives of the family of limpets, both gills are reduced, remaining only in the form of rudiments; instead, secondary gills develop on the lower surface of the mantle. The family of sea limpets includes a relatively small number of forms. Patellidae are widely distributed in various seas, and some species are also found in highly desalinated inland seas. Some types of sea limpets are edible.
Scientifically they are called patella, in simple terms they are called sea snails or limpets, and in Madeira, where these flat-shelled mollusks are considered a local delicacy, they are called lapas. In fact, sea limpets are found not only on a remote island in the Atlantic Ocean - no, they can be found in abundance both in the Black Sea and in Mediterranean seas, where they live on coastal cliffs. To tear a mollusk from the stone it is holding on to, it takes a lot of effort - the slightest touch, and limpet presses against the stone, so much so that it is almost impossible to tear it off without a knife. But what to do if there is no sea or a bay with sea limpets a stone’s throw from your home, and it’s not in sight?.. The answer is very simple - prepare mussels according to this recipe, which (unlike sea limpets) can also be bought frozen.
Sea saucers with garlic butter
First, it is advisable to clean the sea limpets (although in Madera, it seems, they do without this at all). Take small knife, pick up a clam with it and immerse the knife to the middle of the shell, then, turning the shell, run the knife along the entire radius to separate the clam from it. Underneath you will find a “bag” with unappetizing black and green contents: the bag must be thrown away, and the elastic mollusk must be returned to its shell.
Cut the butter into small cubes according to the number of shellfish, and chop the garlic and parsley very finely and mix thoroughly. Transfer the sea limpets to a baking dish, add a cube of butter to each, a pinch of parsley-garlic mixture and season with salt and black pepper. Preheat the oven grill to high and place the pan under the grill. Remove after a few minutes, just after the butter has melted and bubbled.
Serve limpets (or lapas, as the Portuguese call them) as a hot appetizer, with white wine and white bread for dipping.
In general, the locals told me that these shellfish can be eaten raw, simply by peeling and sprinkling with lemon juice. Looks like it's true.
The sea limpet is a typical inhabitant of the surf zone of the Far Eastern seas. It is found on coastal stones and cliffs, tightly adhering to their surface, usually in shallow recesses and crevices.The shell of a limpet consists of one valve, spirally curled to the right or left, and on its surface, also spiraling around, there are clearly visible growth lines. As a rule, their number does not exceed twenty, by which one can judge the probable age of the mollusk. The shape of the shell can be very diverse: slightly flattened, with the apex shifted to the side, or, conversely, a towering regular pyramid...
In general, this mollusk is characterized by a simplified symmetrical shell, shaped like a cap or a saucer turned upside down, which is why it got its name. True, it would be a stretch to call such a shell a saucer, well, if only it served in this capacity for some tiny sea bird, for example, a storm petrel. Despite its apparent fragility, the shell of the limpet is very strong and is able to withstand the constantly incoming stubborn waves, without fear of the strongest surf.
Of course, the shape of the limpet shell is quite primitive, and yet these mollusks attract attention precisely because of the simplicity of their house, which seems very charming and secluded. The persistent waves are unable to knock these shells off the coastal stones, sea water, as if angry at the rebellious inhabitants of the coastal strip, flows freely from their smooth conical walls, and the tops of the shells are sharpened, no matter what, they are always determined to grow. I just want to tear the sea saucer off the rock and look - what is inside it?
Whether the tide is approaching or the tide is going out, outwardly the saucers do not react in any way to what is happening and from the outside they look like creatures completely indifferent to everything, even lazy. This is their original habitat, where they live, firmly attached to the coastal rocks, it seems, from time immemorial. Cone-shaped shells with bluish-gray, beige and cream tops are pressed against the stones so tightly that it is impossible to squeeze a knife blade between them. Even when the rocky surface turns out to be rough and uneven, the edges of the shell also become uneven and jagged, following all the irregularities of the stone, which gives the mollusk the opportunity to press tightly.
When a mollusk is disturbed, it presses against the stone on which it sits with enormous force, and in order to overcome the suction force of this ordinary small shell, you need to drive a sharp iron object between the shell and the stone. Then, using it as a lever, you should try to separate the mollusk from the stone, which most often breaks it: the attached leg remains on the stone, and the shell with the mantle and entrails comes off. But if the mollusk sits with its shell raised so that its head and side parts of the body remain open, then a light blow is enough for the saucer to separate from its attachment site.
For a long time, it was considered unclear how the limpet is attached: whether it is glued by the secretion of special glands, or is held in place solely by the shell muscle. It is now known that at first, indeed, mucus is secreted from the many skin glands of the sole of the foot, which serves to fill small gaps between the sole and the stone, and only after that the concha muscle begins to act with all its force, the ring shape of which is only broken in front by a small notch, thanks to why it resembles a horseshoe. The muscle tenses with every wave of the surf, as well as during the entire low tide, while the mollusk is exposed to sunlight.
Previously, there was an erroneous belief that, due to its very strong attachment to the rock, the limpet supposedly never changes its place. However, it turned out that the mollusk still travels, albeit only at night. It is remarkable that, moving in a certain way always to the left, he eventually returns to the starting point of his path and strengthens himself in the old place in the same way as he sat there before. When moving, the mollusk is helped by a uniform deviation from a straight line and its orientation in the vast sea space is limited to just a meter!
The limpet is very attached to its place of residence. It turns out that only if the place where the mollusk lives has undergone fundamental changes during his absence, he decides to search for something new and in no case settles anywhere. When choosing a more convenient place, the mollusk is guided by the need for air sufficiently saturated with water vapor, and therefore prefers crevices in stones, especially their shady side. But what forces the sea limpet to travel, and even at night?
The nocturnal wanderings of the sea limpet serve primarily to satisfy hunger, and doing this at night is less safe. During its movement, the mollusk eats the surface of the rock, and the gnawed strip reveals its path, because all the time while the animal is crawling, its radula, which are thick, strong blades - an excellent scraping tool, is constantly in action. The mollusk feeds on various microorganisms that grow on rocks, and along the way, small plants such as ulva and fucus, but it does not look for them on purpose, eating mainly everything that it can shave off the surface of the stone with its radula along the way. Its strong teeth fully correspond to its purpose in the surf rocky zone, but this work, however, leads to extremely rapid wear of the tool, and when it is completely worn out, the mollusk dies from the inability to feed, after which its shell falls off, replenishing the empty shell rock at the surf strip, where it is imperceptibly ground into the sand by the waves.
But along the banks of the Japanese and Sea of Okhotsk There are so many limpets, and scientists have discovered at least 11 species of them here, that there is no need to worry: this mollusk will never run out. The largest of the sea limpets, the pale acmea, is found off Southern Sakhalin and the Southern Kuril Islands. Its strong, thick-walled, almost snow-white shell reaches 6-8 centimeters in length.
When such a shell, already without a mollusk and carefully licked by the sea, falls into your hands, you want to weigh it in your palm, run your finger along the smooth inner walls, ultimately not knowing what to do with it next? But you are not able to get rid of the shell right away and again begin to turn it over in your hands, examining and admiring it until you take it as a souvenir and then give it to some person you know well. I remember that I collected a great many of these saucers, because they were all attractive with their shape or color, and I stopped in my hobby only when I realized that the shells began to repeat each other. Many of them now lie in my closet, behind glass, and sometimes for some reason I touch their cool sides or even pick them up, returning them with regret. You won’t believe it, the limpets are still quietly emitting the light rumble of the rolling surf, and it seems to me that they are not at all worried that I deprived them of their beloved Sakhalin coast...
And I again remember the rugged island shores with deep creeks and black rocks, sand spits and underwater ridges, densely covered with sea limpets... Small conical shells made of fragile limestone always for some reason made me timidly want to smile. Maybe because they steadfastly resist the persistent surf, and also resemble the so-called “Chinese hats” made of straw, with the help of which Chinese and Japanese fishermen usually save themselves from the sun while working, and shellfish from numerous enemies. Thanks to the acmeas, tightly clinging to the wet stones, hardworking Asian residents appear in your memory, and when you see the Japanese or Chinese in straw hats, the graceful shells of sea limpets that live near the sea appear before your eyes. This is probably due to the surprisingly similar forms and the fragile charm of the lines, containing the sensitive laconicism of ordinary natural truth, which does not seek to embellish itself, but only wants to defend itself. In a word, there is something very touching in the sea limpets that is impossible to explain.
Some acmea shells are so expressive in their color that at first you will even mistake them for sea snails or littorinas: in the very middle, at the top, they have bluish tint spots, bordered by delicate greenery, reminiscent of algae thrown out after a storm. The surprisingly discreet and gentle combination of these colors even seems to enlarge the shell, making it more alive. The mollusk itself is not visible, but its house is distinguished by its elegance, and therefore the owner of this house is also perceived as graceful and sweet. A small, pea-sized mollusk, judging by its habitat, lives in it quite reliably and joyfully, like a magic pearl.
The gentle name of the shell is acmea, and its neat appearance, designed by nature, evokes an equally touching phrase - cameo... A stone decoration with artistic carvings and a convex image, most often it is onyx or agate... And sometimes, oddly enough, an elegant cameo brings back memories about the sea, while at the sight of the acmea itself, sensitively attached to a wet stone, one is reminded of an exquisite jewel, without which it is impossible to imagine a reverent attitude towards any beauty. The beauty of the sea carries many priceless surprises, and all of them make up its mysterious, enchanting bliss. The sea itself is an unsurpassed blue pearl framed by red, black and grayish-green coastal granite.
More often, however, acmea remains discreet, completely unnoticeable, well, if only you pay attention to it at low tide, when shells and stones that have not yet dried out shine with their true colors. Having in its very middle, at the top, a bluish-smoky coating, which also appears as a radiant lake surrounded by dark rocky shores, acmea, in miniature, resembles the sea that gave birth to it. But then a light breeze from a land unknown to her will fly in, dry the shell, and it will shut down again, becoming completely inconspicuous. Who will pay attention to this discreet beauty now?
I always liked to note these inconspicuous manifestations for myself sea life, look at them and remember them. This is how I once became acquainted with acmea, at first not knowing what this neat, graceful shell is called, and when I heard its unusual name, even for the sea, I rejoiced even more with the overwhelming joy of being near the sea world. What is not hidden in it, and here you go, such an inconspicuous and touching given - acmeia! Something airy, but also strong, inseparable from the gloomy stone shores, in a word, subtle and strict. Akmeya... Enchanting underwater dreams, the dream of an unknown mollusk lulled by sea waves, its unwavering commitment to unbending rocks...
Although the acmea shell is fragile and elegant, it is not easy to separate it from these stubborn, gloomy and wave-rolled boulders. Acmea itself resembles a sea pebble nestled comfortably in some crevice, and I never had the desire to deprive the shell of its habitat. Only once did I try to separate with an underwater knife one of the shells with a blue tip that I liked, but I almost broke the tip of the blade while I tore off several mollusks, a good half of which I simply crumbled: the shells were tightly attached to the stones, and it was better to pick up those that were already detached, empty, than to disturb the living. True, the old limestone houses already looked unattractive; they were mostly of a dirty gray color, and had only been broken in for for a long time the sea became snow-white, and the shape of the shells still remained conical, sublime, as if rushing, in spite of everything, towards something unattainable and beautiful.
In general, while at sea I constantly had the feeling that it knew everything about me, knew that I would never forget about it, and someday I would write about its currents, fogs and winds, animals living in the depths and mysterious thickets of algae, I will mention , of course, about stones, especially about shells. The shells and stones felt me in some unimaginable way, did everything so that I would discover them at some appropriate moment, and even if I didn’t take them with me, I would definitely examine them by picking them up and then carefully returning them to their place. Everything that surrounded me in the sea and next to it was alive, it radiated its invisible energy, which I sensed with an inexplicable instinct, and from this mutual understanding with your native element, life became even more joyful.
Teeth a common type of mollusk limpet (Patella vulgata) stronger than Kevlar and stronger than spider silk, scientists report in the February 18 issue of The Royal Society Journal.
Limiters are hardy little molluscs that are ubiquitous in our planet's oceans. Their conical shells protect the stalk, which they use to attach themselves to underwater rocks with incredible strength. The limpets feed on algae by releasing a long tongue lined with hundreds of sharp teeth that scrape food particles off rocks.
A research team from the University of Southampton, England, led by mechanical engineering professor Asa Barber, examined microscopic fragments of the mollusc's teeth. Each curved tooth is about 1 millimeter long and is about 100 times thinner than a human hair.
According to Barber, the secret to the strength of these teeth lies in the size of the fiber structures that form it. As long as the dimensions of these fibers are below a certain critical length, their strength remains unchanged, even if their material contains defects. They themselves are a biological composite of goethite (mineral iron oxide) and chitin, which plays the role of natural plastic.
As a result of this combination, teeth made of this material can withstand a load equivalent to 1,500 kilograms suspended on a spaghetti-thin thread.
The next task for scientists will be to reproduce the mechanism by which limpets create these unique materials. And although spider silk has proven to be an incredibly difficult object to imitate in artificial conditions, researchers believe that limpet tooth fibers can be 3D printed.
Spider silk is one of the most durable natural materials. Its fibers have a specific strength five times higher than the best varieties steel, and at the same time they can stretch freely. The strongest known silk is produced by Darwin's tree spiders, which are found in Madagascar - their silk is 10 times stronger than Kevlar. To put things into perspective, the mineral teeth of the limpet are stronger than this silk by about 10 percent.
