Snails, or gastropods, constitute the most species-rich class of soft-bodied animals. There are about 90,000 species in this class. They populated both the coastal zone of the oceans and seas, as well as significant depths and the open sea; they settled in fresh waters and adapted to life on land, penetrating even rocky deserts, the subalpine mountain belt, and caves. Some modern bands freshwater gastropods went through a very complex evolutionary path: they came out of sea reservoirs onto land, and in connection with this acquired new type breathing, and then again went to “permanent residence” in fresh waters, retaining there, however, this type of breathing acquired on land. One of characteristic features Gastropods are distinguished by the presence of a solid shell, not divided into valves or plates and covering the back of the animal; it would be more correct to say that the shell covers here the so-called internal sac, i.e., a sac-like protrusion on the back, inside which there is a number of organs. Another typical characteristic of gastropods is that most of them have lost bilateral symmetry. The intestine of all modern gastropods forms a loop-shaped bend, and therefore the anus lies above the head or to the side of it, on the right side of the body. Most gastropods the shell is twisted into a spiral, with the revolutions of the spiral most often lying in different planes. Such a spiral is called a turbospiral. The whorls of the shell form a whorl. In addition, a distinction is made between the apex and the mouth - the hole from which the head and leg of the mollusk protrude. Accordingly, with the spiral twist of the shell, the internal sac is spirally twisted. In the vast majority of cases, the twist is observed in a clockwise direction, that is, to the right, when looking at the shell from its top; in more rare cases, the shell and visceral sac are twisted counterclockwise, i.e. to the left. Based on the direction of twisting of the shell, right-handed (dexiotropic) and left-handed (leotropic) shells are distinguished, and sometimes individuals of the same species can have both right- and left-handed shells. Shells of various snails appearance extremely diverse, which is determined by the number and shape of the spiral’s revolutions, and how steep or gentle its revolutions are. Sometimes the whorls of the shell spiral, tightly adjacent to each other, grow together with their internal parts, forming a solid column (columella), sometimes they lag behind one another, due to which, instead of a solid column, an umbilical canal is formed along the axis of the shell, which opens at the last whorl of the shell with a hole called the umbilicus. Finally, in a number of cases we see in snails a seemingly simpler shell in the shape of a cap or saucer, but, as the history of development shows, such shells in modern snails are the result of a simplification of the initially spirally twisted shell. The violation of bilateral symmetry characteristic of most gastropods, i.e., the asymmetry of the organs of the visceral sac and mantle cavity (one gill, one atrium, one kidney), is caused by the turbospiral shape of the shell. With this shape of the shell, with the helix directed to the side, and with the fact that the bulk of the liver is located in the last turns of the helix, the center of gravity of the shell is shifted away from the midline of the body. Due to this, one of the sides of the open (estuarine) whorl of the shell is closer to the body than the other side, raised above it. All this resembles a hat worn on one side. But this position of the shell narrows the space of the mantle cavity on one side, which leads to the reduction of one of the gills and the associated atrium and, naturally, the kidney. The correctness of this explanation for the occurrence of asymmetry in gastropods is confirmed by the fact that all stages of its development can be observed in modern primitive representatives. In some gastropods with a cap-shaped shell, bilateral symmetry of the entire complex of pallial organs is still preserved; in others, one or both ctenidia and the atrium can be seen to be reduced.
The shell of gastropods is covered with a thin layer of organic matter, which makes up its outer layer - periostracum. The latter sometimes forms bristle-like processes, making the shell appear shaggy from the outside. The part of the shell covered by the periostracum is composed of thin calcareous plates, which together make up the so-called porcelain layer, in which, in turn, up to three layers of calcareous plates can be distinguished. In some (a relatively small number) snails, the inner surface of the shell is lined with a shiny mother-of-pearl layer. Intraspecific shell variability of many gastropod species is very wide. This breadth of its variability shows the importance of the shell in ensuring the adaptability of individuals of the species to living in places with different combinations of factors environment. The researcher of Black Sea mollusks V.D. Chukhchin showed the existence of differences in the shape of the shell and in its thickness between males and females of the same species.
Moving on to the consideration of the soft parts of the body of snails, first of all, it should be noted that they have a more or less separate head, bearing a mouth, eyes and tentacles, and on the abdominal side - a massive muscular leg with a wide lower surface, called the sole. The characteristic method of movement for most snails is slow sliding along the substrate on the sole of the foot, and the movement itself is carried out thanks to waves of contraction running along the sole of the foot from back to front. The abundant mucus secreted by the skin softens friction and facilitates sliding on a hard substrate. In some snails, due to their transition to a different type of movement, both the function and structure of the leg change. In many snails, the back of the leg bears a special horny or calcified cap on the upper surface, and when the snail hides in the shell, the cap closes the mouth. The shell is connected to the body with the help of a powerful muscle, the contraction of which pulls the snail inside the shell.
Directly under the shell, covering the internal sac, there is a mantle, the anterior thickened edge of which hangs freely over the body of the animal and covers the mantle cavity formed under it, into which the anal, excretory and genital openings open; holes. The mantle cavity also contains respiratory organs - most often one feathery gill, or cteninidia (a relatively small number of snails have two gills); in snails belonging to the pulmonate subclass, the gills are lost, and the roof of the mantle cavity functions as a lung. The free edge of the mantle in some snails can extend into a more or less long tube - a siphon, located in the siphonal outgrowth of the shell. In other cases, the free edge of the mantle may be folded over the edge of the shell, so that the mantle, protruding from under the shell, partially or completely covers it from above. In the latter case, the shell becomes internal, usually undergoing reduction to one degree or another. The snails' mouth leads into a voluminous oral cavity, which contains a paired or unpaired jaw and an organ typical of most mollusks - the grater, or radula. The ducts of paired salivary glands open into the oral cavity, and in some snails, ducts of other glands, such as poisonous or acid-secreting ones, open. A thin esophagus extends from the oral cavity, in some snails it expands into a voluminous crop, and the latter passes into the stomach, into which the digestive gland (“liver”) opens. The intestine begins from the stomach, which is shorter in carnivorous gastropods and longer in herbivores. The intestine opens outwards anus inside the mantle cavity.
The circulatory system of snails is not closed: the heart consists of one ventricle and one atrium (a few forms have two atria). The atrium collects oxidized blood from the gill or lung, from where it is distilled into the ventricle, and then distributed throughout the body through the branching cephalic and splanchnic aortas. The heart of the snail lies inside the pericardial cavity. The excretory organs, the kidneys, communicate with this cavity, and in rare cases they are paired. The nervous system of snails consists of 5 pairs of nerve ganglia, or ganglia: cerebral, leg, or pedal, pleural, visceral and parietal. Ganglia are connected by nerve cords: those of the same name are called commissures, those of different names are called connectives. Due to the twisting of the visceral sac, in snails belonging to the prosobranch subclass, as well as in some of the lowest representatives of the other two subclasses (opisthobranch and pulmonate), a characteristic crossing of connectives is formed between the pleural and visceral ganglia. The higher opisthobranchs and pulmonates do not have this decussation. The convergence of various ganglia and the corresponding shortening of the connectives connecting them is very pronounced in many snails. In this case, all the ganglia located under the pharynx, including the pedal ganglia, form a compact group.
Of the sense organs, in addition to the eyes on the front pair of tentacles of the head and a pair of head tentacles, which have the significance of organs of touch, snails have developed balance organs - a pair of statocysts, which are innervated from the cerebral ganglia, although they lie in close proximity to the pedal ganglia. Statocysts are closed vesicles, the walls of which are lined with ciliated and sensory cells, and the cavity contains a liquid in which one large or many small grains of calcium carbonate float. The pressure that calcium carbonate grains exert on one or another section of the vesicle wall at different positions of the cochlea allows it to orient itself in space. Snails also have a chemical sense organ - the osphradium, which lies at the base of the gill and serves to sample water entering the mantle cavity. The second pair of head tentacles in land snails is the olfactory organ. In addition, the skin of snails is rich in sensitive cells. Gastropods have very well developed chemoreception. Specialized nerve cells of the tentacles, areas of skin near the mouth and osphradia provide remote recognition of food, return to a previously chosen place, and a sense of the proximity of predators, for example starfish or brittle stars, by their smell.
The reproductive system of representatives of different subclasses of gastropods has a different structure. Among snails there are both dioecious and hermaphroditic forms. In the latter, the structure of the reproductive apparatus is the most complex. Fertilization in most gastropods is internal. Gastropods have different spawning methods. The most poorly organized forms release eggs and sperm directly into the water, where fertilization occurs. Some species envelop eggs with mucus, forming cords, cocoons, and slimy shapeless masses. Such aggregations of eggs are most often attached by mollusks to a substrate - algae, empty shells and to the bodies of other aquatic animals, and buried in the ground of reservoirs. Terrestrial gastropods bury eggs in moist soil or attach them to the stems and roots of plants. The development of gastropods either occurs through the larval stage, which will be discussed later, or it is direct, i.e., a small mollusk emerges from the egg shells with an incomplete number of shell revolutions and an undeveloped reproductive system. But in all groups of gastropods, along with direct development, viviparity can also be found, when eggs develop in special parts of the mother’s reproductive system. In other cases of direct development, eggs are incubated under the protection of a shell or mantle until the young hatch.
Let us now return to cases of development of gastropods with the larval stage. In some, very few modern marine gastropods, a larva emerges from the egg - a trochophore, very similar to a larva annelids. Trochophores are characteristic of the most simply organized gastropods (Patella, Gibbula). The free-swimming trochophores soon develop into the next larval stage, the veliger. In some gastropods, the trochophore stage takes place inside the egg membranes and the veliger larva or, as it is called, “sailfish,” emerges from the egg. The larva received this name for its movement with the help of highly developed sail-like blades of the mantle, the edges of which are covered with cilia. In different species of gastropods, veligers spend different times in the water column and, as a result, are carried to different distances from the spawning site. The settling of larvae to the bottom is facilitated by chemical substances, secreted by other organisms with which gastropods usually live - cyanobacteria, corals, sponges, algae. These chemical signals perfectly demonstrate the complex relationships between different species that form part of biocenotic relationships. After the larva settles to the bottom, its metamorphosis occurs, i.e., the larva transforms into an adult mollusk. This is accomplished by shedding the larval skin with cilia, and in other cases by shedding other parts of the larva’s body. By this time, the body of an adult mollusk has already formed under the larval covers. There is evidence that metamorphosis is stimulated by chemical substances secreted by those organisms that are most characteristic in the usual habitats of this type of mollusk.
Many marine species gastropods are eaten by fish - herring, sardines, mackerel. As Lebur points out, these fish eat especially heavily the planktonic larvae of gastropods. Other fish, such as gobies, destroy adult benthic gastropods. Birds are also not averse to feasting on gastropods; various waders that live on sea beaches and nearby are especially active. fresh water bodies. Terrestrial gastropods are eaten by thrushes and some other birds, and among mammals - hedgehogs and moles, as well as reptiles. Gastropods are often attacked by predatory beetles, tahini flies, and fireflies. Flies and wasps use the empty shells of terrestrial mollusks to lay eggs. Sponges, bryozoans, sea acorns, hydroid polyps and other animals often use the shells of marine gastropods as a substrate on which their larvae settle. To date, there are different views on the taxonomy of the class of gastropods. The most natural groups of gastropods can be considered the following: subclass Prosobranchia, subclass Opisthobrauchia, subclass Pulmonata.
It is hardly possible to list all the prosobranchs that are eaten by the population of the coastal regions of the countries of Southeast Asia, Africa, South America. Many species, such as littorina, buccinum, patella, etc., are still in great demand. The colorful, elegant shells of snails are used in the form of jewelry - beads, pendants. Cameos are cut out of them, and. colored hypostracum, dark brown in Cassis cameo, yellow in C. rufa, pink-red in Strombus gigas, stands out very impressively against the white background of the ostracum. Finally, Tchochus shells are used as raw materials for button production. All this, unfortunately, is associated with the destruction of a significant number of mollusks and leads to the destruction of natural communities.
SUBCLASS OSPISTHOBRANCHIA Opisthobranchia are significantly inferior to prosobranch mollusks in the variety of forms, but still constitute a rather species-rich group of gastropods. The most primitive representatives of this subclass retained some similarities with prosobranchs. This similarity is expressed not only in purely external signs of body shape or in the presence of a spirally twisted shell with a more or less elevated curl, but also in the anatomical features of the structure nervous system, gill apparatus and other signs. However, most of the opisthobranch species in the process of evolution deviated quite far from the original ancestral forms, which, as can be assumed, had typical features of prosobranchs. The mantle cavity in opisthobranchs, if present, is relatively small and located on the right side of the body. The atrium lies behind the ventricle, and the ctenidium lies behind the heart (hence the name “postobranchs”). In many opisthobranchs, the shell is overgrown with a mantle and undergoes reduction to one degree or another. In some forms it is reduced to a small plate of irregular shape lying under the mantle, in others it disappears completely. Only a very few, more primitive species have an operculum that closes the mouth. It is interesting to note that among shelled opisthobranchs there is a very large percentage of species with a left-curved (leotropic) shell. The leg of many representatives of the subclass changes greatly. There are a number of forms in which the leg is extremely poorly developed, and in some it is completely reduced. In others, on the contrary, the sides of the legs grow into wide wing-shaped blades, the so-called parapodia, which are used for swimming. The structure of the respiratory organs also undergoes drastic changes. Most often, in the various pestles of the body of opisthobranchs there are skin outgrowths - secondary gills that develop to replace the lost true ctenidia. Secondary gills are usually located symmetrically either around the anus, or on the sides of the back, or on the underside of a special thickening of the mantle on the back of the animal. Opisthobranchs may have a common characteristic feature in the external shape of their body - a certain tendency to return to bilateral symmetry. This trait is manifested not only in pelagic forms, but also in forms that live on the seabed and move by crawling, like other mollusks. The anus of some opisthobranchs is located on the midline of the back. In some species the body is strongly elongated in length and laterally compressed, while in others, on the contrary, it is flattened in the dorso-ventral direction and acquires a general external resemblance to the body shape of the flatworms turbellaria. A certain return to bilateral symmetry is also manifested in the structure of the nervous system: if in primitive representatives of the subclass, closer to prosobranchs, we still find the crossing of pleurovisceral nerve trunks typical of the latter, then in other opisthobranchs this feature is barely noticeable.
Among the sensory organs typical of mollusks, as a rule, there are balance organs (statocysts); The osphradium associated with the gill is present in representatives of the order Angiobranchia, to which the more primitive forms of the subclass belong. Characteristic of opisthobranchs are areas of skin on the head on the sides of the mouth with accumulations of sensitive cells, which apparently serve as organs of smell or taste. In a number of forms, the same functions are performed by sensitive cells located on the posterior pair of head tentacles (rhinophores). As organs of touch, some opisthobranchs develop tentacle-like appendages on the sides of the mouth. As for the eyes, although in most opisthobranchs they are developed, they are of secondary importance in these mollusks and are usually covered with skin. The heart of opisthobranchs consists of one ventricle and one atrium and lies in the pericardium. Only in one genus (Rodope) the heart is reduced. The unpaired kidney connects to the pericardial cavity, and its external outlet opens on the right side of the body or at the base of the gill. The gonads are hermaphrodite, and the reproductive apparatus is more complex than in prosobranchs. Sexual maturity usually occurs during the second year of life, and after reproduction, the opisthobranchs quickly die. Among opisthobranchs we find both herbivorous forms and predators. Most animals have a well-developed radula, and some, in addition, have a mouth armed with a ring of spines or numerous hooks. Available salivary glands and the digestive gland, the so-called liver, which in some opisthobranchs is divided into many separate lobules. This organ serves to digest and assimilate food, particles of which are captured by cells (intracellular digestion). In some opisthobranchs, the muscular stomach has hard calcified plates on the inner surface, which serve for better grinding of food. Most opisthobranchs live on the seabed, on sandy or muddy ground, many close to the water's edge, so that at low tide they can easily be found among algae thickets or accumulations of hydroids. Species that usually stay at the bottom can, with the help of developed skin folds, rise above the ground and swim short distances. Opisthobranchs, part of the order pteropods, are typical planktonic animals. Representatives of the subclass of opisthobranchs are widely distributed in the seas, with most species living in warm seas and seas temperate zone, but many of them are also found in cold zones, and several species have adapted to life in the mouths of rivers (the islands of Palau and Flores in Micronesia).
SUBCLASS PULMONARY (PULMONATA) Pulmonary snails represent the group that has deviated most far from the common trunk of gastropods in the process of evolution. All pulmonate snails have adapted to life either on land or in fresh waters, and if some of their representatives are sometimes found in the seas, then only in highly desalinated areas. The shells of pulmonary mollusks are most often spirally twisted and very diverse in shape - from tower-shaped or valval to disc-shaped. In a relatively small number of species, the shell has taken the form of a cap covering the entire body on top, like in snails living in fast-flowing rivers. In other species, this cap covers only a small part of the body and is a vestige of a shell, as we see in many land snails. Finally, in land snails we encounter cases where the shell is completely overgrown with the mantle, sometimes accompanied by the complete disappearance of the shell. In species with a well-developed shell, it exhibits a clear spiral twist and is usually twisted to the right; however, there are groups of pulmonate snails in which the shells are twisted to the left, and specimens with a right-handed shell are an exception. The mouth of the shell usually remains open, since the operculum is preserved only in representatives of the family Amphibolidae. In a small ancient group of land pulmonate snails of the family Glausiliidae, the mouth is closed by a special shell valve - the clausilium, which rests on a complex system of plates. Clausilium superficially resembles the operculum of prosobranchs, but is of a completely different origin. Another way to protect against unfavorable conditions environment, for example from drought or cold, serves to tighten the opening of the shell with a film of mucus containing calcium, hardening in the air, the so-called epiphragmon. Between the membrane and the body of the snail, which is deeply drawn into the shell, there usually remains a layer of air. The degree of reliability of the protection created in this way can be judged from the data of experiments during which garden snails were exposed to low temperatures. Under the protection of the epiphragm, the snails endured temperatures of 110 and 120 °C below zero for several periods, with the exception of those specimens in which this phragm was cracked. In addition, there are known examples of land snails surviving extreme heat and drought thanks to this adaptation. The abundant and rapid secretion of mucus necessary for the formation of the epiphragm is facilitated by the so-called “teeth” of the mouth, especially characteristic of species living in arid conditions. In some species, the tooth consists of very numerous strong convexities on the inner wall of the mouth; in others, they look like thin and sharp plates extending along the inner wall of the whorl far into the depths of the shell. All these formations, when the body of the snail is pulled into the shell, press on the soft tissues and squeeze out the mucous secretion, which forms the epiphragm. When unfavorable conditions occur, aquatic pulmonary snails resort to blocking the mouth of the shell, which also closes the opening of the shell with a layer of mucus with an air gap between it and the body; This is how they sometimes even freeze into the ice and survive the winter without harm to themselves. Shellless land snails - the so-called slugs - are much less protected in this regard. Severe drought, bright sunlight in the summer heat, severe cold, force slugs to look for shelters under various covers, for example, under a layer of fallen leaves, in cracks under the bark of rotting stumps, or to hide between clods of soil, sometimes climbing quite deep into the ground; moisture is retained there and temperature fluctuations are less severe. All pulmonary snails are characterized by smooth gliding movement on the soles of their feet, in the front part of which there is a highly developed gland that secretes mucus. The latter wets the sole and protects its skin from damage, reducing friction on the hard surface of the substrate. The cochlea moves forward due to wave-like contractions running along the soles from back to front, caused by the interaction of the longitudinal and sweat muscles. Moving forward, the mollusk usually extends its tentacles using them as a sense of touch. In freshwater forms, the head has such tentacles, at the base of which there is a pair of eyes. Land snails often have two pairs of tentacles, and some forms also have a third pair - tentacle-like appendages located at the edges of the mouth. The eyes of terrestrial animals are located differently than those of freshwater ones at the ends of the tentacles. Of the other sense organs, balance organs are developed - statocysts. Aquatic forms also have a poorly developed osphradium.
One of characteristic features pulmonary mollusks, which determined the name of the subclass, follows the respiratory system and the transformation of the cavity into a lung. This occurs by fusion of the free edge of the hanging mantle with the cover of the front part of the body so that a small respiratory opening remains - the cneumostome, through which the mantle cavity communicates with the external environment; the walls of the cneumostoma can close. The fusion of the mantle with the integument occurs in the early stages of embrygenesis, which indicates the antiquity of the origin of pulmonary mollusks. On the inside of the mantle cavity, on the inside, there is a dense plexus of vessels into which oxygen enters through diffusion. Gills in pulmonate snails are found only as an exception. Thus, terrestrial and freshwater pulmonary mollusks breathe atmospheric air, in connection with which freshwater forms must from time to time rise to the surface of the water and draw air into the mantle cavity. The heart of pulmonary snails consists of one ventricle and an atrium. The nerve ganglia are more or less clearly concentrated and form a peripharyngeal ring. Among pulmonate snails we find herbivorous, omnivorous, and predatory species. Predatory pulmonate mollusks feed on other snails and sometimes on worms. Pulmonary snails have a well-developed radula, and herbivores also have an unpaired horseshoe-shaped jaw. The teeth on the radular plates are especially long and pointed and resemble the shape of vertebrate fangs. The pharynx is well developed. The ducts of the salivary glands open into it. The digestive gland, the liver, flows into the muscular stomach. The intestine forms a loop, and the anus is usually located near the inhalation opening on the right side of the body. Next to the anus there is usually the external opening of the only kidney, which is connected to the pericardial sac (pericardium). The reproductive apparatus of pulmonate snails is particularly complex. The gonad is hermaphroditic. The common duct extending from it is then divided into male and female parts, both of which have a number of adnexal formations. The female part includes the albuminous and shell glands, the spermatic receptacle, and sometimes a number of other glandular appendages. The most highly organized representatives of the subclass have a complex male copulatory organ. Some species are characterized by the formation of spermatophores, i.e., special receptacles for the seed. When mating, both partners mutually fertilize each other, and the mating itself is usually preceded by “love play.” In some forms, during mating, special calcareous needles penetrate into the body of the partner - “love arrows”, which serve for sexual arousal. They are formed in special sections of the reproductive system - the bags of “love arrows”. Pulmonary snails lay eggs either in a common gelatinous cocoon of one form or another (freshwater species), or separately, although in a common clutch (terrestrial species). Each egg is surrounded by a significant supply of nutritional material, and in some forms the ratio of the mass of the egg to the mass of the surrounding protein is 1: 8000 (in Limax variegatus). Development occurs without a free-swimming larval stage; An almost fully formed snail emerges from the egg. Pulmonary snails are divided into two orders.
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
The 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.
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limpet
marine gastropods that have a cap-shaped shell and are able to stick to a solid substrate with their feet, which unites them into a special life form. To M. b. include representatives of the family Patellidae, Tecturidae (subclass of prosobranchs, more precisely compulsory branchials), Siphonariidae (subclass of pulmonates), etc.
Wikipedia
limpet
limpet- a common name for various salt and freshwater snails (aquatic gastropods). It refers to snails with a simple shell, usually conical in shape, not coiled.
Members of the clade, true marine limpets that live in marine basins, are most often referred to as limpets; however, conical shells arose several times during the evolution of gastropods in various clades with gill and pulmonary respiration. The name comes from the characteristic “saucer-shaped” shape of the shell. Many mollusks that have such a shell belong to different taxa:
- Heterobranchia, a group of Opisthobranchia, for example
- Heterobranchia, Pulmonata group, e.g. Siphonariidae, Latiidae,
For example
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For example
A study of limpet teeth has revealed that they are the most durable biological structure known.
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 away from the stone it is holding on to, it takes a lot of effort - the slightest touch, and the limpet is pressed 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.
Patella ulyssiponensis Gmelin, 1791 Taxonomic position Class Gastropoda. Order ancient gastropods (Archaeogastropoda). Family of limpets (Patellidae). Conservation status Endangered species (1).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.
