Poisonous gastropod mollusk cone: types, description, structure

2024 Author: Henry Conors | [email protected]. Last modified: 2024-02-12 02:54

There are about 600 varieties of cone mollusks in the world. They differ in size and color. There are small specimens that are hard to notice among the sand, but there are also huge representatives the size of a human palm. However, despite the external differences, all representatives of these beautiful sea snails are incredibly poisonous. The ability to release poison into the body of the victim helps cone mollusks to hunt, but meeting with such a snail is a mortal danger to a person.

According to the estimates of observers, 2 or 3 people die every year from the bite of cones, while the statistics of deaths from shark attacks are half that. It's all about the visual appeal of the cones and their extraordinary value for collectors from all over the world, which lures divers and shell collectors to them. There is a known case when a collector from Germanypaid more than 200 thousand marks.

Habitat

Cone mollusks live in the waters of the tropics and subtropics. These are the regions of the Indian and Pacific Oceans, waters from the Red Sea to the Sea of Japan. Some species are found even in temperate latitudes, for example, you can see representatives of these gastropods in the Mediterranean Sea, where tourists of our country most often rest. Clams have chosen sandy deposits and small reefs of the waters of Australia and the Philippine Islands.

Danger to people are shellfish in shallow water. Many cases are described when cones injected poison into the leg of a bather wandering along the coast. The divers who swim around the reef also suffer. The incredible beauty of the mollusk beckons to reach out to it and take the shell as a keepsake. The gastropod mollusk only seems to be a defenseless snail, in fact it is a formidable and skillful predator, capable of killing a person weighing 70 kg with one bite.

The structure of gastropods

The molluscs got their name because of their cone-shaped shell. Outwardly, it comes in a variety of colors, which helps the predator to be invisible among the grains of sand on the seabed. The internal structure has three sections. This is the head, torso and leg. The body of the cone mollusk has a mantle supplied with glands on all sides. They secrete calcareous substances that serve as the basis of the shell in which the mollusk hides. It has two layers - thin organic and durable calcareous, resembling porcelain in appearance.

On the headthere are tentacles, eyes, a mouth opening with a movable radula, inside of which there are teeth. At the cones, it has changed into a kind of harpoon, inside it there is a cavity through which poison from the gland flows into the victim. Near the mouth opening, many varieties of cones have outgrowths that look like a worm. This is an excellent bait for fish that the snail preys on. The fish, getting into the mouth, is pulled entirely into the goiter, which is associated with the digestive system. After processing food, the remains go out through the ectodermal intestine. The mollusk moves slowly, crawling along the bottom of the sea on a flat movable leg.

Predator

Most small cones feed on worms or other shellfish, but there are varieties that prey on small fish. These subspecies include the geographic cone mollusk. This is a dangerous representative of the gastropods, which is easy to identify among other mollusks in appearance. Its shell reminded the discoverers of a geographical map.

Indeed, brown spots on the surface of the shell resemble continents with jagged edges, which are scattered across the vast "ocean" of a lighter shade. A photograph of this dangerous mollusk can be seen above. Crawling on its foot over the rocks of the reef, this type of cone blends perfectly with the outlines of the environment. He is hard to spot, so he is considered a fairly successful hunter. He swallows small fish whole, and pulls a goiter on large prey, stretching to the required size, and calmlydigest food further. A special difference between the geographic cone and the rest is the ability to lure fish by stretching its mouth in the form of a funnel with a diameter of up to 10 cm. Small fish can simply swim into it, like into a cave.

Features of hunting

As you already know, the structure of gastropods is fully adapted for successful fishing. Cones hunt at night, and during the day they hide in the thickness of the sand. The olfactory organ is the ofstradium, which analyzes the chemical composition of the water coming from outside. This helps to detect prey and release the harpoon instantly.

This is a pointed tooth with a passage for poison inside. On a signal, when the radula is thrown out and the target is hit, the proboscis is compressed and the poison is injected with force into the victim. It acts instantly, completely paralyzing the fish. Then a slow cone pulls her up to her crop and swallows her whole.

Danger to humans

Depending on the type of cones, the reaction of the human body to a shellfish injection is also different. The sting of a harpoon can deliver moderate pain with signs of a local inflammatory reaction. There will be redness and slight swelling at the bite site. The poison of cones is dangerous due to the presence of conotoxins, first discovered by the American researcher B. Oliver. It affects the nerve endings and can cause paralysis of the respiratory system, which leads to death.

The effect of such a poison is comparable to that of a cobra. It blocks signals from the nervesfibers to the muscles of the body. As a result, all organs become numb and the heart stops. Studies conducted by scientists on the composition of the poison and its effect on living organisms have shown that conotoxins are able to force mollusks to crawl out of tightly closed shells. Observations of mice that were injected with a dose of poison surprised scientists. The rodents began randomly jumping and climbing the walls of the cage.

First aid to the victim

Of all known cases of these mollusk bites, more than 70% of the victims were attacked by a geographic cone. Most often, death occurred when a person was deep under water. At risk are divers and divers for beautiful shells.

Inexperienced exotic lovers grab the narrow part of the shell with their hands. This is a huge mistake, since this is the area where the mouth with the poisonous harpoon of the clam is located. If you have already decided to take this dangerous predator in your hands, then this is done from the rounded side of the shell. It is advisable to generally avoid encounters with a poisonous mollusk cone, but if he has bitten, then you need to act very quickly, since paralysis occurs after a short period of time.

Due to the fact that the poison is composed of several complex toxins, there is no antidote. The only correct solution is bloodletting. The wound is washed with fresh water and immobilized under pressure. It is impossible to warm and wrap the bite site, otherwise the poison will spread faster through the blood. It is not necessary to wait for the appearance of signs of paralysis, it is urgently necessary to take the victim to the nearest hospital. ATmay need mechanical ventilation on the way.

The poison of these mollusks does not cause allergies, so the locals are saved from the bite of the cones by cutting the wound with a knife and squeezing out a lot of blood.

The use of poison in medicine

Mollusk venom contains many biochemical conotoxins that have different effects on the human nervous system. Some of them have a paralyzing effect, while others anesthetize the bite site. Moreover, the reaction occurs instantly, which is very interested in medical scientists.

After a series of studies revealed an interesting fact. The poison of sea cones perfectly anesthetizes seriously ill people, while, unlike the usual morphine, it does not cause addiction and drug addiction. Thanks to the work of scientists, a drug called Ziconotide has appeared, which is considered a successful analgesic.

Active work is underway to study the effects of conotoxins on humans in the treatment of Parkinson's and Alzheimer's diseases, as well as epilepsy.

How poison is obtained

In special laboratories, a small fish is placed in front of the mollusk and teased until it prepares for an attack. Just before the harpoon is thrown, the fish is quickly replaced with a silicone model.

A sharp tooth breaks through the wall of the substitute and injects poison into the internal cavity. For this, the grateful collectors reward the cones with fish. Both are satisfied.

Interest for collectors

It is not surprising that the variety of types and colors of these "porcelain" shells attracts the attention of collectors around the world. The fashion for such exhibits did not appear in our time. A document was found dating back to 1796, which tells about an auction held in Laynet. It featured three lots. The first is a painting by Franz Hals, given for ridiculous money at that time, the second is the famous painting "Woman in Blue Reading a Letter" by Vermeer (sold for 43 guilders). The painting is currently in the Royal Museum in Amsterdam. The third lot was a 5 cm long cone shell that sold for 273 guilders.

In Eastern countries, small shells were used as bargaining chips. A cone called "Glory of the Seas" is still considered the most beautiful shell in the world. Even today, a marine mollusk with a rare type of shell is valued at several thousand dollars.

Now you know a lot of interesting facts about the life of these unique sea creatures.