Macropinna, or barrel eye - amazing underwater fish With transparent head.
A fish with a transparent head... is that conceivable? Does such a creature really live on planet Earth? Our fauna presents more and more surprises each time, revealing to us the secrets of the most mysterious and extraordinarily beautiful animals. The barrel eye is that same transparent-headed fish. Which unusual name! This fish is also called smallmouth macropinna. This creature belongs to the class of ray-finned fish, is a representative of the order Smelt-shaped, containing the family Opisthoproctaceae. Today the barrel eye is the only fish from the genus Macropinna.
This deep-sea inhabitant of the seas was discovered in 1939. But the devices of that time did not allow studying this creature, so scientists remembered it again only 70 years later, when the study depths of the sea became accessible thanks to technological progress.
Fish with a transparent head - what does it look like?
Macropinna has a translucent forehead, through which part of its insides, especially its eyes, can be seen. When light hits the fish, its eyes take on a bright green hue. Why is this happening? The secret is in a special substance that seems to filter the flow of light. The expressive eyes of the macropinna are located in a reservoir filled with liquid, which is located in the frontal part of the head. But if the eyes are inside the head, then what are the holes in the fish where the eyes are? It turns out that this is nothing more than an organ of smell. With it, fish detect various changes in the surrounding aquatic environment.
The size of the barrel eye is small - the fish grows no more than 15 centimeters in length.
Where does the smallmouth macropinna live?
Its habitat is considered to be temperate and subarctic waters Pacific Ocean, or rather, its northern part. This creature with a transparent head can be found near the northern coast of Japan, near the Kuril Islands. Macropinna is found in the Bering Sea, off the coast of Canada. In addition, barrel eye populations also live in the Gulf of California, near Mexico.
Lifestyle of a fish with a transparent head
The depth at which the barrel eye lives is estimated in hundreds of meters (500 m - 800 m). For such deep living, nature provided the macropinna with special fins, with the help of which the animal can deftly move and maneuver in the water column.
The digestive system is also designed in a special way; it is adapted to digest various small animal organisms that live deep under water.
Macropinna is not a very active fish; it moves slowly, and sometimes can even freeze in one place. But she is a wonderful hunter. Thanks to its eyes, capable of seeing both horizontally and vertically, the fish watches the prey and will never miss it. When the prey swims close to the barrel eye, it is immediately captured. Naturally, she has no way back.
Do you think green is fish brain? But no! It is her amazing eyes, which can look not only forward, but also upward. What does the smallmouth macropinna eat?
The main food for this fish is a variety of zooplankton. Various crustaceans, siphonophore tentacles and other small animal organisms enter its stomach.
Despite the fact that the smallmouth macropinna (lat. Macropinna microstoma) was discovered back in 1939, it was only recently possible to study it. Previously, when examining the transparent head of this deep-sea fish, scientists could not figure out how it sees prey, because its gaze must always be directed upward.
In fact, those specimens that meticulous researchers came across were severely injured when rising to the surface. Only 70 years later, in 2009, the world was able to see photographs of a living macropinna. At the same time, the structure of the eye of this unique underwater resident became known.
And the visual organs of the smallmouth macropinna are cylindrical in shape, for which it was nicknamed the barrel eye. The transparent periocular bones, together with the elastic covering membrane, provide their protection. It was this shell that was lost when the unfortunate fish fell into the net and was thrown out at the stern of the ship.
The eyes themselves are located in a chamber filled with a special liquid. They are separated by a bony septum, which also houses the brain. True, for this it is slightly extended back and expanded.
At first glance at a photograph of a macropinna, it may seem that the fish has eye holes that are located directly above the mouth. These are actually the olfactory organs - large, rounded pockets containing olfactory receptor lattices. The barrel eye has a large throat and a small mouth, so it cannot catch large prey.
The fish itself is small - up to 15 cm in length. Her entire body, except her head, is covered with dark scales. The rounded fins are quite large. It is they who help the macropinna remain practically motionless, hovering in the water column. Wherein pectoral fins She holds it horizontally, and tilts her abdominal ones at an angle of 30 degrees. At the slightest danger, the barrel eye quickly presses all its fins to its body and swims away with the help of sharp beats of its tail.
These unusual fish live in the north of the Pacific Ocean, preferring its temperate and subarctic waters. They were most often found off the coast of Japan and the Kuril Islands, as well as in the Bering Sea, near the western coasts of the USA and Canada and south to the Gulf of California. Smallmouth macropinna loves depths from half a thousand to 800 meters. Moreover, the more meters from the surface of the water, the larger the size of the fish itself.
The barrel eye feeds on various zooplankton: small crustaceans, cnidarians, and also swallows siphonophores directly along with their cnidocytes. The fish hunts in two ways: it either waits until the prey descending down is at mouth level and grabs it, or it itself raises its head up to catch the prey swimming above its head. Her peculiar eyes, which either look up or are directed horizontally, help her a lot in this.
Scientists suggest that the macropinna acquired a transparent shell as a result of evolution as protection from cnidocyte siphonophores. Cnidocytes are a kind of stingers that siphonophores use to attack enemies and protect themselves from predators. Obviously, in the case of the barrel eye, this weapon was not very effective.
Smallmouth macropinna, or barrel eye (lat. Macropinna microstoma) is a species of deep-sea fish, the only representative of the genus Macropinna, belonging to the order Smeltfish. They have transparent head, through which they can see with their tubular eyes. The head, through which the fish watches for prey, helps protect the eyes.
Macropinna microstoma - comparatively small fish, the largest known specimens reached about 15 centimeters in length. The body is covered with large dark scales, the fins are large, wide and rounded. This species is characterized by a long intestine with numerous blind processes, a wide pharynx and a narrow mouth, which is the main limitation on the size of prey suitable for consumption.
First opened in 1939. Lives on quite great depth, therefore little studied. In particular, the principle of fish vision was not entirely clear. It was believed that she must experience very great difficulties due to the fact that she can only see up. Only in 2009 was the structure of the eye of this fish fully studied. Apparently, when trying to study it earlier, the fish simply could not tolerate the pressure changes.
Valuable video captured by underwater vehicles with remote control in 2004, helped biologists understand how the fish species Macropinna microstoma sees and hunts. The fish's tubular eyes and transparent head have puzzled scientists since 1939, when macropinnae were first caught. The process of studying these fish was further complicated by the fact that after Macropinna microstoma entered the net, a “bubble” burst, protecting the head structures from exposure to the external environment.
Previously, biologists had established that the eyes of fish see very well even in almost complete darkness, that is, they successfully collect light. And these representatives of the family Opisthoproctidae live at a depth of 600-800 meters off the coast of Central California.
However, scientists were surprised by the fact that the fish’s eyes look only in one direction, namely upward, to the surface of the ocean, where a potential victim can be detected by its silhouette. Given that macropinnas have a very limited field of vision, biologists could not understand how the fish managed to capture prey with their small mouths.
Bruce Robison and Kim Reisenbichler from Research Institute Monterey Bay Aquarium Institute (MBARI) showed that the eyes of Macropinus can still rotate inside the transparent head filled with liquid. In this way, the fish can concentrate its gaze on the prey it is hunting or eating.
In the video recorded by underwater vehicles, the fish hangs in the water column almost motionless. In the light of the streetlights, her eyes appear bright green. Scientists also saw for the first time that there is that same transparent “shield” around the top of the head, and the cavity under it is filled with liquid.
Robinson and Reisenbichler were doubly lucky: a little later they were able to catch several living specimens of Macropinna microstoma. Over the next hours, the behavior of these fish was studied in a special aquarium, and scientists confirmed their guesses - the tubular eyes rotate when the macropinna changes the position of its body from horizontal to vertical.
Biologists have also discovered other adaptations to the deep-sea lifestyle: wide, flat fins allow very precise maneuvering in the water and the fish’s body remains almost motionless; the digestive system makes it possible to digest many types of small drifting animals. Fragments of the body of jellyfish were even found in the stomachs of two individuals.
Scientists believe that most At the same time, the fish swims in a horizontal position, its eyes turned to the surface. Green lenses can filter incoming sunlight. When an animal that reveals itself by a bioluminescent glow (for example, a jellyfish) floats above it, the fish turns vertically, its eyes begin to look straight, and hunting and feeding begin.
IN digestive system fish of this species were found in zooplankton different sizes, including small cnidarians and crustaceans, as well as siphonophore tentacles along with cnidocytes. Considering that zooplankton in large quantities accumulates on the tentacles of siphonophores, where it can be obtained deep sea fish, as well as the remains of cnidarians found in the digestive system of Macropinna mіcrostoma, we can come to the conclusion that the continuous transparent membrane above the eyes of this species evolved evolutionarily as a way of protecting cnidarians (especially siphonophores) from cnidocytes.
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Macropinna is a mysterious fish of the ocean depths. Macropinna microstoma – fish are small in size and, even in the most in rare cases, its size does not exceed 15 cm.
Dark scales cover the main part of the body of such a creature, which spends its life in the depths of the ocean. On photo of macroninna When examining its contours, rounded, wide and large fins are clearly visible.
The fish's eyes are tubular, its throat is impressive, and its mouth is narrow. This inhabitant of the waters, otherwise called: smallmouth macropinna, discovered and described in the last century.
But it was only at the beginning of this year that photographs were obtained mysterious creatures, revealing the secret of the unique details of their structure. The peculiarity is that the head is transparent, which is not typical for any creature in this world.
It is interesting to note that such a fact was not so easy to find out earlier, since there was no equipment yet that clearly reflected the details of the appearance of creatures living on great depths. And the translucent, fragile dome that nature endowed this living organism with was immediately destroyed the moment it was removed from the water.
Through the transparent forehead of such an almost fantastic creature, one can somehow see the internal structure. The most interesting element of its structure is, first of all, the impressive unique eyes, located in a reservoir filled with a special liquid, but not outside, like in ordinary earthly creatures, but inside the body. And on the surface of the transparent dome there are only olfactory organs that detect various changes in the surrounding world.
Macropinna is a representative of the class of ray-finned fish, common in temperate latitudes and subtropics, found in the northern hemisphere in the depths of the Pacific Ocean and, adjacent to it, the waters of the Bering Strait and the Sea of Okhotsk.
Such creatures are also found within the waters of Kamchatka and Japan, in the depths of waters reaching the coast of Canada. In the opisthoproctaceae family, to which these living organisms belong, today, according to scientists, there are about a dozen species.
Character and lifestyle of micropinna
This animal has another name - barrel eye for the appropriate arrangement of tube-shaped organs of vision, which turn out to be very useful in the environment where the life of fish takes place, living in the ocean depths under a water column of five to eight hundred meters.
Sun rays little penetration into these remote areas, which left an imprint on the visual perception of underwater creatures, capable of perceiving even in pitch darkness.
The light entering the eyes of the fish lights them up brightly green. The reason for this phenomenon is a special substance that filters light rays. This is considered in the characteristics of such creatures as another interesting fact , But smallmouth macropinna- a creature so mysterious that with her in-depth study of the secrets it only becomes greater.
Fantastic inhabitants of distant depths never cease to amaze scientists, but this is understandable, because these are creatures far from civilization and the property of a completely different world.
It is difficult for a person to remain in inaccessible and hazardous environment their habitat, but they cannot exist in our world. At great depths, where they are used to living, even the pressure is completely different. That is why, if you take such fish out of the water, the fragile frontal part of their head bursts from its drop.
The structure of the fish's fins is also an excellent adaptation for comfortable swimming and impressive maneuvers in deep ocean waters. However, it cannot be said that such creatures exhibit high vital activity. They are quite slow, and when swimming, they often stop and freeze in one place.
Do these almost fantastic animals have enemies? Science does not yet know enough about this, because it is very difficult to observe the details of the movement and lifestyle of these fish in the depths of the ocean.
Their paths do not intersect with the paths of man. And there is no need for them to intersect. The inhabitants of the depths do not care about people, and for people, other than curiosity and a thirst for knowledge, there is no practical benefit for the stomach from them either. The peculiarities of their anatomy make it difficult for humans to eat such creatures.
Nutrition of macropinna
Slowness smallmouth macropinna – fish with transparent head, does not prevent her from being a successful hunter. Having special barrel-shaped eyes located inside the head and protected by a transparent shell, such creatures are able to perceive the world, both horizontally and vertically, which allows them to conduct successful observations of the intended prey and not miss any of the details of its movements. If the victim has the temerity to swim closer to such a big-eyed enemy, he immediately finds himself caught, meeting his sad end.
During the day, such fish make regular movements, rising, although not long distances, to the upper layers of water, where they get their food, and at night they descend back.
It is not difficult to understand that aquatic hunters are predators. But they are not interested in big prey. Due to the presence of a small mouth (for which they received the name smallmouth), they are able to feed mainly on plankton, siphonophore tentacles, crustaceans and other small animal organisms.
Reproduction and lifespan of macropinna
Macropinna – fish little studied, as already mentioned. Scientists are just beginning to learn the unique details of the lifestyle of these creatures that live deep at the bottom of the ocean. The same applies to methods of reproduction, about which not much is understood.
But it is known for certain that females amazing fish spawn in large quantities. And the fry that emerge from it first have an elongated body, having little resemblance to their parents. But then numerous metamorphoses begin to occur to them, until they accept natural look adults.
The difficulty of observing deep-sea animals step by step throughout their entire life was a consequence of the fact that its duration is another mystery for scientists.
However, these mysterious representatives of the fauna were still able to be placed and successfully kept in an aquarium located in California. The building that became the new home for mysterious fish, is considered one of the largest in the world, and it features many amazing views aquatic fauna housed in 93 tanks.
And every day amazing, fantastic and unique creatures have the opportunity to watch millions of curious spectators. Therefore, we can hope that soon all the secrets of the macropinna will be revealed.
Smallmouth macropinna, or barrel eye (lat. Macropinna microstoma) is a species of deep-sea fish, the only representative of the genus Macropinna, belonging to the order Smeltfish. They have a transparent head through which they can see with their tubular eyes. The head, through which the fish watches for prey, helps protect the eyes.
First opened in 1939. It lives at very great depths, so it has been little studied. In particular, the principle of fish vision was not entirely clear. It was believed that she must experience very great difficulties due to the fact that she can only see up. Only in 2009 was the structure of the eye of this fish fully studied. Apparently, when trying to study it earlier, the fish simply could not tolerate the change in pressure.
The first photographs of live fish were taken only in 2004.
Macropinna microstoma is a relatively small fish; the largest known specimens reached about 15 centimeters in length. The body is covered with large dark scales, the fins are large, wide and rounded. This species is characterized by a long intestine with numerous blind processes, a wide pharynx and a narrow mouth, which is the main limitation on the size of prey suitable for consumption.
Macropinna microstoma is distributed in the subarctic and temperate waters of the North Pacific Ocean: off the coast of northern Japan, the Kuril Islands, in the Bering Sea, off the west coast of Canada and the USA, south to the Gulf of California (Mexico).
Vertically this type It is found at depths from 500 to 800 meters, with the largest specimens being caught, of course, at greater depths.
Fish in their normal habitat are usually motionless, or move slowly in a horizontal position. All fins are fully extended; The pectoral fins are oriented horizontally, while the pelvic fins are inclined downwards at an angle of approximately 30°. Due to the large open fins, the fish reaches a stabilized position in the water column. When the fish moves, all fins remain fully extended, and movement is provided by the caudal fin. In case of danger, the fish presses its pectoral and abdominal swimmers to its body, and makes sharp jerks with its tail beats. Thanks to special structure eye muscles, these fish are able to move their cylindrical eyes from the vertical position in which they are usually located, to the horizontal position when they are directed forward. In this case, the mouth is in the field of view, which provides an opportunity to capture prey.
Such features of the visual apparatus make possible two fundamental approaches to searching for food. Firstly, the fish is able, being in a horizontal position with its eyes directed upward, to notice potential prey above it. As the fish moves its body upward (with its mouth towards the prey to grab it), the eyes move forward, keeping the prey in sight. Secondly, with a constant horizontal position of the body, the fish is able to follow potential food objects that descend from above, moving its eyes. When this object hits the level of the mouth, the fish grabs it.
In the digestive system of fish of this species, zooplankton of various sizes were found, including small cnidarians and crustaceans, as well as siphonophore tentacles along with cnidocytes. Taking into account the fact that zooplankton accumulates in large quantities on the tentacles of siphonophores, where it can be preyed on by deep-sea fish, as well as on the remains of cnidarians found in the digestive system of Macropinna microstoma, we can come to the conclusion that the continuous transparent membrane present in this species above the eyes arose evolutionarily as a way of protecting cnidarians (especially siphonophores) from cnidocytes.
The most notable feature of this species is the transparent, dome-shaped shell that covers the top and sides of its head, and the large, usually upward-pointing, cylindrical eyes that lie underneath this shell. A dense and elastic covering shell is attached to the scales of the back and sides, and on the sides - to the wide and transparent periocular bones, which provide protection for the organs of vision. This covering structure is usually lost (or at least very badly damaged) when fish are brought to the surface in trawls and nets, so its existence was not known until recently.
Under the covering shell there is a chamber filled with a transparent liquid, in which, in fact, the eyes of the fish are located; The eyes of living fish are bright green. The eyes are separated by a thin bony septum, which, extending backward, expands to accommodate the brain. In front of each eye, but behind the mouth, is a large rounded pouch that contains an olfactory receptor rosette. That is, what at first glance appears to be eyes in photographs of live fish is actually an olfactory organ.
The green color of the eyes of this fish is caused by the presence of a specific yellow pigment in them. It is believed that this pigment provides special filtering of light coming from above and reduces its brightness, which allows the fish to distinguish the bioluminescence of potential prey.
Scientific classification:
Kingdom: Animals
Type: Chordata
Class: Ray-finned fish
Squad: Smelt-like
Family: Opisthoproctaceae
Genus: Macropinna Chapman, 1939
View: Smallmouth macropinna (lat. Macropinna microstoma)
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