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Sea stars - animals with unusual shape body, thanks to which they attracted the attention of people in ancient times. Sea stars belong to the phylum Echinodermata, in which they are isolated in separate class, numbering almost 1600 species. The closest relatives of these invertebrates are the ophiurs, or serpenttails, which are very similar to them, and the more distant holothurians and sea urchins.
Fromia elegant starfish (Fromia monilis).
home distinguishing feature starfish it is, of course, the shape of the body. In general, the body of starfish can be divided into a central part - a disk, and lateral outgrowths, which are commonly called rays or arms. These animals are characterized by radial symmetry, so their body is divided into symmetrical sectors, the number of which is usually five. However, among starfish there are organisms with a large number axes of symmetry: in some species their number can reach 6-12 and even 45-50.
Nine-armed starfish (Solaster endeca).
Each sector, respectively, includes a part of the central disk and a hand. It would seem that such a structure of the same type should result in the uniformity of these living organisms. But just the shape of the body of starfish is very variable. First, the relative length and thickness of the rays varies greatly: in some species they are elongated and thin, in others they have a triangular shape, sharply tapering towards the end, in others the rays are so short that they practically do not protrude beyond the edges of the central disk. The stars of the last type have a very high central disk, so they resemble pillows. Thus, in most types of starfish, the length of the rays is 3-5 times greater than the diameter of the central disk, in the longest-armed ones it is 20-30 times, and in pillow-shaped ones it tends to zero.
This bright ottoman seabed in fact, the New Guinean culcita starfish (Culcita novaeguineae).
Secondly, starfish differ in surface texture and color. Here the variety simply defies description - smooth, spiny, prickly, rough, velvety, mosaic; monochrome and patterned, bright and faded. The color scheme of these animals includes almost all colors, but most often there are various shades of red, less often blue, brown, pink, purple, yellow, black. Pale starfish usually live in deep water, while shallow water species are bright.
This is the same New Guinea culcite, but of a different color.
At first glance, starfish seem primitive, because they do not have any noticeable sensory organs, brain, internal organs are poorly differentiated, but this simplicity is deceptive.
Linkia starfish (Linckia laevigata) is bright blue in color, its rays look like sausages.
First of all, it should be noted that starfish have an internal skeleton. They do not have a backbone and separate bones, but there are many calcareous plates connected to each other in an openwork system.
Openwork plexus of skeletal elements on the surface of a starfish.
In a young starfish, the skeletal elements are hidden under the skin, but over time, the skin over some of the calcareous spines is erased and they become visible from the outside. It is these spines that give starfish their spiky appearance.
The spikes on the surface of the starfish are covered with skin, but some of them are already exposed and have a shiny surface.
In addition, calcareous plates can be seen on the upper side of the body in many species, fused together or forming a network.
A bizarre pattern formed by the skin and skeletal elements of the starfish.
Finally, the third element affecting appearance starfish are pedicellariae. Pedicellaria are modified needles that look like tiny tweezers. They play an important role in the life of the starfish, with their help it cleans the upper side of the body from debris and sand. All skeletal elements are interconnected by muscles, therefore, after the death of a starfish, its skeleton crumbles into lime plates and there is not a trace left of the animal.
The starfish acanthaster, or the crown of thorns (Acanthaster ellisii) has prickly and poisonous thorns.
The muscular system of starfish is relatively poorly developed. Each ray has a muscle cord that can bend the ray upwards, and this, in fact, is what the muscle movements of the stars are limited to. But mobility is not limited at all. Starfish can crawl, dig, bend, swim, but they do not do this with the help of muscles.
Starfish scalloped patiria (Patiria pectinifera) climb algae.
These animals have a special body system - ambulacral. In essence, this system is channels and cavities connected together and filled with liquid. The starfish can pump this fluid from one part of the system to another, causing its body parts to bend and move. The centerpiece of this system is the ambulacral pedicles, tiny blind outgrowths of the ambulacral canals on the underside of the starfish. Each leg moves independently of the others, but their actions are always coordinated. With the help of these microscopic elements, the starfish can work wonders. For example, it is able to climb a vertical surface, it can stick to the glass of an aquarium for a long time, it can stand on its hind legs, swelling up like an angry cat, or it can, grabbing two beams, push the shells of a mollusk apart. And all this is done by an animal practically devoid of a brain and eyes!
On the underside of the beam, translucent ambulacral pedicles are visible.
In fairness, it should be noted that starfish still have some sense organs. These are eyes located at the ends of each beam. The eyes are very primitive and distinguish only between light and darkness; starfish do not see objects. Sea stars are able to catch chemical substances(analogous to scent), only now they feel them differently. Some species are very sensitive and can crawl to the bait by smell for several days in a row, others can crawl past the victim a couple of centimeters and not smell it. Sea stars have a very developed sense of touch, they try to get rid of the sand that fills them from above, and they also always try to feel their way with the help of small tentacles at the end of each beam. The sense of touch tells the starfish whether it is a prey or a predator. The brain of a starfish is replaced by a group of loosely interconnected cells. Surprisingly, despite such a primitive structure of the nervous system, starfish can develop elementary conditioned reflexes. For example, individuals that were often caught with nets began to get out of them faster than those that were caught for the first time.
At the end of the ray of the starfish asterodiscus (Asterodiscus truncatus) a decorated eye is visible. The beam itself is covered with relief lime plates.
Another strong, straight and figuratively words, the system of starfish is the digestive system. The mouth of these animals is located in the center of the disk on the underside of the body, and the tiny anus is located on the back. By the way, starfish rarely use it (in some species, it generally overgrows), preferring to remove undigested food residues through the mouth. The stomach of these invertebrates has outgrowths extending into rays; reserves are deposited in them. nutrients in case of hunger. And starfish starve regularly, because during breeding they stop eating. The stomach in many species can turn outward through the mouth opening, and it stretches like rubber, taking any shape. Thanks to the expandable stomach, the starfish can digest prey that is larger than it is. A case is known when the starfish luidia swallowed such a large sea urchin that it died, unable to spit out its remains.
In the middle of the central disk of fromia monilis, a tiny anus is visible.
Other body systems are poorly developed in starfish. They breathe through special outgrowths of the skin on the upper side of the body washed by sea currents. They do not have gills and lungs, so starfish are sensitive to lack of oxygen. They also cannot stand desalination, so they are found only in the seas and oceans. The sizes of these animals range from 1-1.5 cm for the miniature spherical star Podosferaster to 80-90 cm for the Freyella starfish.
The name of this starfish speaks for itself - elegant fromia (Fromia elegans).
Sea stars have a global distribution. They are found everywhere in all seas and oceans from the tropics to the poles. Of course, species diversity is higher in warm waters than in cold ones. Most species prefer to live in shallow waters, some even end up on the shore at low tide. But among these animals there are also deep-sea species, including those that live at depths of more than 9 km!
Sea stars in shallow water.
Starfish crawl along the bottom most of the time. They do this very slowly, the usual speed of a medium-sized individual is 10 cm per minute, but a starfish can also “hurry up” at a speed of 25-30 cm per minute. If necessary, these animals climb stones, corals, algae. If a starfish falls on its back, then it immediately turns over with its ventral side down. To do this, the animal bends two rays so that the ambulacral legs on the lower side touch the ground, and then the starfish twists its body and assumes its usual position. Some species are even able to clumsily swim short distances. Sea stars can be called sedentary animals, their tagging has shown that they do not move more than 500 m from the place of the original catch.
The starfish granular coriaster (Coriaster granulatus) looks like a bun.
Despite the outward primitiveness and seeming helplessness, starfish are formidable predators. They are quite gluttonous and never refuse prey, except for the period of gestation of eggs. Only deep-sea species feed on silt, from which they extract food particles; culcite starfish, which prefer to nibble on coral fouling, can also be called conditionally “non-predatory”. All other species actively prey on other animals.
This couple was not romantically connected at all: the starfish Solaster (Solaster dawsoni) eats prickly hippasteria (Hippasteria spinosa).
Most starfish are not picky, they eat everything they can hold with their hands and what their “rubber” stomach can get, without disdaining carrion. Some species can only eat a certain kind food: sponges, corals, gastropods.
Pretty starfish pentagonaster (Pentagonaster pulchellus), which is also called the biscuit starfish for its biscuit-like body shape.
The favorite prey of sea stars are sedentary animals like themselves - sea urchins and bivalve molluscs. The star overtakes the sea urchin by crawling and eats it with its mouth. Bivalve mollusks have shells that close tightly in case of danger, so they are treated differently by starfish. First, the starfish is glued with two rays to the shell valves, and then begins to push them apart. I must say that the ambulacral legs are firmly glued to the substrate due to the adhesive lubricant and one single ambulacral leg can develop a force of up to 30 g! And on each ray of a starfish there are hundreds of them, so she, like a real strongman, pushes the shells apart with a force of several kilograms. However, the starfish does not need to push the shell flaps to its full extent; for a hearty dinner, a gap of 0.1 mm is enough for it! In this truly microscopic gap, the starfish twists its stomach (it can stretch 10 cm) and digests the mollusk in its own home.
Asteria starfish (Asterias rubens) stretches its hand towards a mollusk.
Most sea stars have separate sexes, very few species have both male and female gonads. The gonads are arranged in pairs at the base of each ray. In the starfish asterina, young individuals are first male, and then change it to female. A special exception is the ophidiaster starfish, which has no males at all! Females of this species lay eggs without fertilization, such reproduction is called parthenogenesis. During mating, males and females combine their rays and sweep sperm and eggs into the water. The number of eggs depends on the type of development of the larva and ranges from 200 in those species that bear offspring, and up to 200 million in species with free-swimming larvae.
Mating starfish.
Starfish larvae come in three types. In some species, a free-swimming larva hatches from the eggs, which feeds on microscopic algae, and then attaches to the bottom and gradually turns into a small star. In others, the free-swimming larva has a large supply of yolk, so it does not feed and immediately transforms into an adult form. In starfish that live in cold waters, the larvae do not separate from the mother's body at all, but accumulate near her mouth or even in special stomach pockets. A caring female during this period relies only on the tips of the rays, and the body arches in a dome, under which the offspring is located. Since the larvae are located near the mouth opening, the female does not feed during this period. The larval form is the most mobile in life cycle starfish, it is during this period that the young can be carried by currents over very long distances.
The starfish larva is bilaterally symmetrical.
In addition to sexual reproduction, starfish can also reproduce asexually. Most often this occurs in multi-beam species, the body of the animal is divided into two halves, each of which builds up the missing rays. In other species, asexual reproduction may be the result of regeneration after traumatic injury to the body. If a starfish is artificially divided into several parts, then a new organism will form from each. Even one beam is enough to restore, but a piece of the central disk is required. Sea stars grow slowly, so for many months they look one-sided.
A new individual is formed from the cut off ray of a starfish. This shape is often called a comet.
AT natural environment starfish have very few enemies, since the sharp spines, which can be poisonous, scare away large predators. In addition, these invertebrates, on occasion, try to burrow into the sand so as not to attract attention. Most often, starfish fall on the teeth of sea otters and gulls.
The seagull caught a starfish.
But the starfish astropecten is friends with polychaete worms. Up to five cohabitants can be found on one individual, who prefer to stay on the underside of the body closer to the mouth of the star. The worms pick up the remains of her prey and even put their head in her stomach! A special type of ctenophores live on the Echinaster starfish, which clean the surface of the star from fouling.
These bright spots on the Luzon starfish (Echinaster luzonicus) are ctenophores (Coeloplana astericola).
Since ancient times, people have paid attention to the colorful animals of shallow water, but starfish have not been of any economic interest to them. Only in China are they sometimes eaten, while feeding starfish to pets can lead to their death. This is likely due to the toxins that some species accumulate by eating corals and poisonous molluscs. But with the development of the marine economy, people began to classify these animals as their enemies. It turned out that starfish often eat the bait in bottom crab traps, and also raid oyster and scallop plantations. In a few years (that's how many oysters need to be grown), starfish can destroy an entire oyster jar. At one time, they tried to destroy predators by cutting them into pieces, but this only increased their numbers, because a new starfish grew from each stump. Then they learned how to extract starfish with special trawls and kill them with boiling water.
Very spectacular mosaic starfish (Iconaster longimanus).
by the most malicious pest turned out to be the starfish acanthaster, or the crown of thorns. This very large echinoderm feeds exclusively on corals, after which the crown of thorns leaves only a white lifeless path on the coral reef. At one time, these stars multiplied so much that they literally ate a huge section of the Big barrier reef off the coast of Australia. The unique geological formation was under the threat of destruction. The fight against the crown of thorns was complicated by the fact that its thorns are poisonous to humans, the prick of the crown of thorns causes burning pain, although not fatal. Specially trained divers collected acanthasters with sharp spikes in bags or injected a lethal dose of formalin into the body of a starfish. Only in this way it was possible to pacify the invasion of voracious predators and save the reef. Now all types of starfish are in a safe condition and do not need protection.
The crown of thorns eats the coral.
What do you know about starfish? Beautiful and unusual creatures, with many interesting facts from their lives - in our selection Currently, about two thousand species of starfish are known.
Starfish don't have a brain or blood - to get nutrients, oxygen and other important fluids, a starfish pumps through its body. sea water. It is the resulting water that is distributed throughout the body and forms the “water-vascular system”.
Mistaken to be tentacles, each arm of a starfish has about 15,000 tiny suckers that help the starfish move. 
A starfish is not a fish, but an invertebrate animal.
Sea stars are real predators. They are able to attack their own kind and can easily feast on the small offspring of their own species, i.e. are cannibals.
Stars have two stomachs, one of which they can even push out to digest shellfish. 
Starfish are long-lived, some species live up to 30-35 years. 
Many of the starfish are very dangerous. For example, the crown-of-thorns starfish, common throughout the Indo-Pacific Ocean, is covered in poisonous spines. Growing up to almost half a meter in length, these creatures become dangerous not only for coral reefs, but also for divers and swimmers. 
Starfish are able to easily change gender, and then switch back. True, for such “transformations” several suitable conditions are needed - water quality, temperature and food availability. 
Starfish have eyes - exactly as many as rays, at the tip of the rays there is an eye, which looks like a red spot. They see, of course, not very well, but at least they distinguish between darkness and light. 
Even though starfish live underwater, they lack gills. 
Although the appearance of most starfish corresponds to their name, sometimes there are unusual individuals of a bizarre shape. For example, starfish may be sun-shaped, with numerous rays, or their shape may be rounded. 
The heart of starfish beats at a frequency of 5-7 beats per minute.
The largest starfish can reach 1 meter in diameter and weigh up to 5 kilograms. Solar stars are more active than their relatives, and are able to rapidly pursue their prey, and, having incredible strength, simply tear the shell of molluscs and crustaceans. 
The feeding method that allows the starfish to eat prey much larger than the mouth opening is as follows - since the mouth of the starfish is on the underside of its body, the star, grabbing the prey, wraps its strong arms around it, and then places it under it with a strong push, and then pushes into the stomach. 
They are also one of the most ancient inhabitants of the Earth. Sea stars are about 250 million years old.
Stars move with the help of hundreds of tubes that are attached to the surface, and then move in waves. 
Sea stars live at various depths, up to ten kilometers. 
In the past few years, starfish have begun to multiply actively. This creates a problem, as each individual has an excessive appetite and consumes about 6 square meters of coral per year. In some areas, measures are being taken to destroy stars. 
However, starfish still bring much more useful than harmful - they are important consumers of carbon dioxide - annually, starfish together destroy about 2% of the Earth's carbon dioxide, and this is an extremely large figure within the whole planet. 
Another useful role of starfish is to clean the seabed from carrion, weak and sick creatures of the seabed, as well as from the remains of dead oceanic organisms. 
Starfish go through five stages of growth before becoming adults - during the first month, the stars are free-floating and jellyfish-like, they are small, almost invisible to the eye and tiny plants and animals of the ocean. 
Although most starfish are not poisonous, a large star called the acanthaster or crown of thorns is dangerous to humans. The injections of her needles bring burning pain to a person - if the needle gets stuck in the skin, then it breaks off from the body of the star and begins to infect the human blood with toxic secretions. 
An interesting fact is that if you cut off one of the arms of a starfish, or all at once, without damaging the central part of the body, then they will gradually grow back.
When you first see a starfish, the first thing that comes to your mind is an ordinary souvenir, but in fact it is creature which looks like a star. With its way of life, this entity, as it were, ignores all the usual laws of biology - having neither blood nor a brain, the stars have unique eyes and can digest food outside their body.
External features of starfish
Sea stars are invertebrates, almost symmetrical animals that are found in all oceans. They appeared about 500 million years ago. Most of the representatives of this species are found not at the bottom, but almost on the surface, but there are stars that are found at a depth of 6000 meters. Today, zoology describes more than 1800 species of starfish. Each of the species has its own characteristics, but all representatives are united by the correct symmetrical shape and a number of external features, which does not confuse them with any other species.
As a rule, stars have five or six rays that emanate from the center of the disk. The record number of rays recorded by zoologists is 50, at great depths there are representatives of the species with 10-15 rays. In starfish, the body length can reach one meter, but the most characteristic size is 15-25 centimeters. Stars large in size, can weigh 5 kilograms, they are also called "solar stars". These types of animals are more powerful, they have enough power to break the shell of crustaceans. They hunt their prey and may even pursue it for a long time.
Starfish have a rough or smooth surface, and may be covered with ridges or sharp, poisonous needles. Some of the representatives of the starfish family have a very bright color and are unusually beautiful, it is impossible not to notice their presence in the water. The color range of starfish includes all shades and colors. bright stars live near the surface, and pale, as a rule, at great depths.
starfish nutrition
As for the nutrition of starfish, their diet is quite diverse - they do not disdain to eat carrion, feed on sea urchins, which are several times larger than them, and crabs, they can even attack small fish. Moving along the bottom, they dig small holes and wait for their prey there, which inadvertently approaches the mouth of the star. The feeding process itself is very interesting, the star drags out the stomach and envelops its victim with it. In the process of eating, special enzymes are released that help digest food not inside the star, but outside.
Starfish have a very flexible stomach, 0.1 mm is enough for it to penetrate the gap. It is for this reason that it is enough for mollusks to open their valves a little, as a starfish will already envelop them in their stomach and eat them. The process of eating can last up to 8 hours, everything happens very slowly, but in general, the feeding time depends on the size of the victim. In the industry, the starfish is considered the real enemy of oysters due to the reasons described above. In order to limit the contact of starfish with oysters, they are systematically removed using nets.
Regenerative abilities and reproduction
In many science videos, the starfish regrows lost organs and fully regenerates if there is at least half of the disk or the lost ray. There are cases in science when a fallen limb completely restored the entire disk. There are also types of starfish that reproduce in exactly this way - by fission.
Also present in the species sexual reproduction. Males and females release their eggs into the water, and fertilization takes place outside the body. No matter how strange it may sound, but one female starfish can become the mother of two million larvae. After fertilization, the larvae mix with ordinary plankton, but when they mature, they settle on the bottom and lead an independent life. Some types of stars hatch larvae in their stomach or under a plate. But, this is rare in most cases, fertilization occurs outside the body of the female.
Internal skeleton and muscles
Initially, it may seem that in the absence of the organs of smell and brain, these are primitive animals, but such simplicity is very deceptive. As the science video shows, starfish have a skeleton. Of course, skeleton sea stars do not consist of a spine, but they have calcareous plates interconnected in an openwork system.
In young organisms, this openwork system is not visible, but with age, the skin is erased, and the skeleton begins to show through. It is the protrusion of the skeletal plates that makes the starfish prickly. Some calcareous plates that bulge outward merge together and create the appearance of tentacles. With the help of them, starfish clean the outer part of their plate from sand and various debris. After a starfish dies, its skeleton crumbles and only dust is left of the star. Some starfish have poisonous tentacles and serve as an additional means of hunting small fish and crustaceans.
As for the muscular system, as the science video shows, starfish can move, swim, bend, but all this is not with the help of muscles. They are very weak in this species of animals. All that the muscle is capable of is to lift the beam up.
Some of the starfish can even climb up the algae, such movement is achieved thanks to the ambulacral system of the body. The system is cavities and channels that are filled with liquid, which the star can distill into different parts of its body and thus move. Main Feature of this system is that it provides for small legs on the underside of the star plane. Tiny outgrowths move separately, but in most cases all movements are coordinated and rhythmic. Thanks to these small legs, a starfish can rear up, stick to vertical planes, and even break the shell of a mollusk with two rays.
Sense organs in starfish
Sea stars completely lack all the senses, well, except for the eyes, of course. Eyes are located at the tip of each ray. Sea stars do not distinguish objects and colors, the eyes are very primitive, therefore they recognize only light and darkness.
An analogue of the sense of smell in these animals is the ability to catch chemicals that are present in the water with the body of the body. Animals move not by eye, but by touch. They feel their way in the sand, and with the same sense of touch, they understand who they encountered on the road, with a predator or with a prey. Note that all this happens in the absence of a brain. The brains of starfish replace tightly interconnected nerve cells. Very surprising is the fact that in the absence of a nervous system, as the scientific video shows, starfish are still capable of conditioned reflexes. For example, individuals that have repeatedly fallen into the net are released much faster than those that have got there for the first time.
Area of distribution of sea stars
Sea stars can't stand fresh water, therefore, they are found only in the seas and oceans, where salty water. They move very slowly, on average 10 centimeters per minute. They can climb rocks, algae and corals. Very interesting is the fact that, unlike turtles, which, having fallen on their backs, cannot roll over on their own, starfish immediately return to their usual position.
This species of animals can be safely attributed to sedentary animals; in their entire life they are unlikely to move further than 500 meters from their birth. In their natural habitat, starfish have virtually no enemies. The spiny structure of the body scares off large predators, so they lead quite a quiet life, but can sometimes get into the mouth of gulls and sea otters, which mistakenly take them for fish.
Bright inhabitants sea depths, people have noticed for a long time, but starfish do not carry any economic use, only in China they are occasionally eaten. Sea stars are very sensitive to high temperatures, and you can kill them by simply pouring boiling water over them. Many starfish are poisonous, so it is not recommended to take them with bare hands. This once again proves how changeable nature can be - such a beautiful, and at first glance harmless creature, can deprive big man life in one minute.
These and other inhabitants underwater world you can even see it in person!
Sea stars
classis Asteroidea de Blainville, 1830
These echinoderms usually have a flattened body that smoothly transitions into radial "arms" (5-40) called rays. The shape and structural features of the rays are very diverse: from wide and short, giving the animal pentagonal contours, to thin and long, resembling tentacles. Unlike lilies, the mouth of movie stars and ambulacral furrows are located on the lower surface of the body facing the substrate. 
In those situations where movie stars have an anus, it, like the madrepore plate of the ambulacral system, is located on the upper (dorsal) surface of the body.
All stars are mobile organisms moving along the substrate with the help of ambulacral legs located in ambulacral furrows. Like lilies, movie stars do not have a pronounced anterior-posterior axis and lack any “head end”. Stars are perfect radial animals.
The skeletal plates and spines of movie stars are very diverse, sometimes transforming into special surface organs - pedicillaria. Under a microscope, it is possible to see that pedicellaria is a group of a number of elongated “bones” that work like scissors or tongs. With these tweezers, stars can clean the surface of the body from various fouling organisms that constantly want to settle on these convenient “hosts”.
Most of the movie stars are predators and corpse eaters; stars are known to be detritophages and filter feeders. Often and cannibalism. When capturing a large prey, the star's stomach is able to turn outward from the mouth opening and embrace the prey.
Movie star larvae are called bipinnaria and brachiolaria, but there are also stars with direct development that are able to bear their young and take care of their offspring. Larvae that are able to feed during their own development in plankton are called planktotrophic, and larvae that do not feed on planktonic are called lecithotrophic larvae.
Now about 1500 species of sea movie stars are known, most of which are inhabitants of tropical seas.
In the waters of South Primorye, according to our data, there are 25 species of movie stars. Let's talk about the most typical and often encountered representatives of this class of echinoderms.
Luidia bicepsLuidia quinaria Martens, 1865 bispinosa Djakonov, 1952
This star has a strongly flattened body with 5 long, narrow, tapering rays. The span of rays of luidia reaches 30 cm. On the surface (dorsal) side, the central disk and rays of luidia are dark brown with a violet tint, sometimes almost black, and the lower (ventral) side and sides of the rays are orange-yellow. Along the edges of the rays on the dorsal side, the upper marginal (marginal) plates are clearly visible. The dorsal surface itself is flat and covered with paxillae resembling squares - groups of small needles sitting on one rod. On the sides of the rays there are large flattened needles and small needles extending from the lower marginal (marginal) plates.
They live on silty, silted or sandy soils at depths from 3 to 100 m. Luidia have planktotrophic larvae.
Patiria scallopPatiria pectinifera (Mueller et Troschel, 1842)
This star has a wide flattened disk and very short wide rays pointed at the ends. The dorsal side is somewhat convex, and the ventral side is completely flat. Rays are usually 5, although there are 4,6 and even 7-ray patirias. The span of the rays of the largest specimens reaches 18 cm. The color of the patyria is very variegated: blue with orange and yellow spots on the dorsal side and orange-yellow on the ventral side. The dorsal side of the patiria is covered with plates overlapping each other like tiles, the free edges of which always face the center of the disc. Patiria received its specific name for the scallops of needles located on the ventral side, connected at the base by a soft membrane.
Comb Patiria is a low-boreal subtropical species, found mainly in the regions of Southern Primorye. These stars are very common in the intertidal zone among stones and on rocky ground. On sandy, rocky and silty soils, Patiria are found up to a depth of 40 m. They prefer to settle on coarse sandy areas of the bottom with an admixture of pebbles and large stones with curtains and thickets of Zostera and Phyllospadex algae. Patiria is a predator that prefers to attack medium-sized mollusks.
In the waters of Southern Primorye, Patiria spawn in the second half of August - early September. The larvae of Patyria are planktotrophic.
Solaster pacificusSolaster pacificus Djakonov, 1938
These cold-water stars prefer great depths and are found in South Primorye, as a rule, deeper than 60-70 m.
Pacific solasters have a wide, slightly convex disk on the dorsal side, from which 7-8 rays are rounded on the sides and slightly swollen, although other representatives of this kind of stars usually have more than 10 rays. These are large stars with a ray span of up to 30 cm. The central part of the disk and wide stripes along the rays are dark purple in color and stand out sharply against the general orange-red background. The upper (dorsal) surface of the solasters is covered with contiguous bundles of low needles of various sizes, sitting on a common base - paxillae.
The features of reproduction and biology of the Pacific solasters have not been studied enough. The larvae are lecithotrophic.
Henricia HayashiHenricia hayashi Djakonov, 1961
The systematics of the genus Henricius is very difficult due to the large number of species and the high species variability of these stars, especially the Pacific representatives, so we do not present a photo of a starfish. For the northwest Pacific Ocean 28 species of Henricia were recorded, of which 7 species were recorded for Peter the Great Bay in South Primorye. Henricia live at depths from several tens to several hundred meters.
Henricia - 5-beam, thin stars, with a dorsal surface rough to the touch, characterized by a reticulate, looped microrelief on a relatively small central disc and rounded rays. In rare cases, 6-beam stars are found. Lifetime coloring of Henrcius is usually red, red-brick, orange.
We singled out Henria Hayashi as the shallowest species, living only in the Sea of Japan and found in South Primorye at depths of 25 to 45 meters on rocky bottoms, while other coastal Henria usually occur deeper than 40 m. The span of rays of Henria Hayashi is up to 10 cm.
Henricius' biology features are very interesting, namely, the manifestation of concern for offspring. All species of this genus are viviparous and do not have free-swimming planktonic larvae. Before laying eggs, the female attaches her rays to underwater objects and raises the rest of the rays and the central disk, forming a kind of bell. Eggs are laid in this enclosed space, which develop in tangles near the mouth (or even in the mother's mouth) into a lecithotrophic larval stage, and then into a small star. All this time (usually up to 3 weeks) Henricia-mother maintains her posture and does not take food.
Lysastrosoma anthostictaLysastrosoma anthosticta Fisher, 1922
This 5-ray star is easily distinguished from all others by the “loose”, soft consistency of the body, devoid of the elasticity characteristic of stars, as seen in the photograph. The softness of the dorsal cover is explained by the fact that the plates of the skeleton of lysastrosomes are located very loosely and do not connect with each other into a single shell. The dorsal surface is uneven and bumpy with thin, sparsely located needles. The upper marginal (marginal) plates are widely spaced and connected by chains of small plates. On the lower marginal (marginal) plates on the sides of the rays there are long needles, dressed in a soft sheath, to which a bundle of cruciform pedicillaria is attached.
The span of rays of lysastrosomes reaches 22 cm. The dorsal side is red or dark crimson with a prominent yellow madrepore plate. The underside (ventral) side is light orange.
This species is very widespread in Southern Primorye, meeting in the littoral and at shallow depths on a variety of soils: sand, stony placers, silty substrates, among boulders and in algae thickets. Lysastrosomes are predators that attack mollusks, crustaceans and other echinoderms, including sea urchins. The larvae are planktotrophic.
Dystolasteria pricklyDistolasterias nipon (Doderlein, 1902)
A very large star with a ray span of up to 45 cm, as seen in the photo, often found in Southern Primorye at depths from 2 to 50 m. Usually 5 long strong rays extend from a small central disk, tapering at the ends. The skeletal plates on the dorsal side are arranged in longitudinal rows, and each of them is armed with a strong conical needle. The upper and lower marginal (marginal) plates also bear long blunt needles. All spines are surrounded by a thick ridge of cruciform pedicillaria.
Dystolasteries are very beautiful stars: on the back - velvety black with large bright yellow needles and an orange madrepore plate, and the ventral side is light yellow. Silty soils are preferred. Predators. Spawning occurs in late May - early July. The larvae are planktotrophic.
Letasteria black (photo)Lethasterias fusca Djakonov, 1931
This seaside 5-ray star is easily distinguished by the black or almost black color of the central disk and rays from the dorsal side. There are also dark gray letasteria, and on the rays against a dark background there may be yellowish and whitish spots, sometimes located in the form of bands. The span of the rays reaches 23 cm. The rays are blunt at the ends, and along the middle of their dorsal side there is a row of wide spines, on top of which there are small spines.
Letasteria live on rocky reefs, rocky soils at shallow depths (2-50 m). Rarely found on silted sands with an admixture of pebbles and stones. Juveniles are found on the thalli of macrophyte algae. They lead a predatory lifestyle, attacking medium-sized mollusks, and are often found in oyster beds or on mussel jars. The larvae are planktotrophic.
Aphelasterias japonica Bell, 1881
Distinctive feature of this medium-sized seaside star - narrow constrictions, lacing off from the small central disk long, relatively thick, but easily breaking off rays. The span of the rays, and these stars have 5 of them, is up to 24 cm. The plates of the dorsal skeleton and the spines of the afelasteria are arranged in transverse rows - scallops. The dorsal side is bright crimson, often with an admixture of purple hues. The tips of the needles and the ventral side are whitish.
Japanese letasteria are quite common in the littoral in the area of stone reefs and capes, and are also found on rocky soils to depths of 40-50 m. They are less common on silted sand with an admixture of pebbles and stones, on shell rocks. They make seasonal migrations. They lead a predatory lifestyle, attacking mainly medium-sized mollusks. In Southern Primorye, afelasteria spawn in August-September. The larvae are planktotrophic.
evasteria pricklyEvasterias echinosoma Fisher, 1926
Spiny eusteria is the largest starfish not only in Primorye, but also in all the Far Eastern seas of Russia. The span of the rays of these huge stars reaches 80 cm. There are always 5 rays, they are long, thick, with rounded sides, with short strong blunt needles on the dorsal plates. Plates with needles are arranged along the rays in regular longitudinal rows. Around the needles are bundles of cruciform prehensile pedicillaries. It is very easy to verify their presence and grip - put the outer part of your palm on the star and the pedicillaria will instantly capture the hairs on your arm.
The dorsal side is dark red with a crimson hue. It lives at shallow depths (5-100 m), where it is usually confined to sandy soils with an admixture of pebbles and silt. Rarely found on pure silts or stones. A predator capable of coping with almost all mollusks and other echinoderms. The larvae are planktotrophic.
Evasteria reticulataEvasterias retifera f. tabulata Djakonov, 1938
Reticulated eusteria are smaller representatives of this genus, but they also reach 40 cm in the span of rays. Perhaps these are the most beautiful stars of the Far Eastern seas - turquoise-blue mushroom-shaped needles are located against a crimson background, collected in groups and forming a wide-looped network. The madrepore plate and ventral side are orange. The bizarre and bright patterns on the dorsal surface gave these eusteria the species name - reticulate.
These stars are found from the littoral to small (40 m) depths and are usually confined to sandy soils with an admixture of stones. At low tide, small reticulated evasteria are found among stones and boulders. Predators. The larvae are planktotrophic.
Common Amur StarAsterias amurensis Lutken, 1871
The most common and frequently encountered starfish in the Southern Primorye. Asteria have a wide central disc, from which 5 wide, flattened, with thin, almost sharp, lateral edges, sharpening at the ends of the rays, the span of which in large forms reaches 30 cm, extend. The ventral side is very flat. Dorsal spines small, usually obtusely conical, solitary. The largest of them are sometimes located along the midline of the beam. The color is very variable, ranging from ocher to dark purple, but yellowish-brown, sometimes pinkish-brown forms predominate. They are found in the littoral to depths of 30-40 m, rare deeper. They prefer sandy and rocky soils. On the littoral come across among the stones and thickets of algae. On large thalli of algae, juveniles of asterii form huge clusters (“kindergartens”), covering the surface of macrophytes with small beads. Large asterii are not uncommon in highly polluted bays, where other types of stars no longer survive.
Amur stars are predators that attack mollusks (scallops, oysters, mussels) and other echinoderms, and carrion eaters. In places of large concentrations, cannibalism is often observed. Sometimes, under water, one can observe peculiar “balls” of many asteria, which have stuck around the victim with inverted stomachs.
Of the features of the biology of asterias, their symbiosis (mutually beneficial cohabitation) with polychaete worms (Arctonoe vittata), living in the ambulacral furrows of the star, is interesting. The worm receives the remains of the predator's food, and, in turn, eats numerous epibionts (foulers) from the surface of the star, acting as a cleaner.
In Southern Primorye, the spawning period of Asteria is extended and usually consists of two stages: June-July and September. Amur asterii form dense spawning clusters. The spawning behavior of these stars is interesting. The females rise above the ground on the rays and their reproductive products accumulate between the rays in the form of small (2-3 cm) orange mounds. Males crawl around spawning females, slightly raising the central part and sweeping out their white gonads. Then the stars of both sexes begin to crawl in the area of spawning grounds, simultaneously mixing the sexual products and protecting them from juvenile fish and various crustaceans. This type of behavior can also be called care for offspring. Asterium larvae are planktotrophic.
And finally, how a starfish walks.
It turns out that there are stars not only in the sky, but also under water. And it is worth noting that the underwater stars are much more diverse and beautiful than the heavenly ones. Not only that, they are still alive! Yes, the starfish is an animal. All types of starfish belong to the class of invertebrates and are representative of the type: "echinoderms".
The structure of starfish
Based on the name, this creature has a structure similar to the generally accepted image of a star - i.e. five-pointed figure. The body structure system of this animal in the scientific world was called "ambulacral".
Its essence lies in the fact that inside the starfish has channels and cavities in which water is located. By pumping fluid from one part of the body to another, the starfish makes movements. Except interesting shape the animal has prickly thorns on its body. The mouth is in the center of the lower body (abdomen).
The starfish breathes with the help of skin outgrowths, because nature did not provide this creature with gills and lungs. Because of this respiratory feature, the animal suffers greatly when there is not enough oxygen in the water.
On the other hand, the starfish boasts a pretty good digestive system, consisting of two gastric bags, and an excellent ability to regenerate.
In size, these creatures are different - from the smallest (1.5 cm) to decent (90 cm). A starfish lives for 20 years, and sometimes more.
Distribution on the planet
These wonderful inhabitants of our planet inhabit almost all the seas and oceans. They can only live in salt water. Starfish live even in northern waters, despite low temperatures. Although in warm seas there are many more of them.
Lifestyle
Mainly, the starfish is a shallow-water animal, although among the representatives of this species there are also deep sea dwellers. Sometimes starfish are found at depths greater than 9,000 meters.
Animals move along the bottom, very slowly - only 10 centimeters per minute. If necessary, the starfish can “add speed” and “accelerate” up to 30 centimeters per minute.
Diet
Despite the natural beauty and attractiveness, the starfish is a real predator. It feeds on worms, molluscs, and small invertebrates. In addition, some stars may eat plankton and detritus.
How starfish reproduce
Representatives of this species of invertebrates are mostly dioecious. Their sex glands are located at the base of their legs (rays). Some starfish may have sex glands of both sexes, and sometimes (in certain types) and can even change gender (from male to female).
Mating occurs by connecting the rays. During this process, male germ cells and eggs are swept into the water. As a result of fertilization, after a certain period of time, small larvae are born.
A feature of some representatives of starfish is the ability to reproduce asexually, namely, by division! The body of one star is divided into two parts, and each of them begins to develop and grow independently.
Even if you take this animal and divide it into parts with your hands, it will also multiply. Only due to slow growth, one leg (from which the development of a new individual will begin) will for a long time longer than the rest.
The name of this starfish speaks for itself - elegant fromia (Fromia elegans) Do these beautiful underwater creatures have enemies?
Sure there are, but not many. They don't really want large predators get hurt on the prickly thorns of a star.
And the stars themselves, seeing the enemy, try to dig deeper into the sand as soon as possible. Among natural enemies starfish are dominated by gulls and sea otters.
The use of starfish by humans
Some species of these invertebrates are eaten by the Chinese, although not often.
More than any interest for humans, except for aesthetic, these animals do not represent. Perhaps they were created by nature in order to simply admire them and get a lot of positive emotions from this.
Asteria starfish (Asterias rubens) pulls its hand towards a clam
