They raise many questions, among which the following are of particular interest: “What does a starfish eat?”, “For whom does it pose a mortal threat?”
Stars on the seabed
These extraordinary decorations of the seabed have existed on the planet for quite a long time. They appeared about 450 million years ago. There are up to 1600 types of stars. These animals inhabit almost all seas and oceans of the earth, the water of which is quite salty. Stars do not tolerate desalinated water; they cannot be found in the Azov and Caspian Seas.
Animals can have rays from 4 to 50, sizes range from a few centimeters to a meter. The lifespan is about 20 years.
The sea inhabitants do not have a brain, but on every ray there is an eye. The organs of vision resemble insects or crustaceans and distinguish between light and shadow well. Many eyes help animals hunt successfully.
Stars breathe almost through their skin, so it is very important for them to have a sufficient amount of oxygen in the water. Although some species can live at decent depths of the ocean.
Structural features
It is interesting how starfish reproduce and feed. Biology classifies them as invertebrate echinoderms. The starfish does not have blood as such. Instead, the star's heart pumps sea water enriched with certain microelements through its vessels. Pumping water not only saturates the animal's cells, but also by forcing fluid into one place or another helps the star move.
Starfish have a ray structure of the skeleton - rays extend from the central part. The skeleton of sea beauties is unusual. It consists of calcite and develops inside a small star from almost a few calcareous cells. What and how starfish feed largely depends on the characteristics of their structure.
These echinoderms have special pedicellaria on their tentacles in the form of tweezers at each tip of the outgrowth. With their help, the stars hunt and clean their skins from debris clogged between the needles.
Cunning hunters
Many people are interested in how starfish eat. A brief description of the structure of their digestive system can be found below. These amazing beauties create the impression of complete security. In fact, they are sea predators, voracious and insatiable. Their only drawback is their low speed. Therefore, they prefer a stationary delicacy - mollusk shells. The starfish eats scallops with pleasure, and is not averse to eating sea urchins, sea cucumbers, and even fish that carelessly swim too close.
The fact is that the starfish has practically two stomachs, one of which can turn outward. An unwary prey, captured by the pedicellariae, is transferred to the mouth opening in the center of the rays, then the stomach is thrown over it like a net. After this, the hunter can release the prey and slowly digest it. For some time, the fish even drags its executioner along with it, but the victim can no longer escape. Everything that a starfish eats is easily digested in its stomach.
She acts somewhat differently with shells: she slowly approaches the dish she likes, entwines the shell with her rays, places her mouth opening opposite the slit of the shell and begins to move the shells apart.
As soon as even a small gap appears, the external stomach is immediately pushed into it. Now the sea gourmet calmly digests the owner of the shell, turning the mollusk into a jelly-like substance. This fate awaits any eaten victim, no matter whether the starfish feeds on a scallop or a small fish.
Features of the structure of the digestive system
The predator does not have any devices for capturing prey. The mouth, surrounded by a ring lip, connects to the stomach. This organ occupies the entire interior of the disc and is highly flexible. A gap of 0.1 mm is enough to penetrate the shell doors. In the center of the aboral side, a narrow, short intestine opens, extending from the stomach. What a starfish eats largely depends on the unusual structure of its digestive system.
Love of the stars at the bottom of the ocean
Most starfish are heterosexual. During love games, individuals are so busy with each other that they stop hunting and are forced to fast. But this is not fatal, because in one of the stomachs these cunning creatures try to deposit nutrients in advance for the entire duration of mating.
The gonads are located in stars near the base of the rays. When mating, the female and male individuals connect the rays, as if merging in a tender embrace. Most often, eggs and male reproductive cells end up in sea water, where fertilization occurs.
If there is a shortage of certain individuals, stars can change sex to maintain the population in a certain area.
These eggs are most often left to their own devices until the larvae hatch. But some stars turn out to be caring parents: they carry eggs and then larvae on their backs. For this purpose, in certain species of starfish, during mating, special sacs for eggs appear on their backs, which are well washed with water. There she can remain with the parent until the larvae appear.
Reproduction by division
A completely extraordinary ability of starfish is reproduction by fission. The ability to grow a new ray arm exists in almost all animals of this species. A star grabbed by a beam by a predator can throw it away like a lizard's tail. And after a while, grow a new one.
Moreover, if a small particle of the central part remains on the beam, after a certain time a full-fledged starfish will grow from it. Therefore, it is impossible to destroy these predators by cutting them into pieces.
Who are starfish afraid of?
Representatives of this class have few enemies. Nobody wants to mess with the poisonous needles of sea celestials. Animals are also able to secrete odorous substances to scare away particularly voracious predators. In case of danger, the star can bury itself in silt or sand, becoming almost invisible.
Among those who feed on starfish in nature, large seabirds predominate. On the shores of warm seas they become prey for seagulls. In the Pacific Ocean, cheerful sea otters are not averse to feasting on the star.
Predators harm underwater plantations of oysters and scallops - what the starfish eats. Attempts to kill animals by cutting them into pieces led to an increase in the population. Then they began to fight them, bringing the stars ashore and boiling them in boiling water. But there was nowhere to use these remains. There have been attempts to make fertilizer from animals that also repels pests. But this method was not widely used.
Sea stars- These are very unusual animals that live in the seas and oceans. They are invertebrates, belong to the phylum echinoderms and are very similar to stars, as they have rays diverging in different directions. Most often, the sea star has five rays, but there are species with three, four and six rays. The color of the body is often very bright and varied; on the surface there are special hard plates with needles or spines. The sizes of stars vary greatly and can range from 2 cm to 100 cm, but most stars have a diameter of about 20 cm.
Spreading
Starfish are widely distributed around the globe. They can be found in all oceans and seas and in all climatic zones, but there are more starfish in warm waters than in cold ones, and they are not found at all in fresh waters.
These animals prefer a bottom lifestyle, often live in shallow water, but can also live at depth, but not deeper than 8.5 km.
Now on earth there are 1.6 thousand species of starfish.
Nutrition
Almost all starfish are predators. They mainly feed on marine invertebrates - worms, mollusks, sponges, barnacles, corals and others. Some deep-sea starfish feed on the mud they find on the bottom.
The digestive system of starfish is quite unique. Their mouth opening is located on the ventral side, and two stomachs extend from it. One stomach has the ability to turn outward and envelop the victim, and the second stomach has ten processes that are located inside the rays of the starfish. This unusual digestive system allows the star to eat prey that is larger than itself.
Lifestyle
Starfish are slow, sedentary animals. They usually crawl lazily along the bottom, lie still, or may climb rocks and corals in search of prey. Their movement speed is very low - 10-30 cm per minute. Stars are considered sedentary animals. As a rule, they move no further than 0.5 km from their usual place of residence.
In their development, stars go through several stages of development. From the eggs that adults throw into the water, larvae are first formed and then they gradually turn into an adult starfish. Some species of starfish carry larvae in special brood pouches on their bodies.
Starfish can live 20 years or more.
- Starfish don't have a brain.
- Instead of eyes, starfish have light-sensitive cells located at the tips of their rays.
- Starfish are capable of regeneration - from a detached ray, a new star can develop.
Brief information about starfish.
When you see a starfish for the first time, the first thing that comes to your mind is that it’s an ordinary souvenir, but in fact it is a living creature that looks like a star. With its way of life, this entity seems to ignore all the usual laws of biology - having neither blood nor brain, stars have unique eyes and can digest food outside their body.
External features of starfish
Starfish are invertebrate, nearly symmetrical animals that are found in all oceans. They appeared approximately 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 1,800 species of starfish. Each species has its own characteristics, but all representatives are united by a correct symmetrical shape and a number of external features that prevent them from being confused with any other species.
Typically, stars have five or six rays that emanate from the center of the disk. The record number of rays that zoologists have recorded is 50; at great depths, representatives of the species with 10-15 rays are found. In starfish, the body length can reach one meter, but the most characteristic size is 15-25 centimeters. Large stars can weigh 5 kilograms; they are also called “solar stars”. These types of animals are more powerful; they have enough power to tear apart the shells of crustaceans. They hunt their prey and can even pursue it for a long time.
Starfish have a rough or smooth surface and may be covered with ridges or sharp, poisonous spines. Some of the representatives of the starfish family have very bright colors and are extremely 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 close to the surface, while pale ones, as a rule, live at great depths.
Feeding starfish
As for the nutrition of sea stars, their diet is quite varied - they do not disdain to feast on carrion, they feed on sea urchins, which are several times their size, and crabs, and can even attack small fish. Moving along the bottom, they dig small holes and there they wait for their prey, which inadvertently approaches the mouth opening of the star. The feeding process itself is very interesting: the star drags its stomach out and envelops its victim in it. During the eating process, special enzymes are released that help digest food not inside the star, but outside.
Starfish have a very flexible stomach; it only needs 0.1 mm to penetrate the gap. It is for this reason that mollusks only need to open their valves a little, and the starfish will already envelop them with its stomach and eat it. The eating process 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 scientific videos, the starfish regrows lost organs and is completely restored if at least half of the disk or lost ray is present. There are scientific cases where a fallen limb completely restored the entire disc. There are also species of starfish that reproduce this way - by fission.
The species also has sexual reproduction. Males and females release their eggs into the water and fertilization occurs outside the body. No matter how strange it may sound, 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 to the bottom and lead an independent life. Some species of stars hatch larvae in their stomach or under a plate. But, this is rare; in most cases, fertilization occurs outside the female’s body.
Internal skeleton and muscles
Initially, it may seem that in the absence of olfactory organs and a brain, these are primitive animals, but such simplicity is very deceptive. As the scientific video shows, starfish have a skeleton. Of course, skeleton stars do not consist of a backbone, but they have calcareous plates connected to each other in an openwork system.
In young organisms this openwork system is not visible, but with age the skin wears off and the skeleton begins to appear outward. It is the protrusion of the skeletal plates that makes the starfish spiny. Some calcareous plates that protrude outward merge together and create the appearance of tentacles. With their help, starfish clean the outer part of their plate from sand and various debris. After a starfish dies, its skeleton crumbles and all that remains is dust. Some sea stars have poisonous tentacles and serve as an additional means of hunting small fish and crustaceans.
As for the muscular system, as the scientific 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 animal. All the muscle can do is lift the beam upward.
Some of the starfish can even climb up algae; such movement is achieved thanks to the ambulacral system of the body. The system consists of cavities and channels that are filled with liquid, which the star can distill into different parts of its body and thus move. The main feature of this system is that it provides small legs on the underside of the star plane. The tiny outgrowths move individually, but in most cases all movements are coordinated and rhythmic. Thanks to these small legs, the starfish can rear up, stick to vertical planes, and even tear the shell of a mollusk with two rays.
Sense organs of starfish
Starfish completely lack all sense organs, except for the eyes, of course. The eyes are located at the tip of each ray. Starfish do not distinguish objects and colors; their eyes are very primitive, so they only recognize light and darkness.
An analogue of the sense of smell in these animals is the ability to capture chemical substances that are present in the water with their body. Animals move not using their eyes, but using their sense of touch. They feel their way in the sand, and with the help of the same sense of touch, they understand who they encountered on the road, a predator or prey. Note that all this happens in the absence of a brain. Starfish brains are replaced by tightly interconnected nerve cells. It is very surprising 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 been caught in nets are freed much faster than those that have gotten there for the first time.
Distribution area of starfish
Starfish do not tolerate fresh water, so they are found only in seas and oceans where there is salt water. They move very slowly, on average 10 centimeters per minute. They can climb rocks, seaweed and coral. A very interesting fact is that, unlike turtles, which, having fallen on their backs, cannot turn over on their own, starfish immediately return to their usual position.
This species of animal can be safely classified as sedentary; in its entire life it is unlikely that it moves further than 500 meters from its birth. In their usual habitat, starfish have virtually no enemies. The spiny structure of the body repels large predators, so they lead a completely quiet life, but can sometimes be caught in the mouths of seagulls and sea otters, which mistake them for fish.
People have noticed colorful inhabitants of the deep sea for a long time, but starfish have no economic use, only in China they are occasionally eaten. Starfish are very sensitive to high temperatures and can be killed by simply pouring boiling water on them. Many starfish are poisonous, so it is not recommended to pick them up with bare hands. This once again proves how changeable nature can be - such a beautiful and at first glance harmless creature can take the life of a large person in one minute.
You can even see these and other inhabitants of the underwater world in person!
Starfish are one of the most beautiful and mysterious sea creatures. These animals add extraordinary beauty to the seas and oceans. Such unusual sea creatures first appeared more than 450 million years ago.
Starfish belong to the class of invertebrates and the phylum Echinodermata. They are very diverse not only in their colors, but also in shape. Today there are more than 1,600 species of starfish. Their close relatives are snaketails, luxurious sea lilies, sea cucumbers, and also extraordinary sea urchins.
The main distinguishing feature of starfish from their relatives is their body shape. The body has the shape of a star, which is divided into 5 symmetrical sectors. However, among these graceful animals there are organisms that are endowed big amount sectors. In some individuals, their number can vary from 6 to 12, and sometimes even from 45 to 50.
The colors of these amazing sea creatures include almost the entire color gamut, but, in most cases, you can find shades of red, less often brown, blue, purple, pink, yellow and black. There are also pale starfish, but they usually live on the bottom of the sea or ocean, while bright ones live in shallow water.
At first, starfish may seem like primitive creatures, because they lack sensory organs, a brain, and also poorly separated internal organs, but such simplicity is nothing more than deception.
It is important to note that this type of invertebrate has an internal skeleton. Despite the fact that sea stars do not have a backbone, they have a huge number of calcareous plates that are connected to each other together.
In a young individual, the skeletal components are hidden under the skin, but after a certain period of time the skin wears off and the spines become visible from the outside. These spines give starfish their prickly appearance.
There is also another component that affects the appearance of these beautiful sea creatures - pedicillaria. Pedicillaria are modified needles, similar to tiny tweezers. They play an important role in the life of the starfish. Thanks to tweezers, they clean the upper side of their body from various debris and sand.
Starfish have an underdeveloped muscular system. However, they have a special system - ambulacral, which consists of cavities and channels woven together. Thanks to this system, starfish pump liquid from one part to another. When pumping liquid, parts of its body begin to wriggle and move.
It is important to note that these beautiful animals still have sense organs. These include the eyes located at the ends of each sector. The eyes are very primitive and can only distinguish between light and darkness; these luxurious sea creatures are unable to see objects. They only detect chemicals, but each of them senses them differently. Starfish have a well-developed sense of touch, which tells them whether they are encountering a prey or a predator.
They also have a well-developed digestive system. The mouth of these unusually beautiful animals is located in the middle of the disc on the underside, and the small anus is located on the dorsal side of the body. The stomach of sea stars is endowed with outgrowths in which food reserves are accumulated in case of starvation. And starvation occurs regularly in starfish, because during the breeding season they stop eating food. The stomach of such an animal can stretch like rubber, taking various shapes. Thanks to this stretching of the stomach, sea beauties are able to digest prey whose parameters exceed their own size several times. There is a known fact when a species of starfish, Luidia, ate a huge sea urchin to such an extent that after eating such food, she died because she could not get rid of its remains.
Sea beauties are found in almost all seas and oceans. However, in warm waters the variety of starfish is much higher than in cold waters. Most of them live in shallow water, but there are also those that prefer to be in depth.
Initially, starfish may seem helpless, but this is far from the case. They are formidable predators. These delightful sea creatures are insatiable and never miss an opportunity to eat. The exception is the breeding season. Silt, or rather their mined particles, feed only on those species that live on the bottom of the sea or ocean. Conditionally, “non-predators” include culcites, which feed on growths on corals. The remaining species hunt for other prey.
Most starfish are unpretentious eaters; they eat everything they can hold with their rays until their stomach stretches, not even disdaining carrion. Certain species feed only on a different type of food: corals, gastropods and sponges.
The favorite food of sea stars are sedentary animals - bivalves and sea urchins. They chase the sea urchin crawling, after they have caught up with it, they begin to eat it with their mouth. Bivalve mollusks have shells whose valves close very tightly in case of any danger. For this reason, these shellfish are treated differently by starfish. At first, the starfish clings with its rays to the shell flaps and only after that begins to open them.
Like most representatives of fauna, starfish are heterosexual. But there are also species that have both female and male genital organs at the same time. They are located at the base of the rays in pairs.
Reproduction of sea stars occurs both sexually and asexually. Basically, such reproduction occurs only in multirayed species. The starfish's body is divided into two parts, after which each of them multiplies the rays that are missing. In all other animals, asexual reproduction is possible only in case of recovery from damage to the body. One beam is enough for regeneration, but a mandatory element for restoration is the presence of a piece of the central disk.
Typically, these amazing sea animals have few enemies because the spines, which can contain poison, repel larger predators. Moreover, starfish, sensing approaching danger, bury themselves in the sand so as not to attract the attention of a predator.
People have noticed these unusual, original animals in shallow water for a very long time. However, starfish did not arouse any economic interest for them. Only in China, some people eat them, but at the same time, no one dared to feed their pets with starfish, since after eating the delicacy, the pets could die. This is most likely due to toxins that certain species accumulate from eating various corals and poisonous shellfish. But with the prosperity of the maritime economy, starfish began to be considered enemies. It later turned out that these animals very often ate bait intended in crab traps, and also made invasions on plantations where scallops and oysters were bred. At one time, they tried to eradicate these sea predators by cutting them into pieces. But this only increased their number, because from each piece a new starfish appeared. Over time, they learned to catch them using special trawls, after which the starfish were killed with boiling water.
Sea stars
classis Asteroidea de Blainville, 1830
These echinoderms usually have a flattened body, smoothly turning 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, reminiscent of tentacles. Unlike lilies, the movie star's mouth and ambulacral grooves are located on the lower surface of the body, facing the substrate. 
In 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 the ambulacral grooves. 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 the pedicellaria is a group of a number of elongated “bones” that work like scissors or forceps. 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 movie stars are predators and corpse eaters; stars are known to be detritivores and filter feeders. Cannibalism is also common. When capturing a large prey, the star's stomach is capable of turning outward from the mouth opening and enveloping the prey.
The larvae of movie stars are called bipinnaria and brachiolaria, but there are stars with direct development, capable of bearing their young and caring for their offspring. Larvae that are able to feed during their own development in plankton are called planktotrophic, while non-feeding planktonic larvae are called lecithotrophic larvae.
There are now about 1,500 known species of sea movie stars, most of which are inhabitants of tropical seas.
According to our data, 25 species of movie stars live in the waters of Southern Primorye. Let's talk about the most typical and frequently encountered representatives of this class of echinoderms.
Ludia two-needleLuidia quinaria Martens, 1865 bispinosa Djakonov, 1952
This star has a strongly flattened body with 5 long, narrow rays, pointed at the ends. The span of the rays of the luidia reaches 30 cm. On the superficial (dorsal) side, the central disk and rays of the 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 smooth and covered with square-shaped paxillae - groups of small needles sitting on one rod. On the sides of the rays there are large flattened spines and small spines extending from the lower marginal (marginal) plates.
They live on muddy, silty or sandy soils at depths from 3 to 100 m. Luidia have planktotrophic larvae.
Patiria combPatiria pectinifera (Mueller et Troschel, 1842)
This star has a wide, flattened disk and very short, wide rays that are pointed at the ends. The dorsal side is somewhat convex, and the ventral side is completely flat. There are usually 5 rays, although 4, 6 and even 7-rayed pathiria are found. The ray span of the largest specimens reaches 18 cm. The color of the pathiria 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 pathiria is covered with plates overlapping each other like tiles, the free edges of which always face the center of the disk. Patiria received its specific name for the combs of needles located on the ventral side, connected at the base by a soft membrane.
Patiria comb is a low-boreal-subtropical species, found mainly in the regions of Southern Primorye. These stars are very common in the littoral zone among stones and on rocky ground. On sandy, rocky and silty soils, pathiria 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 zoster and phyllopadex algae. Patiria is a predator that prefers to attack small mollusks.
In the waters of Southern Primorye, patiriyas spawn in the second half of August and early September. Patirium larvae are planktotrophic.
Solaster pacificSolaster pacificus Djakonov, 1938
These cold-water stars prefer greater depths and are found in Southern Primorye, as a rule, deeper than 60-70 m.
Pacific solasters have a wide disk, slightly convex on the dorsal side, from which 7-8 rays, rounded on the sides and slightly swollen, extend, although other representatives of this genus 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 closely spaced bunches of low needles of different sizes, sitting on common bases – paxillae.
The reproductive characteristics and biology of Pacific solasters have not been sufficiently studied. The larvae are lecithotrophic.
Henricia HayashiHenricia hayashi Djakonov, 1961
The taxonomy of the genus Henrici is very difficult due to large quantity species and great species variability of these stars, especially Pacific representatives, so we do not present a photo of the starfish. For the northwestern part of the Pacific Ocean, 28 species of Henricia have been recorded, of which 7 species have been recorded for the Peter the Great Bay in Southern Primorye. Henricias live at depths from several tens to several hundred meters.
Henricia are 5-rayed, thin stars, with a dorsal surface rough to the touch, characterized by a reticulated, looped microrelief on a relatively small central disk and rounded rays. In rare cases, 6-rayed stars are found. Lifetime coloration of Henricia is usually red, red brick, or orange.
We identified Henricia Hayashi as the shallowest-water species, living only in the Sea of Japan and found in Southern Primorye at depths of 25 to 45 meters on rocky soils, while other coastal Henricias are usually found deeper than 40 m. The ray span of Henricia Hayashi is up to 10 cm.
The peculiarities of the biology of Henricia are very interesting, namely, the manifestation of care for the 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 something like a bell. Eggs are laid in this enclosed space and develop in balls 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), mother Henricia maintains her position and does not eat.
Lysastrosoma antistictaLysastrosoma anthosticta Fisher, 1922
This 5-rayed star is easily distinguishable from all others by the “loose”, soft consistency of the body, devoid of the elasticity characteristic of stars, as can be seen in the photograph. The softness of the dorsal cover is explained by the fact that the lysastrosome skeleton plates are located very loosely and are not connected to each other into a single shell. The dorsal surface is uneven and lumpy with thin, sparsely spaced spines. 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, covered with a soft sheath, to which a bunch of cruciform pedicillariae is attached.
The span of the lysastrosome rays reaches 22 cm. The dorsal side is red or dark crimson with a prominent yellow madrepore plate. The lower (ventral) side is light orange.
This species is very widespread in Southern Primorye, occurring in the littoral zone and at shallow depths on a variety of soils: sand, rocky deposits, muddy substrates, among boulders and in algae thickets. Lysastrosomes are predators that attack mollusks, crustaceans and other echinoderms, including sea urchins. The larvae are planktotrophic.
Distolasteria causticusDistolasterias nipon (Doderlein, 1902)
A very large star with a ray span of up to 45 cm, as can be seen in the photo, often found in Southern Primorye at depths from 2 to 50 m. Usually 5 long strong rays extend from the 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 plates also bear long, blunt spines. All needles are surrounded by a thick ridge of cruciform pedicillariae.
Distolasteria are very beautiful stars: on the back they are velvety black with large bright yellow needles and an orange madrepore plate, and the ventral side is light yellow. They prefer silty soils. Predators. Spawning occurs in late May - early July. The larvae are planktotrophic.
Letasteria black (photo)Lethasterias fusca Djakonov, 1931
This seaside 5-rayed star is easily distinguished by the black or almost black color of the central disk and rays on the dorsal side. Dark gray letasteria are also found, and on the rays against a dark background there may be yellowish and whitish spots, sometimes arranged 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 needles, at the top of which there are small spines.
Letasteria live on rocky reefs and rocky soils at shallow depths (2-50 m). Less common on silty sands mixed with pebbles and stones. Juveniles are found on thalli of macrophyte algae. They lead a predatory lifestyle, attacking small shellfish, and are often found in oyster beds or on mussel banks. The larvae are planktotrophic.
Aphelasterias japonica Bell, 1881
A distinctive feature of this medium-sized seaside star is narrow constrictions that lace long, relatively thick, but easily broken off rays from the small central disk. The scope 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 aphelasteria are arranged in transverse rows - combs. The dorsal side is bright crimson, often mixed with purple hues. The tips of the needles and the ventral side are whitish.
Japanese letasteria are quite common in the littoral zone 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 mixed with pebbles and stones, and on shell rocks. They make seasonal migrations. They lead a predatory lifestyle, attacking mainly small mollusks. In Southern Primorye, afelasteria spawn in August-September. The larvae are planktotrophic.
Euasteria spinosaEvasterias echinosoma Fisher, 1926
Spiny elasteria 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. The plates with needles are located along the rays in regular longitudinal rows. Around the needles are bundles of cruciform grasping pedicillariae. It is very easy to verify their presence and grip - place the outer part of your palm on the star and the pedicillaria will instantly grab the hairs on your hand.
The dorsal side is dark red with a crimson tint. It lives at shallow depths (5-100 m), where it is usually confined to sandy soils mixed with pebbles and silt. Less common on clean mud or rocks. A predator that can cope with almost all mollusks and other echinoderms. The larvae are planktotrophic.
Evasteria reticularisEvasterias retifera f. tabulata Djakonov, 1938
Reticulate easteria are smaller representatives of this genus, but their ray span reaches 40 cm. Perhaps these are the most beautiful stars of the Far Eastern seas - against a crimson background there are turquoise-blue mushroom-shaped needles, collected in groups and forming a wide-loop network. The madrepore plate and ventral side are orange. Bizarre and bright patterns on the dorsal surface gave these eusteria their species name – reticulata.
These stars are found from the littoral zone to shallow (40 m) depths and are usually confined to sandy soils mixed with stones. At low tide, medium-sized reticulated elasteria 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 Southern Primorye. Asteria have a wide central disk, from which extend 5 wide, flattened, with thin, almost sharp, lateral edges, pointed at the ends of the rays, the span of which in large forms reaches 30 cm. The ventral side is very flat. The dorsal needles are small, usually bluntly cone-shaped, single. 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 zone to depths of 30-40 m, and are rare deeper. They prefer sandy and rocky soils. In the littoral zone they are found among stones and algae thickets. On large algae thalli, juvenile asteria form huge accumulations (“kindergartens”), covering the surface of macrophytes with small beads. Large asteria are not uncommon in bays that are highly polluted by humans, where other types of stars no longer survive.
Amur stars are predators that attack mollusks (scallops, oysters, mussels) and other echinoderms, and are carrion eaters. In places of large concentrations, cannibalism is often observed. Sometimes under water you can observe peculiar “balls” of many asteria, clinging to the victim with their inverted stomachs.
Of the peculiarities of the biology of asteria, their symbiosis (mutually beneficial cohabitation) with polychaete arctonoe worms (Arctonoe vittata), living in the ambulacral grooves of the star, is interesting. The worm receives the remains of the predator's food, and in turn eats numerous epibionts (fouling organisms) 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 asteria form dense spawning aggregations. The spawning behavior of these stars is interesting. Females rise above the ground on the rays and their reproductive products accumulate between the rays in the form of small (2-3 cm) orangish mounds. The males crawl around the spawning females, slightly lifting the central part and sweeping out their white reproductive products. Then the stars of both sexes begin to crawl in the spawning areas, simultaneously mixing the sexual products and protecting them from juvenile fish and various crustaceans. This type of behavior can also be called caring for offspring. The larva of Asteria is planktotrophic.
And finally, how does a starfish walk?
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