What do you know about starfish? Beautiful and unusual creatures, with many interesting facts from their life - in our selection. Currently, about two thousand species of starfish are known.

Starfish do not have a brain or blood - to obtain nutrients, oxygen and other important fluids, the starfish pumps sea water through its body. It is the resulting water that is distributed throughout the body and forms the “water-vascular system.”

On each arm of a starfish, mistaken for tentacles, there are about 15 thousand tiny suckers that help the starfish move.

A starfish is not a fish, but an invertebrate animal.
Starfish are true predators. They are capable of attacking 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, which is distributed throughout the Indo-Pacific Ocean, is covered in venomous spines. Growing to almost half a meter in length, these creatures become dangerous not only for coral reefs, but also for divers and swimmers.

Starfish can 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 there are rays; at the tip of the rays there is an eye, which looks like a red spot. They don’t see very well, of course, but at least they can distinguish between darkness and light.

Even though starfish live underwater, they do not have gills.

Although the appearance of most starfish corresponds to their name, sometimes unusual individuals with bizarre shapes are found. For example, starfish may have a sun-shaped shape, multiple 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 their weight can reach 5 kilograms. Solar stars are more active than their relatives, and are able to rapidly pursue their prey, and, having incredible strength, simply tear apart the shell of mollusks and crustaceans.

The feeding method that allows the starfish to eat prey much larger than the mouth opening is as follows - since the starfish's mouth is on the underside of its body, the star, having grabbed the prey, wraps its strong arms around it, and then with a strong push places it under itself, and then pushes it into the stomach.

They are also some of the most ancient inhabitants of the Earth. Starfish are about 250 million years old.

Stars move using hundreds of tubes that are attached to the surface and then move in waves.

Starfish live at various depths, up to ten kilometers

In the last few years, starfish have begun to actively reproduce. This creates a problem, because each individual has an excessive appetite and consumes about 6 square meters corals 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 - every year sea stars collectively destroy about 2% of the Earth's carbon dioxide, and this is an extremely large figure for the entire planet.

Another useful role of starfish is to clean the seabed of carrion, weak and sick creatures of the seabed, as well as the remains of dead oceanic organisms.

Starfish go through five stages of growth before becoming adults - during the first month, stars are free-swimming and jellyfish-like, they are small, almost invisible to the eye and tiny plants and animals of the ocean.

Although most sea stars are not poisonous, a large star called the acanthaster or crown of thorns is dangerous to humans. The pricks of its needles bring burning pain to a person - if the needle gets stuck in the skin, then it breaks off from the star’s body and begins to infect the person’s blood with poisonous secretions.

Interesting fact - if you cut off one of the arms of a starfish or all at once without damaging central part bodies, they will gradually grow back.

Although starfish are brightly colored and harmless appearance, don't be fooled by this.

Starfish predators

Many of them are predators, feeding on mollusks, crustaceans and sea urchins. With a small central disk, excluding tentacles, they are capable of eating prey much larger than themselves. And quite in an original way. Having blocked the mollusk with the help of processes, they turn their stomach inside the shell through the mouth opening and digest the prey on the spot.

Like other echinoderms, the star's shell consists of calcium plates connected to each other by muscle fibers. Stars are masters of regeneration. Unlike earthworm, cut in half, who does not actually regenerate, but slowly dies, the star is capable of performing miracles. The missing shoot grows to normal length in just a few weeks. And at the top of the lost piece of the stump, four new small processes appear, which develop into a full-fledged nova. This system is so effective that some species of starfish use it to reproduce non-sexually.

Of all the types of Mediterranean stars, the champion in restoring missing body parts is considered to be the red star (Echinaster sepositus), which comes not only with the classic five, but even with eight rays.

The spiny starfish, or martasteria, is a native of the Old World. It can only be found on the European Atlantic coast and in the seas adjacent to the ocean. This is a large starfish, usually growing up to forty centimeters, although it can reach seventy centimeters, with a small central disk and five thin, tapering rays. Each ray has three rows of conical whitish spines, often with purple tips. The color of the martasteria can be brown or greenish-gray with yellow, red or purple ray tips. This echinoderm is widespread from Iceland to South Africa. Like many other stars, it is a predator. It feeds mainly on mollusks and other invertebrates.

Sometimes it is also called the blue spiky star or white star. The background color is cream with a bluish tint, with brown spots scattered throughout. This star departs from the five-rayed tradition and has from 6 to 12 rays. Most often seven. Can grow up to 20 cm, but, as a rule, 10. Lives in shallow waters Atlantic Ocean And Mediterranean Sea without falling below 50 meters. The star is a predator, feeding, like its larger sister, on echinoderms and bivalves.

The seven-rayed star has an orange-brown color, a small central disk and seven rays of almost the same width along the entire length, slightly tapering towards the ends. Along the edges of the rays there is a fringe of white spikes. Distributed from Norway to Cape Verde, it can also be found in the Mediterranean Sea. Lives on seabed at a depth of up to four hundred meters.

It is a predator that feeds on other echinoderms such as brittle stars and sea urchins. This animal moves very quickly compared to other stars. It lifts itself on the tips of its rays, moving in such a position as it hunts prey. A star attacks from above. Moreover, it can even catch echinoderms, which are much larger than its mouth opening. If necessary, the star can “tear” his mouth to swallow big piece. In this way, it eats brittle stars with a diameter of 25 cm.

Red star (Echinaster sepositus)

The color of the red star is not quite red. It's more orange-red. Although it usually grows up to twenty centimeters, its central disk is small. The surface is dotted with small spines.

Starfish look very beautiful while they are in the water.

When taken out of the water, they lose their colors when they die, turning into gray lime skeletons. If you want to take real beauty with you, then it is better to get a waterproof camera.

Sea stars found at different depths; Some species live at depths of thousands of meters, others near the very shores, sometimes remaining at low tide for several hours without water. Starfish are hardy in many respects, but (like other echinoderms) are extremely sensitive to the degree of salinity of the water, requiring water at normal ocean salinity (about 3%). Therefore, they are absent in the Black and Baltic Seas.

The stars can reach large sizes, up to 70 cm or more from the end of one beam to the end of the beam opposite it; often brightly and variegatedly colored. The number of species is more than 1700.

Structure and physiology. The body of starfish has the shape of a five-rayed star, in which a central disk and five rays, or arms, are distinguished. However, there are stars that have more than five rays: with six ( Hexaster) or with nine, eleven, thirteen rays or more. Especially big number stars from the family have rays (more than 30) Brisingidae.

For ease of orientation in the body of echinoderms, there are, firstly, lines running from the center to the end of the rays, called radii or radial lines; secondly, lines ending at the edge of the disk between adjacent rays, which are designated as interradii or interradial lines.

The body of the star is flattened along the axis of symmetry. The mouth is placed in the center of one of the flat sides (oral side), and the powder (aboral side) is placed in the center of the other. The animal crawls along the bottom with its mouth down. Crawling is accomplished with the help of special processes, ambulacral legs, located at the bottom of the ambulacral groove on the lower (oral) side of each ray.

The body wall consists of a single-layer usually ciliated epithelium and a layer of underlying connective tissue; Under the connective tissue lies the peritoneal epithelium, which limits the secondary body cavity, or whole, in which all the internal organs are located.

In the subcutaneous connective tissue, the calcareous skeleton develops, first in the form of microscopic bodies, which later merge into larger and regularly located plates. The skeleton is more developed on the oral, oral, side of the body. Each ray has two rows of ambulacral plates, which are connected to each other in pairs and cover, like a gable roof, the ambulacral groove of the oral (oral) side.

The skeleton of the aboral side is represented for the most part only by numerous narrow calcareous crossbars. Among them, in one of the interradii of the disk, a rather large, sometimes differently colored than the rest of the disk, madrepore plate, pierced by numerous small holes, stands out. Spines, small calcareous needles, etc. extend from the surface of the skeletal plates. In some stars, short curved calcareous needles can be connected like two halves of scissors and form the so-called pedicellariae. The pedicellariae open and close using a system of special muscles. All muscles of echinoderms are smooth.

Digestive system begins in the center of the oral side of the disc with the mouth, which is surrounded by a soft annular lip. There are no special organs for capturing and crushing food. The mouth communicates via a short esophagus with a large folded, mark-shaped stomach, which occupies the inside of the disc. The stomach passes into a short and narrow hindgut (often with a special rectal gland), opening in the center of the aboral side of the disc. From the stomach in the coelom of the rays there are 5 pairs of long blind protrusions, seated with lateral processes. Stars are big predators. They feed on a variety of invertebrates, but mainly attack sedentary forms, such as bivalves, sea urchins, and sea urchins. P . Stars swallow small prey whole, and to take hold of large prey, they turn the stomach out through the mouth and cover the prey with it; The latter is thus digested outside the body of the predator. Gathering on oyster shallows, the stars destroy large quantities of these mollusks.

Nervous system primitive. It lies almost entirely in the outer epithelium. The main part of the central nervous system consists of the perioral epithelial thickening, or nerve ring, and the five radial nerves extending from it, located at the bottom of the ambulacral groove. The nerves reach the end of the rays. Deeper, beneath this surface nervous system, in each ray there is another double, weaker deep radial nerve.

Sense organs. The organs of touch are the ambulacral legs, as well as five short tentacles at the ends of the rays. At the base of the tentacles lies an eye; The eyes are simple, similar to the eye pits, and are capable of determining only the degree of brightness of light. Asteroidea, apparently, have a sense of smell: they crawl in an aquarium after a moving piece of meat and after artificial removal of eyes.

Ambulacral system. The movement occurs using the ambulacral system - a system of channels filled with aqueous fluid. It begins on the aboral side of the disc with the madrepore plate. The pores of the plate lead into a special rocky channel, the walls of which contain lime. The canal descends to the oral side of the body and here flows into the perioral ring canal, which lies under the stomach. Five radial ambulacral canals originate from the annular canal, giving rise to lateral branches. Each branch sends a pedunculated canaliculus to the oral side, which passes between the ambulacral plates into one of the pedicles, and gives off a small hollow ampulla into the body. Ambulacral legs are hollow, very extensible muscular outgrowths, equipped at the free end with a small suction cup. The legs sit in 2 or 4 rows at the bottom of the ambulacral grooves of the rays. The movement is carried out in the following way. The elongated legs stick to the substrate with suction cups. Then the muscles of the legs contract, the liquid from the legs is pushed into the corresponding ampoules, and the legs themselves are greatly shortened. As a result, the animal is somewhat pulled up on its attached legs in the direction of movement. Next, the legs are detached from the substrate, by contracting the ampoules, liquid is again driven into them, they are extended in the direction of movement, again attached to the bottom, etc.

The speed of movement of sea stars (as well as other echinoderms) is low: a sea star crawls no more than 5-8 cm per minute.

Respiratory system. The ambulacral system also plays some role in the respiration of stars, but the main respiratory organs are the cutaneous gills. These are short thin-walled protrusions of the body wall into which the continuation of the coelom extends. They are found mainly on the aboral side of the animal, as well as on the sides of the ambulacral groove. Through the walls of the gills, oxygen dissolved in sea ​​water, diffuses into the coelomic fluid. The latter is transparent, colorless and contains numerous amoeboid cells.

Circulatory system. Inside the septum, which lies in the perihemal canals, lacunae of the circulatory system are located. They are united by a perioral ring. In addition, there is an aboral blood ring, connected through the so-called axial organ to the perioral organ.

In contrast to the perihemal system, lined with peritoneal epithelium, the circulatory system is a system of lumens in the connective tissue (lacunae), devoid of its own epithelial lining. Fluid accumulates mainly due to the flow of nutrients from the intestinal wall into the lacunae located here. Thus, it corresponds not so much to the blood as to the lymph of higher vertebrates, i.e. it spreads throughout the body nutrients.

Selection. There are no special excretory organs. A significant part of the metabolic products formed in the body is excreted with the help of amoeboid cells scattered in the fluid that fills all body cavities. When injecting finely ground ink as a whole, the amebocytes are loaded with paint grains and leave the body through its integument. At the same time, they select the thinnest parts of the body wall, namely the skin gills; through them come out entire clusters of amoeboid cells, loaded with ink and normal excretory products. Some of the excreta is directly deposited in the skin and other tissues in the form of clusters of yellow grains, etc. The supply of amoeboid cells in the body must be constantly replenished. Special lymphatic organs serve this purpose: the Tiedemann glands and the axial organ.

Reproductive system It's simple. Starfish are dioecious. The gonads have the form of branched, grape-shaped sacs, lying in pairs at the base of the rays and opening outward with the help of short canals between the rays. Reproductive products are excreted in surrounding water, where fertilization occurs.

Starfish have a highly developed ability to regenerate. In place of the torn ray, a new one grows. The cut off beam of some stars can be restored at the damaged end new star. Some stars ( Linckia) the process of disintegration of an animal into separate rays and subsequent regeneration occurs spontaneously, so that the ability to regenerate leads to asexual reproduction.

Classification and distribution. The Starfish class, which includes 3 orders, has an almost worldwide distribution. Starfish inhabit all areas of the World Ocean with normal oceanic salinity, but they are especially richly represented in tropical waters: in coastal zones, on shallows and banks, on coral reefs etc. The stars eat the polyps, and the dead areas of the reefs are rapidly destroyed by the surf. This order is quite widely represented in the temperate and northern regions of the globe, where multi-rayed stars from the family Solasteridae. In the Far Eastern seas it is often found forming large accumulations on the shallows. Patiria- blue with orange spots a star shaped like a pentagon with slightly concave edges. Representatives of the third order are also common in these same areas - Forcipulata, possessing very flexible rays and characteristic pedicellariae, consisting of three movably articulated skeletal elements.

Literature: A. Dogel. Zoology of invertebrates. Edition 7, revised and expanded. Moscow " graduate School", 1981

If you find yourself in the Dominican Republic, don’t miss the chance to visit the Blue Lagoon and get acquainted with its beautiful and unusual inhabitants - starfish. You will find shocking facts about these creatures in this article!

Starfish are not just beautiful decorations and decoration of the seabed. At first glance, they seem primitive and somehow unreal. But appearances are deceiving. These animals have a complex nervous and digestive system.

Well, for example: did you know that the starfish is a real predator? And stars can move along the seabed over considerable distances. And this is not all that is known about starfish.

Facts about starfish

We have collected for you the most Interesting Facts about these amazing animals.

According to the texture of the body surface, starfish are:

• smooth
• spiky
• prickly
• rough
• velvety
• mosaic
• plain and patterned
• bright and faded

Starfish come in a wide variety of colors. Most often this

• different shades of red
• blue
• brown
• pink
• violet
• yellow
• black

The deeper the sea star's habitat, the paler it is. Those individuals that live in shallow waters are distinguished by the brightest colors.

Food and hunting

Starfish have a kind of sense of smell - they are able to detect chemical substances. This helps them hunt.

Yes, yes - most starfish are real predators!

Here are just some of the inhabitants of the seabed that the stars hunt:

• shellfish
• crustaceans
• plankton
• sponges
• corals
• gastropods
• other invertebrates, including echinoderms. For example, sea urchins are one of the starfish’s favorite delicacies.

The process of hunting, absorption and subsequent digestion of prey requires a separate story. We advise the faint-hearted and impressionable to scroll through these details.

The starfish is not picky about food and eats everything it can digest. She does not disdain carrion.

On the abdomen of the starfish there is a mouth through which it absorbs prey. If any mollusk becomes its victim, then the starfish crawls onto it and sticks with its rays to its valves. Thanks to the adhesive lubricant, the star manages to stick very firmly to the shells of the mollusk.

After this, a long struggle begins: the mollusk squeezes the valves of its shell, protecting itself from the predator, and the star strives to open them to gain access to the contents.
As a rule, the outcome of this confrontation is disastrous for the mollusk: the starfish is much stronger. And besides, for a hearty lunch, a gap of only 0.1 mm is enough for her!

Then something fantastic happens: the starfish turns out its stomach, which can stretch up to 10 centimeters! The stomach penetrates the shell of the mollusk, where the entire digestive process takes place, lasting several hours.

Thanks to its expandable stomach, the starfish can even digest prey that is significantly larger than its size. There is a known case where a starfish died after swallowing a sea urchin so large that it could not spit out the remains.

Reproduction

Starfish reproduce in different ways:

• Reproduction by regenerative means.

Due to the softening of the connective tissue, the starfish breaks up into several parts or casts off its rays. Then full-fledged stars grow from these parts.

• Sexual reproduction.

In a starfish, the gonads are located in pairs at the base of each ray. During mating, males and females connect their rays and release sperm and eggs into the water.

Those species of starfish that bear offspring lay 200 or more eggs.

Female starfish, whose larvae are free-swimming, are capable of laying up to 200 million eggs!

Among starfish there are also unisexual species. The bodies of such stars produce both male and female reproductive products. They carry their offspring in a brood pouch or special holes on their back.

And there are also species that during their lives change sex from male to female (for example, the asterine starfish).

There are three types of starfish larvae:

• in one type of star, the egg hatches into a larva that swims freely and feeds on tiny pieces of algae. After a few weeks, it attaches to the bottom and gradually turns into a small star with a diameter of 5 centimeters.
• in another type, the larva has large reserves of yolk, which allows it to do without additional nutrition and grow into an adult star
• in those stars that live in cold waters, the larvae remain on the mother’s body and concentrate around her mouth. Therefore, during this period, the female has to do without food and move very, very carefully, arching her body so as not to harm the larvae.

The size of the larvae usually does not exceed 3-5 mm

Starfish larvae can be carried over enormous distances by currents.

The starfish becomes sexually mature only at the age of 2-3 years.

The starfish is almost invulnerable. From natural enemies she is protected:

• sharp thorns (sometimes poisonous)
• ability to bury itself in sand in case of danger

• shrimps
• shellfish
• polychaete worms

They settle on the back of the starfish and cause damage to its covering. The star herself tries by all means to get rid of uninvited guests.

Benefits for the eco system

Starfish have a positive effect on the ecology of the oceans and the planet as a whole:

• absorb and utilize carbon dioxide, harmful to the planet, which is becoming more and more in the Earth’s atmosphere every year
• are orderlies of the seabed, eating carrion and the remains of dead marine organisms, as well as weaker and sicker individuals of marine animals

Some of the brightest and most beautiful representatives of this species live near the southern coast Dominican Republic. You can get to know them by visiting the Blue Lagoon. A visit to this natural pool, located right in the middle of the Caribbean Sea, is included in all excursions to the island of Saona.

The Blue Lagoon, as well as the islands of Saona, Catalina and Catlinita are part of the Eastern National Nature Reserve. And all the nature in these territories is carefully protected.

The lives of starfish are also protected. In order to preserve the population of this species, as of October 2017, it was prohibited to remove starfish from the water. And yet, starfish, as before, decorate the bottom of the water area and no one will stop you from admiring them.

Let's take care of nature and the fragile lives of starfish!
And then everyone will be pleased to return to the Blue Lagoon again and again to visit their old star acquaintances.

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-needle

Luidia 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 comb

Patiria 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 scope of the rays is the most large 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 pacific

Solaster pacificus Djakonov, 1938

These cold-water stars prefer great 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 Hayashi

Henricia 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 Pacific Ocean 28 species of Henricia were noted, of which 7 species were recorded for 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 antisticta

Lysastrosoma 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 causticus

Distolasterias 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.
Dystolasteria is 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

Distinctive feature This small seaside star has 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 spinosa

Evasterias 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 reticularis

Evasterias 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 star

Asterias 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. Males crawl around spawning females, slightly lifting the central part and sweeping out their reproductive products white. 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?