Let's find out more about him …
In addition to the fact that this unusual sea animal, 15-18 cm in size, looks like a breakaway section of the rock to which it was attached, not the strangest thing, but strange, even unusual, that it is absolutely motionless, sitting still. We have already considered a variety of shellfish systems, which are also quite original. Nevertheless, this animal feeds, sucks in and passes water through itself, as a result of which microorganisms, plankton, and organic debris suspended in water are filtered out.
This is how they work:
A rare mineral, vanadium, was found in the transparent blood of this mysterious creature. In addition, these animals (let's reveal a little secret - these are ascidians) have all male and female characteristics, and, reaching puberty, reproduce and throw clouds of sperm and eggs into the water, hoping that they will hastily combine. Nature, truly a crazy creator, had to be invented!
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The accumulation of vanadium in the blood, self-regulation of sex is truly a miracle, allowing these ascidians to exist in the coastal zone of the ocean at a depth of 80 meters. This ascidian species, called Pyura chilensis, is found off the coast of Chile and Peru. Locals eat these ascidians raw or stewed, and those Europeans who ventured to taste this exotic dish describe it like this: "bitter" and "soapy" piece of something incomprehensible, with a strange taste of iodine.
Well, what else can you expect from a piece of stone meat? Perhaps vanadium, a mineral also found in crude oil and tar sands, gives this taste. In the ascidians of the species P. chilensis, the content of vanadium in the blood may be 10 million times greater than in the surrounding water, and where it comes from remains to be determined.
Among the ascidians of the genus Pyura, sea tulips (Pyura spinifera) have no less amusing shape. They usually attach to the substrate on long legs (apparently, on a tail that has not completely fallen off), forming small bouquets, and the color is the same bright color as flowers on land. Most often, ascidians can be found in large and dense clusters numbering several thousand individuals or in small groups, but there are also single specimens. It is they who are direct evidence that these tunicates have both male and female gonads, because if an animal leads a sedentary lifestyle, then it is simply impossible to find a pair without leaving the place, and new colonies and single ascidians, nevertheless, continue to appear.
Well, now, in general, about ascidians
The most incredible and original animals live on the ocean floor. They can safely include a whole class of special bag-like animals - ascidians (Latin Ascidiacea) - these are primitive larva-chordates (Urochordata) or tunicates.
All over the world, the subtype Gang urochordate has about 1250 species of all kinds of ascidians. And they have the most exotic names: chamomile, sea syringe, pineapple - so named for the shape of the body, reminiscent of an ordinary pineapple, glass lamps, sea eggplant, and others. And in the coastal areas of Shandong province (China), there are ascidians, called sea breasts.
If you touch some ascidians with your fingers, then a powerful pressure of water from all the holes will follow in response, as if injections are made from a syringe, it is for this unusual ability that they got their name - the sea syringe. After a powerful release of water, the ascidians still continue to be in an excited state, while their bodies become soft, lose their shape and resemble rags dangling due to the current.
Some of these primitive animals can be encountered in the intertidal zone of oceans and seas, and some will have to be reached to the very depths. Adults are sedentary, firmly attached to the surface of the seabed, stones, shells, and they take root on the bottoms of ships or on the shells and backs of other marine life, such as crabs. Moreover, ascidians can settle both individually and in whole groups.
The main food for ascidians, in addition to animal and plant waste, which they extract from the water suspension, is plankton. The body of animals is covered with a shell (mantle), which has a leathery or cartilaginous consistency. With this mantle, the ascidians are in contact with various surfaces.
At the ends of the mantle there are a pair of fringed holes, and the ascidians themselves most often stretch out in the form of tubes of different configurations depending on the species. One hole serves to suck in water, from which the ascidians simultaneously extract food and respiration, the other outlet serves to remove waste materials. Inside the shell is the body of the ascidians, consisting of a thin-skinned gill sac, pierced with vessels and numerous crevices. The entire inner surface is covered with cilia.
Water enters through one hole, and fills the gill sac, then through the slits it enters the space (cloaca), which, as a communicating vessel, has an outlet to another opening - the intestinal canal, located below the gill sac. The curling gut also opens in the cloaca. The ascidians also have a heart located behind the intestine.
All ascidians are hermaphrodites, but eggs dropped directly into the water receive collective fertilization. The eggs are hatched through the cloaca, and the embryos undergo metamorphosis in the water. First, the hatched larvae set off for free swimming until they find a place to settle for the rest of their lives.
Newborn ascidians, like tadpoles, have eyes and a bladder that contains something like a nascent brain. But this brain in an adult does not develop, but disappears and in its place only a node of nerve endings (ganglion) remains. In addition, the larva has a well-developed tail, which allows them to change direction of movement. Nevertheless, after several hours, the front end of the body gradually undergoes changes, and, having fixed on some object, finally turns into an adult, and the tail gradually decreases and completely disappears.