Nudibranchs: description, representatives

Nudibranchs are a large group of gastropod snails. The bulk of such creatures are relatives of ordinary land slugs. However, the nudibranch mollusks differ from the latter in a number of unique morphological features. Proceeding from this, they are considered to be a separate, separate order of mollusks, where there are thousands of different species.

Appearance

Nudibranchs are morphologically similar to ordinary garden snails. The basis of the body of these miniature inhabitants of the seas and oceans is a flat foot, which serves as a means of transportation for them. In the anterior part of the body there are stalked outgrowths. At the ends of the latter are tiny, barely discernible eyes. These processes also serve for the nudibranchs with the olfactory organ.

As for the shell that is habitual for snails, there are none for nudibranchs. Their body, which looks like a sponge, is not covered. Protection from natural enemies in the habitat for most of them acts poison, which is produced by special cells.

Internal structure

Nudibranchs in the internal structure of the body are divided into several groups: eolidides and dorylides. Representatives of doridids have gills located in the back of the body. For digestion and filtration of substances entering the body, a large liver responds. On the right side of the doridids there is a genital opening.

The mollusks of the eolidid group do not have real gills. Their replacement is the so-called papillae - elongated outgrowths, which are arranged in rows on the back of such creatures and extract oxygen from the water. The liver, which is responsible for the filtration of substances coming from the environment, is divided into separate lobes. Like the previous group of mollusks, eolidids have a genital opening, which is always on the right side. When multiplying such creatures for a few moments touch the bodies and fertilize the sex cells.

Food

Representatives of the nudibranch mollusks feed on small marine creatures. Their prey are mostly sedentary organisms: sponges, sessile jellyfish, bryozoans, anemones. Among some species recorded cases of cannibalism, in particular, eating egg clutches of their own kind.

Nudibranchs are looking for prey by smell. Having found a potential victim, the mollusks crawl on top of it, after which they begin to scrape off the soft tissues of the radulae - a solid grater located in the oral cavity.

Habitat

Nudibranchs are marine animals. The greatest concentration is observed in tropical regions. They dwell at a relatively shallow depth. However, among the nudibranchs there are also such mollusks that are able to conduct active vital activity in the polar waters.

Such beings are hermits and do not get lost in groups. They do not have permanent habitats. Throughout life mollusks are in constant motion, trying to get food for food. However, the nudibranchs move extremely slowly. Therefore, they can not move to significant distances from the place of birth.

Sheep leaf

Let's find out all about the nudibranch sheep leaf. In fact, little is known about this being today. Externally, the mollusc resembles a luminous tangle, which seems to consist of greenish fur. In the body of the animal there are special cells that produce oxygen through photosynthesis. The front part of the slug resembles the head of a tiny sheep, for which the creature got its unusual name. Inhabit the shellfish sheep leaf from the races of the Philippines, Indonesia and Japan.

Glaucus

Nudibranch of the Glaucus externally resembles a man-made brooch, rather than a sea slug. On the sides of its elongated body of a bluish hue there are several pairs of branched processes.

This close relative of snails spends most of the time at the surface of the water and does not like to sink to the bottom. To maintain the buoyancy of one's own body, the mollusc swallows an air bubble.

Glaucus is a poisonous creature. Toxic substances are obtained with food. Its main prey is the jellyfish Portuguese boat, which are known for their extremely poisonous tentacles. Moving in the water column, the Glaucus attaches to the body of the jellyfish and, as necessary, separates pieces of flesh from it, which it uses as food and matter for the laying of fertilized eggs.

Nudibranchs golden lace

We continue to consider the most unusual representatives of the nudibranch. An extremely interesting creature is a clam called a golden lace. In fact, the creature is similar to a piece of lace fabric that shimmers with a bright glow. This peculiar snail without shells was recently discovered in the Hawaiian Islands.

Yanolus

Nudibranchs Yanolus is another rather unusual underwater creature. This marine inhabitant lives in the deep-water zones near the bottom. Outwardly it resembles a horny snail, whose translucent body is strewn with luminous spines. At a distance, this tiny nudibranch resembles an exotic flower.

Finally

Apparently, there are many varieties of such extraordinary creatures as nudibranchs. All of them have a strange and bright appearance. Therefore, they are in demand among fans of aquariums. In fact, the nudibranchs are not only a true decoration of nature, but also take part in the formation of marine ecosystems.