Nudibranch mollusks are a large group of gastropod sea snails. The bulk of these creatures are relatives of ordinary land slugs. However, nudibranch mollusks differ from the latter in a number of unique morphological features. Based on this, they are classified as a special, separate order of mollusks, where there are thousands of different species.
Appearance
Nudibranch molluscs are morphologically similar to common 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 distinguishable eyes. These processes also serve as an olfactory organ for nudibranch mollusks.
As for the usual shell for snails, nudibranchs do not have such. Their body, outwardly similar to a sponge, is not covered by anything. protection from naturalEnemies in the habitat for most of them are poison, which is produced by special cells.
Internal structure
Nudibranch mollusks are divided into several groups according to the internal structure of the body: eolidids and doridids. Representatives of doridids have gills located in the back of the body. The large liver is responsible for digestion and filtering of substances entering the body. Doridids have a genital opening on their right side.
Eolidid molluscs do not have true gills. Their replacement is the so-called papillae - elongated outgrowths that are located in rows on the back of such creatures and extract oxygen from the water. The liver, which is responsible for filtering substances 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. During reproduction, such creatures touch their bodies for a few moments and fertilize the sex cells.
Food
Representatives of nudibranch molluscs feed on small sea creatures. Their prey is mainly sedentary organisms: sponges, sessile jellyfish, bryozoans, sea anemones. Among some species, cases of cannibalism have been recorded, in particular, eating clutches of eggs of their own kind.
Nudibranchs search for prey by smell. Having found a potential victim, the mollusks crawl on top of it, after which they begin to scrape off soft tissues with a radula - a hard grater located in the oral cavity.
Habitat
Nudibranch mollusks are marine animals. Their highest concentration is observed in tropical regions. They live at relatively shallow depths. However, among the nudibranchs there are also such mollusks that are able to lead an active life in polar waters.
Such creatures are hermits and do not form groups. They do not have permanent habitats. Throughout their lives, mollusks are in constant motion, trying to get food for food. True, nudibranch mollusks move extremely slowly. Therefore, they are unable to travel significant distances from their birthplace.
Sheep leaf
Let's find out all about the sheep leaf nudibranch. In fact, little is known about this creature so far. Outwardly, the mollusk resembles a luminous ball, which seems to consist of greenish fur. In the body of an animal there are special cells that produce oxygen through photosynthesis. The front part of the slug resembles the head of a tiny lamb, for which the creature got its unusual name. The sheep leaf mollusk lives off the coast of the Philippines, Indonesia and Japan.
Glavk
The nudibranch clam Glaucus outwardly resembles a man-made brooch, rather than a sea slug. On the sides of its elongated bluish body are several pairs of branched processes.
This close relative of snails spends most of its time at the surface of the water and does not likesink to the bottom. To maintain the buoyancy of its own body, the mollusk swallows an air bubble.
The Clam Glaucus is a poisonous creature. Toxic substances it is obtained with food. Its main prey are the Portuguese man-of-war jellyfish, which are known for their extremely poisonous tentacles. Moving in the water column, Glaucus attaches itself to the body of a jellyfish and, as necessary, separates pieces of flesh from it, which it uses as food and matter for laying fertilized eggs.
Nudibranch clam golden lace
Let's continue to consider the most unusual representatives of the nudibranch order. An extremely interesting creature is a mollusk called golden lace. In reality, the creature is similar to a piece of lace fabric, which shimmers with a bright glow. This peculiar shellless snail was recently discovered off the Hawaiian Islands.
Yanolus
The Janolus nudibranch is another rather unusual underwater creature. This marine inhabitant lives in deep-sea zones near the bottom. Outwardly, it resembles a horned snail, the translucent body of which is strewn with luminous spikes. From a distance, this tiny nudibranch looks like an exotic flower.
In closing
As you can see, there are quite a few varieties of such extraordinary creatures as nudibranch molluscs. All of them have an outlandish and bright look. Therefore, they are in demand among aquarium lovers. ActuallyNudibranchs are not only a real decoration of nature, but also take part in the formation of marine ecosystems.
