NEMETINS: What are, characteristics and examples

The Nemetz, also known as tape wormsThey are a elongated and flattened worms phylumof free and aquatic life, whose majority are sailor and only some sweets or inhabitants of wet soils. Some people often confuse them with flat worms, Platelmints, but their internal anatomy differs considerably. Its main characteristic is that they have a Tube or proboscis Used to capture the food and as a method of defense or to help in movement, hence its other common name, proboscid worms. There are approximately 1,200 species distributed in two classesAnople and EnoPla.

• They present various sizesfrom very small to huge as Lineus Longissimus It can reach 30 meters.
• Some have bright colors and others have pale or cryptic colorations.
• They possess bilateral symmetry and the contractile bodywhose anterior part is cylindrical and its rear flattened.
• Are Carnivores and voracious. They feed on living or dead dams, mainly anélidos and crustaceans. There may be some parasitic forms.
• Some species cavan holes Covered of mucus forming well -defined tubes.
• They have cilia They use to slide over the substrate on a mucus film, although there are excavating species that can move through peristaltic movements.
• Your digestive system is complete.
• Its circulatory system is closed and consists of contractile vessels located one on each side of the body that travel the entire length of the animal. Sometimes they have a dorsal vessel.
• They have a Proboscídeo apparatus independent of the digestive tract that can be equipped with a stiletto (enlapas class) or not (anopla). The stiletto is used to capture dams, since it is capable of introducing toxic substances in the dams immobilizing them.
• The gaseous exchange is produced by diffusion through the surface of the body wall.
• They possess Separate sexes with simple gonads. Some are hermaphrodites.
• They can reproduce asexually due to fragmentation and the regeneration process can occur in a mucous cyst.
• The fertilization is external and the eggs are released directly in the water or wrapped in gelatinous masses or inside tubes.
• The development of the embryo causes a Swimmer larvasimilar to a worm. On other occasions a swimming larva with peculiar characteristics called “Pilidium” is formed.

The Most of the Nemertinos are marine And they have benthic habits, although some live in sweetacuícoles or wet soils. Its geographical distribution covers From polar regions to the tropicswhich allows them to adapt to a wide variety of environmental conditions.

They usually live under rocks, algae, buried under sand and mud and in association with other invertebrates. Some species of the genus cerebratulus live in empty shells of mollusks. In summary, tape worms are aquatic animals that have a wide presence in marine and fresh water ecosystems worldwide.

One of the characteristics of the Nemertine edge is the presence of a proboscis or trunkindependent of the digestive system, used to capture dams. This opens in a pore at the anterior end of the animal and leads to a short channel called corner whose light continues with the proboscis. The proboscis consists of a long tube, rolled up in the Rincele, a cavity full of liquid that can be considered as a “celoma” due to its embryonic origin and structure. The posterior region of the proboscis binds to the corner by means of a retractor muscle.

But how do nemertinos feed with this structure? Nemertinos are very voracious predators who take their prey by launching their proboscis that sometimes possesses glandular papillae that produce mucus, mucus, adhering to the dam and rolling around. In those species that have a sharp tip stiletto, it penetrates and retains the dam. By retracting the proboscis the worm carries the dam to its oral cavity.

You may also be interested in this article about animals with trunk.

• Lineus Longissimus: Known as a giant tape worker, it is considered the longest nemertino reaching lengths of up to 30 meters. It is located in shallow northern sea waters.
• Marginatus cerebratulus: Native of the northern hemisphere where it presents a great distribution, this long and flattened worm is a good swimmer and can dig in the substrate. It has the habit of fragmenting when manipulated.
• Zygeupolia Rufa: It is a Bentonic Nemertino, excavator, who lives on the Canal de la Mancha.
• Carcinonemertes Errans: It is a tape worm that lives in symbiosis with the Dungeless crab (Metacarcinus Magister). It is not a parasite that feeds directly from the crab, but predates its developing eggs.
• Arhynchonemertes axi: It is the only worm within this group that lacks one of the most representative structures of tape worms: the proboscis.

Now that you know what the Nemertinos, their characteristics and examples are, do not miss these other ecology articles about the types of worms and the miriapods: what are, characteristics and examples.

If you want to read more articles similar to NEMETINS: What are, characteristics and exampleswe recommend that you enter our biology category.