The diversity of fauna of our planet is very large. Among its representatives are such interesting species of amphibians as legless amphibians. Otherwise they are called "worms."
Squad Legless amphibians: structural features
Outwardly, they resemble large worms. This similarity is due to the presence of numerous annular body intercepts. A small head connects to a long body that has no tail or limbs. Cesspool is located at the back pole of the body.
Dimensions usually do not exceed 45 cm. But there is one exception. We are talking about the Thompson worm, which lives in the Colombian mountains. Her body can reach a length of 1.2 meters.
Under the skin of the worms there are special scales, which were a sign of the distant carapace ancestors of legless amphibians.
These organisms have characteristic signs of fish: the presence of a large number (200-300) of vertebrae on the remains of the chord. The heart consists of one atrium, separated by an incomplete septum, and one ventricle. The structural features of the forebrain indicate a higher degree of development of worms compared to other amphibians.
Environmental adaptations
Legless amphibians live underground. The consequence of this is the lack of organs of vision - the eye. Their rudiments hide under the skin or grow into the bone. Hearing is also poorly developed. There is no auditory opening and eardrum, there is an inner ear, but it has no connection with the environment. Therefore, legless amphibians are able to capture only loud sounds with a frequency of 100-1500 hertz. Poor development of the above senses is compensated by excellent sense of smell.
The color is quite modest. Skin color ranges from gray and brown to black. Nondescriptness helps worms in disguise. There are exceptions. In nature, you can find specimens of bright yellow and blue.
Food and travel
They feed on blind snakes, earthworms, snake-tailed snakes, soil insects and mollusks. Some ringed worms use termites and ants as their main food.
Legless amphibians have adapted perfectly to their lifestyle. A small, sturdy head makes it easy to make your way underground. A long body and a large amount of mucus also helps in moving. Its selection is due to the numerous skin glands concentrated in the rings of the anterior section. This feature saves worms from attack by snakes, termites and ants.
Spread
Tropical areas with a humid climate are an ideal habitat for worms. They are common on the islands of the Pacific and Indian Oceans; in the river systems of Colombia, Amazon and Orinoco. In Africa, America, Asia, these amphibians are ubiquitous. Do not live in Australia and Madagascar.
Breeding
Detailed studies on this issue have not been conducted. But one thing is certain: reproduction is internal. The cesspool of males can turn outward, forming a copulative organ, thanks to which it is possible to carry out real mating. This trait characterizes all animals of the order Legless amphibians. Representatives who live in the aquatic environment have acquired several devices for this. In particular, their cesspool has suction discs. With their help, a pairing of mating individuals occurs. The mating time is 3 hours. Unlike most other amphibians that lay their eggs in moist ground, worms do not need a river or lake for this.
Instead of water, they use their own mucus. The order Legless amphibians is also characterized by live birth. The duration of pregnancy is 6 months or more, from 3 to 7 cubs are born. The body length of newborns is not more than 10 cm, but otherwise they are absolute copies of adult individuals of the order Legless amphibians. A photo of the cubs is presented below.
From the first days, they independently feed on gill sacs, which the female extracts for them.
Legless amphibians: representatives
The Central American worm lives in Guatemala. A female of this species is capable of bearing from 15 to 35 eggs. The birth occurs in May-June, when the rainy season starts. The length of the born cubs is from 11 to 16 mm. Despite their tiny size, they are very mobile and viable. Rapid growth allows them to reproduce at the age of two.
In female compression-tailed worms, 6 to 14 eggs are formed. When the larvae do not have enough yolk present in the eggs, they are selected from the egg shells, but are not yet born. Their habitat for some time is the mother's oviduct. Little worms already have leaf-shaped teeth at that time. With their help, they scrape the walls of their temporary shelter, which leads to the release of nutrient mucus. They eat it as food.
They also receive oxygen from their mother. With the help of large gelatinous gills present in the larvae, they “stick” to the walls of the oviduct, and oxygen is thus supplied to them.
For land worm fisheries living in India, Sri Lanka and the Great Sunda Islands, egg-laying is characteristic.
They are large, in one masonry there are from 10 to 25 pieces. Due to the dense shell covering them, and special outgrowths with which the eggs are attached to each other, the lump of eggs is a compact mass. The female curls up and hatches the eggs, abundantly lubricating them with mucus. Due to this, they increase in size by almost 4 times. Hatching, these legless amphibians, representatives of the adult generation of which are land, live for some time in the water until they finally mature.