The diversity of the fauna of our planet is very large. Among its representatives there are also such interesting species of amphibians as legless amphibians. Otherwise they are called "worms".
Squad Legless amphibians: structural features
They look like big worms. This similarity is due to the presence of numerous annular interceptions of the body. A small head is connected to a long body, which has neither a tail nor limbs. The cloaca is located at the posterior pole of the body.
Sizes usually do not exceed 45 cm. But there is one exception. We are talking about Thompson's worm that lives in the Colombian mountains. Her body can reach a length of 1.2 meters.
Under the skin of the worms are special scales, which were a sign of the distant armored 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 notochord. The heart consists of one atrium, separated by an incomplete septum, and one ventricle. Structural features of the forebrain indicate a higher stage of development of caecilians compared to other amphibians.
Adaptation toenvironment
Legless amphibians live underground. The consequence of this is the absence of the organs of vision - the eyes. Their rudiments are hidden under the skin or grow into the bone. Hearing is also poorly developed. The ear canal and tympanic membrane are absent, the inner ear is present, but it has no connection with the environment. Therefore, legless amphibians are able to pick up only loud sounds with a frequency of 100-1500 hertz. The poor development of the above senses is compensated by an excellent sense of smell.
The color is rather modest. Skin color varies from gray and brown to black. Plainness helps worms in disguise. There are also exceptions. In nature, you can find specimens of bright yellow and blue.
Food and mobility
They feed on blind snakes, earthworms, shield-tailed snakes, soil insects and molluscs. Some annelids use termites and ants as their main food.
The legless amphibians have perfectly adapted to their way of life. The small, sturdy head makes it easy to cut a path underground. A long body and a large amount of mucus also help in movement. Its secretion occurs due to numerous skin glands concentrated in the rings of the anterior section. This feature saves the worm from attack by snakes, termites and ants.
Distribution
Tropical areas with a humid climate are an ideal habitat for caecilians. They are common on the islands of the Pacific and Indian Oceans;in the river systems of Colombia, the Amazon and the Orinoco. In Africa, America, Asia, these amphibians are ubiquitous. Do not live in Australia and Madagascar.
Reproduction
Detailed studies on this issue have not been conducted. But one thing is certain: reproduction is internal. The cloaca of males can turn outward, forming a copulatory organ, thanks to which true mating is possible. This feature characterizes all animals of the order Legless amphibians. Representatives that live in the aquatic environment have acquired several devices for this. In particular, their cloaca has suction discs. With their help, mating individuals are connected. The duration of mating is 3 hours. Unlike most other amphibians that lay their eggs in damp ground, worms do not require a river or lake to do so.
They use their own slime instead of water. 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, and otherwise they are absolute copies of adults of the order Legless amphibians. A photo of the cubs is shown below.
From the first days, they feed on their own gill sacs, which the female produces for them.
Squad Legless amphibians: representatives
The Central American worm lives inGuatemala. The female of this species is capable of carrying from 15 to 35 eggs. Childbirth 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.
A female squawk-tailed caecil develops from 6 to 14 eggs. When the larvae do not have enough yolk in the eggs, they get out of the egg shells, but are not yet born. Their habitat for some time is the mother's oviduct. Small 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 nutritious mucus. They eat it.
They also get oxygen from their mother. With the help of the large gelatinous gills present in the larvae, they "stick" to the walls of the oviduct, and thus oxygen is supplied to them.
Egg laying is characteristic of the land worm, a fish snake found in India, Sri Lanka and the Greater Sunda Islands.
They are large, in one clutch there are from 10 to 25 pieces. Due to the dense shell that covers them, and the special outgrowths with which the eggs are attached to each other, the caviar lump is a compact mass. The female curls up and incubates the eggs, smearing them abundantly with mucus. Due to this, they increase in size by almost 4 times. Having hatched, these legless amphibians, the representatives of the adult generation of whichare terrestrial, live in the water for some time before they finally mature.
