As a result of evolution, the class of reptiles began to appear as a great variety in different geographical areas: in the tropics, deserts, caves, in fresh waters and seas. This is an ancient highly organized group of land animals, which has about eight thousand species. They move on the surface of the earth in a creeping way, hence the name of the class. Reptiles include 4 orders: scaly, turtles, crocodiles and beakheads. Their development and flourishing is associated with a change in climatic conditions and the spread of the continental climate in the Mesozoic era.
The topic of the article is devoted to the most numerous order of the reptile class - the squamous order. It should be immediately noted that the classification of this group is very complex and confusing, something new is constantly introduced or the old is shuffled. Therefore, different sources may contain different information.
General characteristics of the squamous order
Scaly (from the Latin squama - "scales") have 6500 species and are considered today one of the most prosperous groups of reptiles. According to the latest scientific systematizationthe squamous order is subdivided into 5 suborders: snakes, lizards, iguanas, geckos and amphisbaenas. Representatives of the detachment are settled all over the planet and do not live only in harsh polar conditions.
In appearance and lifestyle, animals differ from each other, but they also have common features. The flexible body of the scaly is covered with horny scales or scutes, which, depending on the type of animal, may differ in color, shape and size. The quadrate bone of the upper jaw has a movable connection with the cranium. Another distinguishing feature is the long tongue, which performs the function of touch and smell.
Scaly reproduction
Scaly, like all reptiles, are heterosexual animals. Females have paired ovaries and oviducts that open into the cloaca, males have testes and vas deferens. Fertilization occurs inside, in the genital ducts of the female. A fertilized egg, moving along the oviduct, acquires protective coatings - embryonic and shell. Eggs are laid in the warmth of the ground or incubated inside the female until hatching immediately after laying.
Among the scaly species, there are also viviparous species. For example, an ordinary viper or a viviparous lizard: the fetus inside the mother is connected with her body by a complex system of blood vessels that provide it with the necessary nutrition and oxygen.
Snakes
In honor of these animals, temples were once built and whole cults were created, they were worshiped and idolized, legends and myths were composed. They scare someone with theirappearance, someone is of interest, the attitude of mankind towards them has always been ambiguous. We are talking about snakes, reptiles of the scaly order. This suborder consists of 18 families and includes 2700 species.
The structural features of the snake are a long body without limbs and a small head. Her spine is represented by only two sections - the trunk and tail, the vertebrae of which have a uniform structure. Representatives of this suborder have a cold, unblinking gaze, their eyes are covered with a transparent protective film and are devoid of eyelids - they see poorly. Also, snakes cannot boast of hearing, they do not have ear holes, they pick up sound vibrations from the ground. But all the disadvantages are compensated by the sense of smell, with the help of which snakes successfully navigate in space and hunt.
Snakes have a peculiar structure of the skull: the bones of the mouth apparatus, and some bones of the skull are movably connected to each other. The lower jaw has highly extensible ligaments, which explains the ability to swallow prey whole. The teeth of these scaly ones are very well developed, but they cannot chew with them: they are sharp, thin and bent back. Many snakes have venomous teeth, they have grooves through which poison enters the victim when bitten.
Lizards
The lizard suborder is a large and very common group of the scaly class of reptiles (or reptiles). It consists of 13 families, each of which has its own characteristic features: girdletails, gilatooths, teiids, monitor lizards, herrosaurs and others. Greatestthe number of species is concentrated in the tropics.
Most lizards are equipped with limbs, but there are also legless species. Unlike snakes, they have a sternum, and the bones of the jaw are firmly connected to each other. Most lizards have well-developed eyelids and eardrums. These scaly are known for their involuntary dropping of the tail, which then grows back.
The color of lizards can be the most diverse and performs a protective function, it harmonizes well with the surrounding reality.
Gecko suborder
Not everywhere geckos are classified as a separate suborder of scaly ones, however, some experts still distinguish it separately. The suborder consists of 8 families: scale-footed, carphodactylids, phyllodactylids, geckos, worm-like lizards and others. They live in tropical and subtropical regions and are mostly nocturnal.
The size of geckos is no more than 10-15 cm, but you can also meet a large individual. These representatives of the squamous order boast their unique fingers, which have special adaptations that help them to stay on any vertical surface. We are talking about expanded plates with intersecting rows of brushes of microscopic hairs.
Geckos are very peculiar in their behavior, which is not typical for other species: on the hunt, just before the throw, they rise on their hind limbs, and, with their heads held high, begin to swing their tails.
Suborder Iguanas
No other group of squamates can boast such a variety of life forms as iguanas. Like geckos, this suborder is not recognized by everyone. It has 10 families: collared iguanas, anoles, helmet lizards, chameleons, spiny-tailed iguanas and others. All iguanas are divided into two types of individuals, which differ in the characteristic shape and body structure. In arboreal iguanas, the body is laterally compressed, while in terrestrial iguanas, the body has a disc-shaped flattened shape.
The calling card of all iguanas is pleurodont teeth, which are attached to the inside of the jaws. The head of individuals is covered with multiple irregularly shaped scutes, and the back is covered with scales, transformed in places into horny spikes, tubercles and teeth.
Iguanas are mostly carnivores that feed on spiders, insects and worms. Larger individuals have vertebrate prey, most often lizards.
Amphisbaena
Reptile dvukhodki (amphisbaena) are very similar to lizards, so this suborder has long been recognized as their family. Unlike their relatives, amphisbaena lead an underground life and resemble worms in appearance. They include 4 families: Hirota, Palearctic worm-like lizards, Amphisbaenidae and Rhineurids.
Animals, which are classified as scaly, have a typical common feature - horny scales on the body. Amphisbaenas, on the other hand, have a worm-like body, covered with a solid horny film and entwined with transverse rings withintersecting grooves. Therefore, their appearance also resembles scales. The horny brushes that cover the head of most squamates have a burrowing function in Amphisbaena.
Amphisbaena prefer to live in termite nests. Like moles, they dig passages in the ground and easily move along them. Interestingly, on the surface of the earth they move in straight vertical lines.
Lifespan
The squamous squad does not differ in special longevity. Experts agree that there is a direct relationship between life expectancy and animal size. Large individuals of lizards live 20-30 years, and small ones no more than two years or even less. Geckos spend their lives up to 13-15 years, the numbers can be more, depending on the size of the individual. Snakes in nature reach an average of 30-40 years, but in captivity, thanks to human care, years are significantly added. There are species, for example, pythons, their age can reach up to 100 years.
It should be noted that the life expectancy of reptiles is significantly reduced as a result of disease, injury and predator attacks. But lately there has been a trend to keep exotic animals as pets and it certainly adds years to their life.
Meaning of the squamous order
Like all life on this earth, scaly reptiles have their purpose in nature and human life. They are active participants in the food chain, where the elimination or change in the number of one species will threaten a catastrophe for all others.
Lizards and snakes are of great benefit to people, destroying harmful insects and rodents that not only harm crops, but also carry dangerous infections. In addition, snakes are eaten by some peoples of the East. They believe that the meat and blood of the scaly give the body longevity, youth and he alth.
In medicine, the use of snake venom is also priceless, it is present in many medicines and ointments. And, on top of that, the skins of these reptiles are used in the manufacture of accessories and shoes.
Poisonous representatives
A separate subject of discussion will be the toxicity of some representatives of the squamous order. About a million people suffer from snakebites alone every year. And, despite the effectiveness of the treatment of modern medicine, mortality remains very high. A large number of attacks are recorded in tropical and subtropical zones.
What animals of the scaly order are dangerous and pose a threat to human life? As a rule, these are separate species of snakes and the gila-tooth lizard family. Some still mistakenly define iguanas as poisonous reptiles, but in fact, they do not have any toxic poisons. They transmit a large number of bacteria with their bite, which can cause inflammation. And no poisonous representatives were found in the suborders of amphisbaena and geckos.
In snakes, 5 out of 18 families are completely poisonous or contain poisonous species: already-shaped, aspid, viper, pit-headed, rattlesnakes. On the territory of Russia, a family of vipers is common. Attacks have been reported inSiberia, the Far East, the Middle Urals and the republics of Transcaucasia.
Interesting squamous facts
- Legless lizards can easily be confused with snakes. But upon closer examination, you can see the head and ear canals that are not inherent in snakes.
- Gecko is mentioned in the Bible as anaka (Leviticus 11:30).
- Snakes can hibernate for three years without eating.
- In Mexico, iguana dishes are part of the national cuisine.
- Poisonous snakes love classical music and enjoy dancing to it.
- The copperhead snake smells like fresh cucumbers.
- In the Mayan tribe, iguanas were revered, a house with them symbolized the house of a deity.
- The color of a chameleon depends on its emotional state, and not on the surrounding background.
- The king cobra eats snakes, including poisonous ones. Also, unlike other species, she takes care of her offspring.
