In the fauna of our planet, reptiles, numbering about 6 thousand species, are represented by several biological groups. One of them is the Turtle squad. Contains 328 species, grouped in 14 families. In this article, we will study the structure of the skeleton of a turtle, as well as the features associated with the water-land way of life of this animal.
Anatomical structure
Representatives of the detachment live in the steppes, foothills of Pakistan and India, in the deserts of Turkmenistan, Syria and Libya. As in other animals belonging to the reptile family, in the structure of their body, as well as in the processes of life, a number of idioadaptations to a dry and hot climate can be found. Among such devices, dense skin integuments, the absence of mucous glands, the presence of horny scales and scutes are distinguished. These formations consist of fibrillar proteins - keratins. Their function is to increase the mechanical strength of the outer cover.
Since land turtles, for example, steppe, Central Asian, feed on fairly rigid plant foods, they have a beak on their heads - a kind of process that has sharp edges with teeth. They turtles tear off parts of plants and rub them with tuberous ledges. The eyes are also located on the head. They are limited to three centuries: lower, upper and third. Presented in the form of a leathery film, covering the eye only half. All turtles have well-developed binocular vision and are well versed in the environment.
Tortoise skeleton departments
To answer the question of whether the turtle has a skeleton, we recall that the body of the reptile is anatomically divided into 4 parts. It consists of a head, neck, trunk and tail. Consider the structure of the turtle in the context. So, her spine consists of 5 departments: cervical, thoracic, lumbar, sacral and caudal. The skeleton of the head is completely bony. It is connected to the neck through two movable vertebrae. In total, the turtle has 8 cervical vertebrae. The head is drawn into the shell at the moment of danger, due to the presence of a hole in it. Land reptiles perceive low frequency sounds. Turtles are referred to as “silent” animals, since their vocal cords are anatomically underdeveloped. Therefore, they emit a hiss or squeak.
The structure and functions of carapace
Continuing to study the skeleton of a turtle, we will consider the upper part of its shell. It has a bulge that looks like a small bell. In land turtles, it is especially tall and massive, in aquatic turtles it is flatter, streamlined. Karapaks consists of two layers. The outer one contains keratin flakes - scutes, and the lower one has a bone structure. The arches of the vertebrae of the lumbar-thoracic region and the ribs are attached to it. The coloring and drawing of the carapace of the carapace of the carapace scientists are used by taxonomists to determine the species of animals. It was because of the carapace that turtles were and remain an object of fishing. A frame for glasses, cases, knife handles are made from it. The shell has several holes in which the animal draws its head, limbs and tail at the time of danger.
Plastron and its meaning
The lower part of the shell is called a plastron. Between him and the carapace is the soft body of the animal. Both of its halves are united by a bone shell. Plastron itself is an anatomical derivative of the forelimb belt and ribs. It is as if "soldered" into the body of a turtle. Ground forms have a massive plastron. And in marine life, it is reduced to cruciform plates located on the abdominal part of the body. Concentric lines form on the carapace shield due to growth. According to herpetologists can determine the age of the turtle and its state of health.
Characteristic of the skeleton of the belts of the front and hind limbs of the turtle
The skeleton of a turtle, the scheme of which is given below, indicates the belonging of animals of this species to reptiles. The bones of the forelimb belt are attached to their spine: scapula, collarbone and crow formation. They are located in the middle of the chest. The shoulder blade is connected to the carapace by the muscle fold at the location of the first vertebra. The hind limb belt consists of pubic, iliac and ischial bones. They form the pelvis. The tail section consists of many small vertebrae, so it is very mobile.
Features of the structure of the limbs of land turtles
The forelimbs of reptiles consist of the shoulder, forearm, wrist, metacarpus and phalanx of the fingers, which is similar to the skeleton of other classes of terrestrial vertebrates. However, there are differences in the structure of the bones of the forelimb. For example, the tubular bone of the shoulder is short, and their number forming the wrist is less than in mammals. The hind limbs also have anatomical features. The femur is very short, and their number in the foot is also reduced. This is especially noticeable in land turtles: box-shaped, rubella, steppe. Since they move on the surface of the earth, the bones of the phalanges of their fingers experience constant mechanical stress. Thus, the skeleton of the turtle has the necessary idioadaptations that contribute to its adaptation to the habitat.
Trachemys tortoise: structure and features of life
Among all other species, this animal is most popular as a home inhabitant. The structure of the red-eared turtle is typical of freshwater forms. Her head is well mobile, her neck is long, the carapace is represented by green carapace, and the plastron is yellow. Because of this, the tortoise is often called yellow-bellied. The limbs are massive, covered with horny shields, ending in claws. In nature, they feed on insects, living abundantly along river banks, larvae and fry of fish, as well as algae. The female is easy to distinguish from the male: it is more massive and longer, and its lower jaws are larger. These animals breed in the period from late February to May, laying from 4 to 10 eggs in sand pits. Small turtles hatch usually in July or August.
Land species of turtles
This group of reptiles is represented by such animals as the Central Asian tortoise, listed in the Red Book, Balkan, Panther. There are only about 40 species. The external skeleton of a turtle is a shell. It is very massive, with a high raised plastron. The animals themselves are quite inactive. The Central Asian tortoise is little dependent on water sources. She can do without it for a long time, eating juicy leaves or shoots of herbaceous plants. Since the animal has to adapt to the dry climate of the steppe or semi-desert, its annual activity is strictly regulated. It is only 2-3 months, and the rest of the year the turtle spends in a dormancy or hibernates in burrows dug in the sand. This happens twice a year - in summer and winter.
The structure of the tortoise land is characterized by a number of devices associated with life on land. These are columnar massive limbs, the phalanges of the fingers of which are completely fused, leaving short claws free. The body is covered with horny scales, preventing excessive evaporation and ensuring the preservation of water in the tissues of the animal. Thus, the animals are reliably protected by a heavy-duty bone-horn shell. In addition, they can scare away potential enemies with sharp hissing sounds or very fast emptying of the volume of the bladder. All types of land turtles are centenarians. They can live from 50 to 180 years. In addition, they have high adaptability and resilience.
Nevertheless, let's not forget that 228 species of turtles need protection and are on the verge of extinction. For example, the range of the green turtle is rapidly decreasing. It serves as an object of fishing, as a person eats its meat. Due to urbanization and a decrease in the area of natural habitat, the number of animals is reduced annually. The question of the appropriateness of keeping turtles in human dwellings remains controversial, even if they are localized in specially equipped terrarium conditions. A negligible amount of these animals survive in captivity until their biological age. Most die from the ignorant and irresponsible attitude of a person towards them.