Morphological characteristics of chelates
The tortoise basically retained its original body shape. There is a nail bridge between the dorsal nail and the abdominal nail, and the nail is composed of a membranous osteogenic plate ossified by dermis and a shield covered by keratinization of epidermis. The number of shield and bone plate increases year by year, and there are growth lines on the shield, while the top area of the shield and its adjacent small pieces are often worn away. The carapace has an upper dome with 8 ridges in the middle, 5 ridges on the upper shield and 8 pairs of ribs on both sides. Usually, the upper shield has 4 pairs of ribs. There are 1 1 pair of edge plates and 12 pair of edge shields on the periphery, and there are no plates or only traces in Tortoise.
Bone plates and shields vary in number and size, and they are bonded together to strengthen the firmness of tortoise shells. The abdominal nail is flat, including 9 bone plates and 6 pairs of shields. The turtle shell has no horn shield, instead it is a leather turtle skirt. Leatherback turtles have no complete carapace, but many small polygonal bone pieces are arranged in rows and close to the epidermis, which are not connected with the deep bone plate to form a large carapace, so they used to be called the suborder Yuanjia, and other turtles belong to Hymenoptera.
The head, neck and limbs can be retracted into the bone box to avoid being preyed. The limbs are short and thick, covered with horny scales, with five fingers and toes, and short and clawed. The tail is very short. The top of the skull is smooth without carved decorative lines, the palatal margin is flat and wide without teeth, covered with a thick horny sheath, and the front end is narrow into a beak. The tip of the beak has external nostrils. The head and eyes are round and slightly prominent, with eyelids and transient membranes, and the tympanic membrane is round and smooth.
Extended data:
A claw-like animal.
Green/Ocean/Turtle
Turtles belong to the genus Tortoise. There are symmetrical scales on the back of the head and a pair of scales on the forehead. The upper jaw is flat, the lower jaw is slightly hooked, and the jaw edge is serrated. The snout is short and round, and the front end of the upper jaw is not hooked. The carapace is heart-shaped and inlaid with shields; 5 spinal protective covers; 4 pairs of rib shields, the first pair of rib shields is not connected with the neck shield, and each side shield has 1 1 block; There is a single laryngeal mask in front of the laryngeal mask; There are a series of lower shields between the carapace and the abdominal carapace. The limbs are paddle-shaped, the forelimbs are longer than the hind limbs, and each limb has 1 claw inside. The carapace is olive or brown with yellow and white radial lines; The carapace is olive or brown, mixed with light markings; The male tail is long, reaching half of the body length, and the claws of the forelimbs are strong and bent into a hook shape.
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