/Serpentiformes

Serpentiformes

Excerpted from the Encyclopedia of China

Hanyu Pinyin she mu

Chinese entry Serpentiformes

Foreign language entry Serpentiformes

Author Zhao Ermi

Knowledge classification: Classification search/Serpentiformes

Squamous order 1 order . The body is slender, has no limbs, and definitely no forelimb girdle. About 2,500 species are known. There are about 200 species in China. Worldwide distribution mainly occurs in the tropics and subtropics. Found in arboreal, burrowing, freshwater and seawater. The minimum length is 100 mm, and the largest is more than 10 meters long, such as the anaconda in South America. Lower species often have hind limb belts, and a few still have remnants of hind limbs outside the body. There are no ear holes, no eardrum, tympanum, and Eustachian tube. Except for some cave-dwelling species whose eyes are hidden under the scales, the eyes are covered with a transparent film formed by the healing of the upper and lower eyelids. The tongue is slender, bifurcated, and can be retracted. The neck is generally inconspicuous. The trunk and tail are separated by a transverse cloacal anal hole. The characteristics of the body structure are mainly related to the thinning and elongation of the body shape. Most snakes are also related to the ability to swallow large food. The lengthening of the body is not due to the lengthening of the vertebrae, but to the increase in the number of vertebrae. As many as 141 to 435 pieces. Since there are no front or rear limbs, the spine is only differentiated into the dorsal vertebrae before the sacral part and the caudal vertebrae after the sacral part. The connection between the front and back vertebrae includes a pair of anterior facet joints and a pair of posterior facet joints, as well as the vertebral body joints. There is also a pair of joints between the vertebral processes and the vertebral arch concavities. There is a subvertebral process under the vertebral bodies of the front dorsal vertebrae, the rear dorsal vertebrae, or the entire dorsal vertebrae. There is often a pair of vein processes below the tail vertebra. Except for the first two dorsal vertebrae, each dorsal vertebra from the third dorsal vertebra is connected to a pair of long ribs. Internal organs also grow, and pairs of organs are often arranged front to back or degenerate on one side. The maxilla, bones and wing bones of snakes are loosely connected to the brain. There are some barb-like teeth on them, which are used to grasp food when swallowing. These paired bones can move alternately. Move food toward your mouth to make it easier to swallow. The left and right halves of the mandible are connected by ligaments and connected to the skull by square bones, so the mouth can be opened very wide, and the skin of the mandible is loose, so large objects can be swallowed. Without a sternum, the rhythmic contraction of the abdominal muscles can move the entire large food swallowed from the pharynx into the stomach. There is a pair of mating organs on both sides of the base of the male snake's tail. During mating, they turn out from the inside to the outside through the cloacal anal hole. Only one of them is used for each mating. Oviparous or ovoviviparous.

According to the current classification system, it can be divided into 3 suborders and 11 families.

Scolecophidia is divided into Scolecophidae, Scolecophidae and Scolecophidae. The suborder Henophidia is divided into the family Anacondae, Tusperidae, Acupunidae, Endosperidae and Scropodidae. The suborder Caonophidia is divided into the Colubridae (there are several subfamilies), Cobras Families (including Cobrainae, Platycerinae, and Hybridinae) and families (including Lepidopterinae, Pleuropodinae, and Viperinae). With the exception of most of the colubridae, all snakes in this suborder are venomous.