Morphological characteristics of 1. (Black-necked turtle)? The carapace of adult turtles is black (the carapace of young turtles is slightly brown-black), rectangular, with obvious ridges in the center. The upper abdomen is black, and there are black patches on the edge of each shield. The head is large and wide, the kiss is blunt, the head is black, and there are yellow-green stripes on the side (the side or neck of the larva's head is orange). The limbs are black without stripes, and the fingers and toes are webbed. The tail is black and short. The female turtle has a larger body, a shorter tail and a cloaca hole closer to the posterior edge of the carapace. Male turtles are small in size, with thick and long tail roots and cloaca holes far away from the posterior edge of the carapace. ?

2. Morphological characteristics: the head is very large, and the width is almost1/2 of the width of the abdominal shell; The front end of the kiss is perpendicular to the beak edge, and the beak is thick; The carapace is arched and has three strong ridges; The shield is almost smooth; The neck shield is small, narrow and long, and the trailing edge is slightly concave; The first rose shield is wide at the front and narrow at the back, and the other shields are almost as wide as the first three pairs of rib shields. The edge of the carapace is neat, and the edge of the third to eighth roses is slightly upturned; The front edge of the abdominal nail is flat or slightly concave, and the rear edge has a notch, which is angled or curved; The nail bridge is obvious, and the axillary shield is smaller than the crotch shield A complete web between the fingers and toes. The tail tapers off. The back is black or dark brown, and the spine is black; The groove edge of the ventral black-brown shield is yellowish or greenish, the head, neck and limbs are olive yellow, and there are insect infection stripes on the head side, and yellow-green longitudinal stripes from the back of the eye to the top of the neck side. ?

3. (Trionyx sinensis) has a rectangular body, slightly raised carapace and three longitudinal edges with obvious edges. The top of the head is black olive, the skin in front is smooth and the scales in the back are fine. The abdominal nail is flat with a notch at the back end. The neck, limbs and bare skin are grayish black or black olive. The male is very small, with a long tail and a bad smell. When he is sexually mature, his carapace and abdominal carapace are black, and the olive green stripes on his skin fade and turn black. The female carapace is light brown to dark brown, and the abdominal carapace is dark brown, with short tail and no peculiar smell. Trionyx sinensis has strong adaptability to the environment, low requirements for water quality and great tolerance for poor water quality. High-density culture does not kill each other, and the prevalence rate is low.

4. (Trionyx sinensis) The carapace is relatively flat, 13, with three longitudinal edges. The carapace is brown, and there are large dark brown patches on each shield. Kiss short. There are several yellow spots with black edges on the head and throat, which extend backward to the neck. There are great differences between men and women in adulthood. There are webbed toes and claws. The female tail is short, the male tail is thick, and the female adult is almost twice as large as the male.

5. (Scarab) The back of the scarab is brown or gray-black, with three obvious black vertical stripes, and the middle one is the most obvious and the longest, so it is also called Sichuan-word turtle. The top of the scarab has a yellow diamond mark, which is smooth and scaleless. The beetle plate (abdominal nail) is transverse and connected by ligaments, so it is also called broken plate turtle. The hard skin around the edge of scarab is orange, so it is also called red-edged turtle.