The difference between stone turtle and Chinese grass turtle

Stone turtles are also known as yellow-throated water turtles, stone money and fragrant turtles. Grass turtle is also known as tortoise, golden tortoise and so on. So what's the difference between stone turtles and Chinese grass turtles?

The skull of the stone tortoise has a bony zygomatic arch; the square yoke is cut with the retroorbital bone and the yoke (zygomatic bone); the frontal bone is cut in the shape of "W" with a pair of frontal bones. The back armor of the grass turtle is flat and has three longitudinal edges. The abdominal nail is brown and yellow, and each shield has large black-brown patches. The kiss is short. There are dark yellow stripes and maculae on the side of the head and throat, extending back to the neck.

The stone turtle, also known as the yellow-throated turtle, is about 15~20cm long, with a small head, smooth top, olive green, sunken upper beak, clear tympanic membrane, two yellow lines on the side of the head passing through the eyes, and a yellowish throat. The toenail is flat, brown-yellow-green or brown-black, with three ridges, the central one is more obvious, and the posterior edge is slightly serrated. The abdominal nail is yellow, and there are large ink spots on the outside of each shield. The limbs are flat, brownish gray on the outside, yellow on the inside, five fingers on the forelimb, four toes on the hindlimb, webbed between the fingers and a short tail.

The turtle body of Chinese grass is long oval, the dorsal armour is slightly raised, there are three longitudinal edges, and the ridge edge is obvious. The top of the head is black and olive, with smooth skin at the front and fine scales at the back. The ventral nail is flat and notched at the back end. The neck, limbs and exposed skin are grayish black or black olive. The male is small, has a long tail and smells bad. Female toenail from light brown to dark brown, abdominal nail brownish black, short tail, no peculiar smell. There are yellow linear markings on the side of the head and neck, there are three longitudinal ridges, and the trailing edge is not serrated; the back of the male is black or black, the female is brown, the ventral side is slightly yellow, and all have dark brown markings; the limbs are relatively flat, with claws and full webbed between the toes.