Ichthyosaur, a kind of reptile, was a "distant relative" of dinosaurs. They got back to sea and thrived during the Triassic period and Jurassic period. Ichthyosaur had no configuration of reptile. Its body was spindle-shaped with no collum, with head directly connected with body, which could decrease the resistance of movement under water. With long head, long and pointed snout full of sharp teeth, it was good at preying on fishes. Adapted with marine life, they were widely distributed. Many ichthyosaur fossils were found in China.

  Mixosaurus mataiensis

The first set of ichthyosaur fossil found in China is Mixosaurus mataiensis, a kind of primitive ichthyosaur with wide and short skull and nail-shaped teeth. It was found in Maotai of Guizhou Province.

  Chaohusaurus geishanensis

In 1965, a small ichthyosaur with a length no more than 1 meter was found in Guishan Mountain of Chao County in Anhui province. It had a triangular head and very long snout full of sharp teeth. Mainly it fed on mollusk living in seabed. This ichthyosaur is named Chaohusaurus geishanensis.

  Himalayesaurus tibetensis    

The most famous ichthyosaur fossil in China is the "Himalaya Ichthyosaur" (Himalayesaurus tibetensis) of 160 million years ago, found at south slope of Himalaya Mountains at altitude of 4,800 meters. From the fossil we can see, this ichthyosaur had a body length of over 10 meters. Its eyes on both sides of head were big, from which scientists presume that it had good vision. Skin bared, its body was spindle-shaped, exactly like today's porpoise. The long snout was armed with 600 razor-sharp teeth, and the four limbs had turned into fins: a fleshy back-fin on the back, and an unsymmetrical oblique tail fin on the tail just like that of shark. It fed on fishes and mussels in the shallow sea, and in its stomach there were often stomach stones to ground food. The discovery of Himalaya Ichthyosaur in Tibet speaks for itself that, today's Qinghai-Tibetan Plateau, the roof of the world, was an immensurable ocean 164 million years ago.