Chaohusaurus is an extinctgenus of basalichthyopterygian, possibly ichthyosaur, from the Early Triassic of Chaohu and Yuanan, China. It has also been called Anhuisaurus and Chensaurus. It was described by Young and Dong in 1972. It was closer in form to Cymbospondylus and Mixosaurus than more advanced genera like Ichthyosaurus: it did not have the dolphin-like form of later ichthyosaurs; it had a more lizard-like appearance. It did have flippers, rather than webbed feet, but the neck is atypically long and there is no dorsal fin. The tail fin is wide-based and short. It is one of the smallest ichthyosaurs, being from 70 to 180 cm long. Its weight is estimated at 10 kg.
Chaohusaurus birthed its young viviparously, like later ichthyosaurs. However, unlike later ichthyosaurs, the young exited the birth canal head-first. Motani et al.(2014) cited this as evidence for a terrestrial evolution of viviparity in ichthyosaurs. It is currently the oldest discovered reptile birth ever known.