Not to be confused with Hainosaurus. Hanosaurus is a genus of small nothosauroid marine reptiles. Its fossil remains have been found in eastern China, and date to the Ladinian stage of the early Triassic period. The genus consists of only one known species, H. hupehensis. Hanosaurus is among the smallest known fossil marine reptiles. It is estimated at 80 centimetres in length. Based on the limited fossil remains, it appears that Hanosaurus was less well-adapted for an aquatic existence than other nothosaurs, and may have spent much of its time in shallow, coastal waters or on the shore.