Shonisaurus

Shonisaurus is an ichthyosaur from the late Triassic period and is notable for its incredible size – it is one of the largest marine reptiles in history, growing up to 15m in length and nearly 30 tonnes in weight. This genus has a slim body and a long snout, and is a relatively slow swimmer despite having large flippers. While a juvenile Shonisaurus displays small teeth, these grow out by the time the genus reaches adulthood.