You will be shocked to learn that Ichthyosaurus was a type of ichthyosaur. It lived during the Early Jurassic, and has been found in the marine shales of Dorset and Somerset, England. Obviously the type genus of the whole ichthyosaur clade, it was named over two centuries ago, as one of the first good Mesozoic fossils described scientifically. Ichthyosaurus had a dolphin-like body, four crescent-shaped paddles, and large eyes ringed by bony sclerotic plates. It would have been a fast and agile swimmer, chasing down marine invertebrates and potentially small/young fish or marine reptiles.