Ichthyosaur
By the Upper Triassic they were similar in shape to dolphins and to fast predatory fish like tuna (convergent evolution). They are found in marine strata from the earliest Triassic to the Cretaceous. After transitional Triassic types like Mixosaurus and Cymbospondylus, they have essentially the same body shape. Californosaurus was one of the first to have the typical dolphin-like body shape.