[Lee Stewart]

Try to picture a reptilian version of a dolphin, and you won't be far off the appearance of an ichthyosaur. This diverse group of pointed-nose predators evolved to have dolphin- or fish-like bodies, but they looked far more menacing. Ichthyosaurs evolved around 250 million years ago and went extinct around 90 million years ago. While there were ichthyosaur species as small as 1 foot (0.3 m) long, the group was home to several giants in the late Triassic period. In 2018, researchers estimated that a fossilized jawbone from the U.K. belonged to an ichthyosaur that was more than 85 feet (26 m) long, which is nearly the size of a blue whale (Balaenoptera musculus).