Anatomy: Ichthyosaurus was about 6.5 feet (2 m) long and ay have weighed about 200 pounds (90 kg). It had a tall dorsal fin, a half-moon-shaped tail, paddle-like flippers, and smooth skin. The nostrils were near the eyes on the top of the head. It had massive ear bones and large eyes, probably indicating that it had acute hearing and keen eyesight. These marine reptiles gave birth to live young.

Diet: Ichthyosaurus' diet was mostly fish, but may have also included cephalopods (like straight-shelled belemnites).

Fossils: Hundreds of Ichthyosaurus fossils have been found in England, Germany, Greenland, and Alberta, Canada. Even fossilized dung (called coprolites) and fossilized skin impressions have been found. Ichthyosaurus, which means "fish lizard," was named by Charles Koenig in 1818.