1. An extinct marine reptile of the Mesozoic era, resembling a dolphin with a long snout, four flippers, and a vertical tail fin.
Usage: paleontology; often capitalized when referring to the genus Ichthyosaurus

Examples

• The ichthyosaurus was one of the most successful marine predators of the Mesozoic era.
• Fossils of ichthyosaurs have been found on every continent.
• Unlike dinosaurs, ichthyosaurs were fully adapted to life in the ocean.
• The ichthyosaurus had large eyes that helped it see in deep water.
• Scientists believe ichthyosaurs gave birth to live young rather than laying eggs.