Ichthyosaurus was a marine reptile that lived during the Mesozoic Era, specifically in the early to late Jurassic Period. It resembled modern dolphins, with a streamlined body, long snout, and large eyes, which made it well-adapted for life in the ocean. Ichthyosaurs were not dinosaurs but were part of a group called ichthyosaurs. These creatures could grow up to 10 meters (about 33 feet) in length and primarily fed on fish and squid. Fossils of Ichthyosaurus have been found in various locations, including England, where they were first discovered in the early 19th century. Their unique features provide valuable insights into the evolution of marine reptiles.