Pliosaurus was a large marine reptile that lived during the late Jurassic period, around 150 million years ago. It belonged to the group of reptiles known as plesiosaurs, characterized by their long necks and large bodies. Pliosaurus had a robust, streamlined shape, with powerful limbs adapted for swimming and a large head filled with sharp teeth, making it a formidable predator in ancient oceans. Fossils of Pliosaurus have been found in various locations, including Europe and South America. This creature could grow up to 12 meters (about 39 feet) in length, making it one of the largest marine reptiles of its time. Its diet likely consisted of fish and other marine animals, showcasing its role as an apex predator in its ecosystem.