Monolophosaurus was a medium-sized theropod dinosaur that lived during the Middle Jurassic period, around 165 million years ago. It measured about 5 to 7 meters (16 to 23 feet) in length and is best known for the distinctive single crest running along the top of its skull, which may have been used for species recognition or display. Monolophosaurus was a carnivore, equipped with sharp teeth and strong jaws for hunting smaller dinosaurs and other prey. Its fossils were discovered in China, offering valuable insights into the diversity of theropod dinosaurs in Asia during the Jurassic period.