English: Thyreosaurus is a stegosaurian dinosaur from the Middle Jurassic of what is now Morocco. It is characterized by a unique armor that resembled those of nodosaurid ankylosaurs more than those of its fellow stegosaurs. The bony growths appear to have laid flat on the animal's back, rather than standing erect. However, due to the disarticulated nature of the fossil specimen, their exact position remains unknown. Thyreosaurus is estimated at around 6 m in length, though this is based on an adult individual that had not yet reached its full size, so it could likely grow larger.