Hesperosaurus

Hesperosaurus was a large stegosaur, reaching about 6.5 metres (21 feet) in length and weighing around 3.5 metric tons (3.9 short tons). Some large individuals may have reached 5 metric tons (5.5 short tons).1

Hesperosaurus was a herbivore, meaning it ate plants. It was a quadrupedal plant-eater, like other stegosaurs.13

Hesperosaurus lived during the Late Jurassic period, about 156 million years ago. It lived a little earlier than other stegosaurs from the Morrison Formation.13

Fossils of Hesperosaurus have been found in the states of Wyoming and Montana in the United States of America. They were first discovered in 1985.1

Hesperosaurus had two rows of bony plates on its back and four spikes on its tail. The tail spikes, called a thagomizer, had two pairs: the front pair thicker and the rear pair thinner and more horizontal.1

Yes, Hesperosaurus is a dinosaur. It is a stegosaurian dinosaur, a type of armoured dinosaur.13