Stegosaurus dinosaur artwork Stegosaurus was a herbivorous dinosaur and is the bestknown member of the group Stegosauridae It was about metres long and metres tall and weighed about tonnes A row of bony plates ran down its back These may have been used as cooling fins or in mating displays The spikes on the end of the tail were probably used to defend against predators The rear legs were longer than the front legs Stegosaurus lived during the late Jurassic period between and million years ago Its remains have been found in North America Europe Africa and Asia