 Susannah Maidment and colleagues in 2008 proposed extensive alterations to the taxonomy of Stegosaurus . They advocated synonymizing S. stenops and S. ungulatus with S. armatus , and sinking Hesperosaurus and Wuerhosaurus into Stegosaurus , with their type species becoming Stegosaurus mjosi and Stegosaurus homheni , respectively . They regarded S. longispinus as dubious . Thus , their conception of Stegosaurus would include three valid species ( S. armatus , S. homheni , and S. mjosi ) and would range from the Late Jurassic of North America and Europe to the Early Cretaceous of Asia . However , this classification scheme has not generally been followed by other researchers . Galton , for example , has stated that Wuerhosaurus differs enough from Stegosaurus to be retained as a distinct genus . In 2015 , Maidment et al. revised their suggestion due to the recognition by Galton of S. armatus as a nomen dubium and its replacement by S. stenops as type species . 
