Temporal range: Upper Cretaceous
It had tiny horns behind its eyes and its arms were a bit longer than those of T. rex. It may have been an ancestor of T. rex. This bipedal meat-eater lived in marshes by streams in what is now Alberta, Canada, during the late Cretaceous period, 76-72 million years ago. It may have preyed upon Triceratops. It was named by D.A. Russell in 1970. The type species is D. torosus.