Monoclonius (meaning "single stem"; referring to the teeth, which have a single root)Creisler BS. (1992) "Why Monoclonius Cope was not named for its horn: The etymologies of Cope's dinosaurs" Journal of Vertebrate Paleontology, 12(3):313-317 Cope 1876 was a ceratopsian dinosaur from the Judith River Formation of Late Cretaceous Montana and Canada. It is often confused with Centrosaurus, a similar species of ceratopsian (some think the two may even be the same, of a different age or sex).