Monoclonius

Monoclonius (meaning "single stem"; referring to the teeth, which have a single root) was a ceratopsian dinosaur from the Judith River Formation of Late Cretaceous Montana and Canada. It is often confused with Centrosaurus, a similar genus of ceratopsian (some think the two may even be identical, of a different age or gender). Monoclonius was described by Edward Drinker Cope in 1876.

Etymology

Contrary to what was stated in most popular or technical science publications prior to 1992, the name Monoclonius does not mean "single horn" or refer to its distinctive single nasal horn. In fact, the genus was named before it was known to have been a horned dinosaur, and had previously been considered a "hadrosaur". The name in fact means "single sprout", from Greek μόνος, monos, "single", and κλωνίον, klonion, "sprout", in reference to the way its teeth grew compared to its relative Diclonius ("double sprout"), which was named by Edward Drinker Cope in the same paper as Monoclonius. In Diclonius, Cope interpreted the fossils to show two series of teeth in use at one time (one mature set and one sprouting replacement set), while in Monoclonius, there appeared to be only one set of teeth in use as a chewing surface at any one time, with replacement teeth growing in only after mature teeth had fallen out. This salient feature of the tooth, which specimen is now lost, almost certainly precludes it from being centrosaurine: it probably indeed is hadrosaurian and was by mistake associated with the rest of the type material.

Diet and ecology

Monoclonius, like all Ceratopsians, was a herbivore. During the Cretaceous, flowering plants were "geographically limited on the landscape", so it is likely that this dinosaur fed on the predominant plants of the era: ferns, cycads and conifers. It would have used its sharp Ceratopsian beak to bite off the leaves or needles.

Further reading

• Dodson, Peter (1998). "Monoclonius—The First Ceratopsid". The Horned Dinosaurs. Princeton, New Jersey: Princeton University Press. pp. 127–169. ISBN 0-691-05900-4. OCLC 60183976.