Monoclonius: Cretaceous Ceratopsian

Monoclonius was an early ceratopsian dinosaur (related to triceratops) that lived in the late Cretaceous Period in North America. Fossilized remains of monoclonius have been found in areas of Montana and Alberta, particularly in fossil-rich badlands.

Monoclonius was shaped like other ceratopsians, with small legs, a short, stocky tail, a tank-like body and a huge head. It was probably not very fast moving judging by its small legs and bulky body. However, like most ceratopsians, it sported impressive biological defenses. It had a thick hide that carnivores would have found difficult to bite through and also a bony frill flanking its gigantic head that would have helped to protect its eyes and other vulnerable areas. The frill was probably also used in mating rituals, since male frills were larger than female frills. Unlike other ceratopsians like triceratops and torosaurus, monoclonius only possessed a single curved horn pointing upward from its nose. This horn could have deterred carnivores from attacking its face and also could have been used as a stabbing weapon with some effect. Contrary to popular belief, the name "monoclonius" does not mean "single horn" but rather "single root." The root in this case refers to the animal's teeth which contained a single root. Why its discoverers would have made a reference to this when naming instead of the characteristic single horn is beyond me.

Like all other ceratopsians, monoclonius was a herbivore, feeding on low-hanging plants that were plentiful during the Cretaceous such as cyads, conifers, and ferns. It possessed a hooked beak, akin to that of a parrot which helped to snip off vegetation which was then ground up with specialized cheek teeth. It is unlikely that monoclonius fed on many flowering plants (angiosperms) because they were not widespread in North America as yet. These dinosaurs may have banded together in herds like other large herbivorous dinosaurs to protect their young.

Monoclonius, along with other ceratopsians were comparatively brighter than many herbivorous dinosaurs. Although nowhere near as smart as large carnosaurs like Tyrannosaurus or smaller therapods like troodon, monoclonius occupied a sort of middle ground in the intelligence arena. This has been deduced by looking at the size of its brain cavity relative to its body size. Sauropod dinosaurs had a tiny head and an enormous body and were thus not considered very intelligent, whereas humans have a very large brain and comparatively small body.

It is not clear whether monoclonius lived until the end of the Cretaceous Period or died out beforehand. What is clear is that certain ceratopsians, triceratops in particular, can trace their lineage back to this early single-horned ceratopsian.