The mighty Triceratops has always captivated young and old alike. His three massive horns and magnificent crowned frill make him a favorite for many dinosaur lovers. What many people might not realize is that the Triceratops is only one of several species of ceratopsians that have been discovered, and certainly among hundreds that have evolved throughout prehistoric times. In 2010, a new Canadian bone bed was being excavated, and over the course of four years several specimen were uncovered. The most astonishing part was that a species of ceratopsian entirely unknown to science came with it. An article published this year in PLoS ONE describes the discovery of the dinosaur. Wendiceratops pinhornensis was the name given to this animal after her discoverer (meaning Wendy’s horned-face), and this dinosaur certainly opened up new ideas about the ceratopsian family.
It might help to first clarify a few background things on the ceratopsians. To begin with, of the two major types of all dinosaurs, ceratopsians are among the herbivorous ornithischian dinosaurs. This means they are “bird-hipped” and have a hip shape similar to that of modern birds (but are not the ancestors of birds). Ceratopsian is a name given to the rhino-like horned dinosaurs with large neck frills, although there are a few exceptions to this rule. These ceratopsians immediately divide into two new subfamilies: the centrosaurines and the chasmosaurines. These are the two types of ceratopsians paleontologists classify the horned dinosaurs into when they uncover a new species. The main difference between the two subfamilies has to do a lot with the structures of the horns and the crests. The chasmosaurines, the family that the Triceratops belongs to, has extended frills and very long, prominent horns on the nose and or on the brows. The centrosaurines, the family that this new Wendiceratops belongs to, is known for shorter or cropped frills with more horn decoration along the edges of the frill itself instead of the brows. Generally, the centrosaurines also have much smaller nasal horns, or ones that do not form a horn shape at all but instead a hard mass of bone. As far as evolution goes centrosaurines evolved earlier than the chasmosaurines by a few millions years. Centrosaurines evolved around 79 Myr ago while the chasmosaurines evolved 75 Myr ago. Knowing these basics, it makes it easier to grasp the significance of the discovery of Wendiceratops.
When the bones were excavated not much of Wendiceratops was thought to be in the bone bed. As excavation continued for the next few years more and more of her was uncovered. By the end of the dig a large portion of her skeleton was recovered. Dinosaur fossils are usually never found 100% complete, so finding even 25% of a skeleton can be quite significant, which is about how much was discovered of Wendiceratops. Some specimens of dinosaurs are only named from one bone! Fortunately, enough of Wendiceratops was uncovered to identify her as a new species. This was mainly because large chunks of the skull were found with unique frill ornamentation. The horns or spikes at the top of the frill unusually curled over and back onto the frill. This wasn’t a defect from being preserved, it’s how the bone spikes grew as the animal matured as is even seen in other ceratopsians, such as Vagaceratops. In reconstruction it was assumed that the animal had brow horns because of a skull structure similar to that of other ceratopsians that had such features. The nasal horn was only partially found, and it is assumed that it would have had a sloped or blunted end almost as if cut in half compared to the nasal horn of Triceratops.
The new dinosaur, excavated in the Oldman Formation of Alberta, was an extraordinary discovery once paleontologists including Wendy Sloboda & Ryan Evans realized her age. Wendiceratops is about 79 million years old, making her one of the oldest ceratopsians ever discovered. She lived during the Campanian Age, which is part of the late Cretaceous period. At the end of the Cretaceous almost all dinosaur species were wiped out. ceratopsians were just beginning to diversify during this time and it is rare to find such a well adorned animal. This nasal horn fragment that was discovered on Wediceratops also suggests that the horn itself evolved independently twice in ceratopsian evolution. This basically means that two species of ceratopsians who are not closely related both grew horns on their noses without relying on previous evolution of the horn to do so. It was mentioned earlier that the centrosaurines, the subfamily that Wendiceratops belongs to, evolved about 79 Myr ago in the late Cretaceous. This was data taken from dinosaurs discovered previously to Wendiceratops. Only two other species of centrosaurines had been discovered that lived during this time period. Those were the Diabloceratops at 80 Myr ago and the Xenoceratops at 79 Myr ago. Wendiceratops fills in the gap between the two, aging slightly older than the aforementioned Xenoceratops. When reconstructing the cladograms of the ceratopsians it was found that Wendiceratops was actually most closely related to an asian species of ceratopsian, suggesting that the species may have migrated from what is now Asia to North America or vice versa. The horn structure also shows development of the ornamentation with these animals that is far more intricate than originally thought. With her included, it adds another incredibly helpful link in the chain of evolution for these dinosaurs.
Wendiceratops pinhornensis is an amazing new discovery to add to the paleontological world. As with many dinosaur excavations it didn’t come without time-consuming work and bones that are few and far between. Despite that, what was uncovered amazed scientists. The dating of these bones back to 79 Myr ago furthered the completion of the family tree of ceratopsians, especially in the subfamily of the centrosaurines. This new dinosaur proved that the diversifications of these horned beasts was widely varied and that evolution took place quite rapidly between new species. In the span of a few million years the centrosaurines took on completely different appearances physically, which is not an easy feat. This discovery will hopefully lead not only to more bone beds being uncovered, but also to furthering our understanding of how dinosaurs evolved, adapted to their environments, and interacted with each other.
For those of you who want more, check out this video made by the Cleveland Museum of Natural History!
Evans DC, Ryan MJ. Cranial Anatomy of Wendiceratops pinhornensis gen. et sp. nov., a centrosaurine Ceratopsid (Dinosauria: Ornithischia) from the Oldman Formation (Campanian), Alberta, Canada, and the Evolution of Ceratopsid Nasal Ornamentation. 2015 Jul 8 [cited 2015 Aug 8]; 10.1371/journal.pone.0130007.
Prostak S. Wendiceratops: New Genus and Species of Horned Dinosaur Discovered in Canada [Internet]. 2015 Jul 9; [12 paragraphs].