New Species of Multi-Horned Dinosaur from 78 Million BC Found in Montana
A team of paleontologists has identified an impressive new species of dinosaur from fossil remains extracted from a bed of ancient bones located in the western United States, near the U.S.—Canadian border. The animal possessed a unique arrangement of distinctive horns on its head, and has been given the name Lokieceratops because of its resemblance to the Norse trickster god Loki, who is often depicted wearing a set of horns.
Lokieceratops Found to Roam Montana
The fossils that led to the discovery of Lokieceratops were recovered during explorations in 2019 in the Judith River Formation of northern Montana, which is part of the Kennedy Coulee region that connects the northern and western United States with Canada. A reconstruction of the bone fragments has revealed that the dinosaur was a modest-sized plant eater that had a set of curving, blade-shaped horns over its eyes, and a second pair of flattened, asymmetrical horns at its head plate’s peak, the latter of which resembled the horns of a caribou.
Although far from identical, similarities with the horns of a caribou have been drawn. (Bering Land Bridge National Preserve/CC BY 2.0)
The complete name of the dinosaur, which lived 78 million years ago, is Lokieceratops rangiformis , which translates to “Loki’s horned face that looks like a caribou.”
This Late Cretaceous period (99.6 million to 66 million years ago) reptile belonged to a clade (a group of species with a common ancestor) of dinosaurs known as centrosaurines, most or all of whom apparently lived within a relatively limited geographical area. This latter fact is significant, because it has helped scientists determine that the diversity of dinosaur species that lived in the lands of ancient North America was surprisingly rich.
Dinosaur Diversity Explodes in the Late Cretaceous
The team of scientists who determined that the fossils from this dinosaur came from a previously undetected species were led by paleontologists Joseph Sertich from Colorado State University and Mark Loewen from the University of Utah, who are also affiliated with the Smithsonian Tropical Research Institute and the Natural History Museum of Utah respectively.
In a new article just published in the journal PeerJ, the scientists provide a detailed description of Lokieceratops, and they also discuss the curious fact that this species and other members of its clade apparently didn’t venture very far from their point of evolutionary origin in western North America.
“The high endemism [limited territorial range] seen in centrosaurines and other dinosaurs implies that dinosaur diversity is underestimated and contrasts with the large geographic ranges seen in most extant mammalian megafauna,” the study authors wrote.
In other words, Lokiceratops and the other centrosaurines had a far more limited range than might have been expected, given their size and nutritional needs. The scientists connect this with a relatively high level of diversity of dinosaur species found in the fossil record in the lands of western North America, which suggests that dinosaurs generally filled specific ecological niches in specific regions rather than wandering broadly in search of sustenance.
As a result, there were actually many more distinct species of dinosaurs living in the lands of western North America during the Cretaceous Period than had previously been suspected, since limits on geographical range inevitably produce a more complex and diverse ecosystem.
The skull of Lokiceratops rangiformis, mounted and on exhibit at the Museum of Evolution in Maribo, Denmark. (Museum of Evolution/ COLORADO STATE UNIVERSITY)
The Painstaking Reconstruction and Identification of Lokiceratops
Over the last few years, Sertich, Leowen, and their colleagues have been carefully reconstructing the bones of the 78-million-year-old dinosaur, from piles of shattered fragments that were mostly the size of dinner plates or smaller. Fortunately, enough pieces of the skull were found to make a detailed model, from which the paleontologists were able to verify that they were looking at an adult dinosaur from an entirely new species.
At 22 feet (6.7 meters) in length and weighing 11,000 pounds (five metric tonnes), this Lokiceratops comes from a species that was the largest of the horned centrosaurine group. Its horns were longer and thicker than those of its closest relatives, and unlike them it did not have a nose horn in the middle of its face.
“This new dinosaur pushes the envelope on bizarre ceratopsian headgear, sporting the largest frill horns ever seen in a ceratopsian,” Sertich said in a Smithsonian Tropical Research Institute press release announcing the installation of a replica of the dinosaur that has just been put on display at the Natural History Museum of Utah.
“These skull ornaments are one of the keys to unlocking horned dinosaur diversity and demonstrate that evolutionary selection for showy displays contributed to the dizzying richness of Cretaceous ecosystems.”
Excavating Laramidia, the Land of the Horned Dinosaurs
The fossilized bones of Lokiceratops were one of five Late Cretaceous dinosaur species recovered from the same rock layer. This means that five species of dinosaurs were living side-by-side in the swamp lands and floodplains that lined the eastern shore of the continental island of Laramidia, an ancient land that ranged from modern-day Alaska to Mexico and included all the states and provinces of what is now western North America.
“Previously, paleontologists thought a maximum of two species of horned dinosaurs could coexist at the same place and time. Incredibly, we have identified five living together at the same time,” Mark Loewen explained. “The skull of Lokiceratops rangiformis is dramatically different from the other four animals it lived alongside.”
It would be many millions of years before the continental islands of Laramidia and Appalachia, separated by the gigantic Western Interior Seaway, would unite to form North America. Yet despite the limited land availability, dinosaur species proliferated in Laramidia (they likely did as well in Appalachia, but this is uncertain since dinosaur fossils are extremely difficult to find in the hilly and woody regions of eastern North America).
“We now recognize over thirty species of centrosaurines within the greater group of horned dinosaurs, with more like Lokiceratops being described every year,” stated study co-author Andrew Farke, who works at the Raymond Alf Museum of Paleontology in Claremont, California.
It seems that the evolutionary pressures associated with living in limited land areas had an especially big impact on horned dinosaurs. According to study lead author Mark Loewen, a new type of centrosaurine was likely appearing in Laramidia every 100,000 to 200,000 years, showing that dinosaurs were capable of evolving much more rapidly than had once been believed was possible.
Top image: Reconstruction of Lokiceratops in the 78-million-year-old swamps of northern Montana, as two Probrachylophosaurus move past in the background. Source: Artwork by Fabrizio Lavezzi © Evolutionsmuseet, Knuthenborg
By Nathan Falde
References
Loewen MA, Sertich JJW, Sampson S, O’Connor JK, Carpenter S, Sisson B, Øhlenschlæger A, Farke AA, Makovicky PJ, Longrich N, Evans DC. 2024. Lokiceratops rangiformis gen. et sp. nov. (Ceratopsidae: Centrosaurinae) from the Campanian Judith River Formation of Montana reveals rapid regional radiations and extreme endemism within centrosaurine dinosaurs. PeerJ 12:e17224 Available at: https://doi.org/10.7717/peerj.17224
