Lokiceratops, the horned dinosaur, may be a new species

In the Late Cretaceous, a notable flourishing of horned dinosaurs occurred along the coastal floodplains of western North America. Two different families – each sporting every imaginable array of spikes, horns and frills – range across the landscape, using their headdresses to signal teammates and challenge rivals.

Seventy-eight million years later, members of that ancient abundance are still emerging, leading to a recent boom in discoveries. The latest — described Thursday by a team of researchers In PeerJ — It is Lokiceratops rangiformis, a five-ton herbivore with striking, curved forehead horns and huge bladed spines on a metre-long frill.

Researchers argue that this is a new species, and the presence of others like it suggests that the region from Mexico to Alaska was filled with pockets of local dinosaur biodiversity. However, other experts stress that there is not enough evidence to draw such conclusions based on a single set of remains.

The skull of the dinosaur in question was discovered in 2019 by a commercial paleontologist on private land in northern Montana. It was acquired by the Museum of Evolution in Maribo, Denmark.

“They saved it by buying it, so now it’s available forever for scientists to examine,” said Joseph Sertich, a paleontologist at the Smithsonian Tropical Research Institute and author of the study. “We couldn’t write a paper about a fossil sitting in a rich person’s living room and being treated as art.”

The team of researchers initially thought they were working with the remains of Medusaceratops. But when they collected parts of the shattered skull, they began to notice differences.

The animal lacked a nasal horn. The brow horns were hollow. Then there were the curved, paddle-like horns on the back of the frill—the largest ever found on a horned dinosaur—and a distinctive, asymmetrical spike in the middle.

“That’s when we started getting really excited,” said Mark Lewin, a paleontologist at the Natural History Museum of Utah and an author of the study. “Because it became clear that we had something new.”

Because the skull was destined for a museum in Denmark, the team named the animal after the Norse god Loki. “It really looks like the helmet Loki wears,” Dr. Lewin said.

Dr. Sertich said this discovery sheds light on the evolution of horned dinosaurs in North America. During the Late Cretaceous, the continent was divided in half by an inland sea. Two groups of horned dinosaurs roamed the western Laramidia subcontinent. Chasmosaurines – the family that eventually gave rise to Triceratops – tend to occur in the southern half of the Indian subcontinent, while Centrosaurines – the family to which Lokiceratops belongs – are generally found in the north.

Lokiceratops is the fourth Centrosaurine found in its Montana ecosystem.

Researchers say that remains of these species have not been found in other parts of North America, which fits a broader pattern of diversity of horned dinosaurs in the West.

“We did not find animals that lived in Canada in Utah, or animals that lived in Utah in New Mexico,” Dr. Lewin said.

The team suggests that the dynamic may have been driven by sexual selection, as different groups of female horned dinosaurs developed specific aesthetic tastes that led to explosions in the evolution of local species. In modern ecosystems, this process has led closely related birds of paradise to develop different displays while sharing ecological niches.

By the end of this period, centrosaurs had largely disappeared, and animals such as Triceratops and Tyrannosaurus rex ranged from Mexico to Canada, suggesting a more homogeneous continent, Dr. Sertic said.

“It has implications for the modern world. As the climate warms and changes, animal distributions change,” he added. “Studying past climates and ecosystems and how they interacted will impact our understanding of what could happen going forward.”

Not everyone shares this interpretation or believes that animals like Lokiceratops represent distinct species. Many ceratopsian species were based on limited remains, leading to possible overinterpretation, said Denver Fowler, a paleontologist at the Dickinson Museum in North Dakota who was not involved in the research.

The hollow brow horns found in Lokiceratops, for example, are also present in the oldest adult Triceratops, while the asymmetrical horn height on the frill could be a genetic quirk, he said.

“A lot of the features here may just be signs of a very mature Medusaceratops, and that would be the most conservative interpretation,” Dr. Fowler said.

Dr. Fowler and some colleagues favor another proposal: fewer species with more individual diversity that gradually shifted from Mexico to Alaska. He added that as more fossil remains emerge, it will become clear what the important differences are.

“It’s an amazing specimen that definitely needs to be described,” Dr. Fowler said. “It really helps us anthropomorphize the animals.”

As more remains emerge, the teams will be able to test whether Lokiceratops was its own species, Dr. Sertich said.

“I can think of eight undescribed species that are coming soon,” Dr. Lewin said. “I don’t think we have 1 percent of the diversity of true ceratopsids that lived in North America.”