Reindeer of the Cretaceous: Bladelike horned dinosaur rewrites prehistoric playbook

New findings, whether from rocks or overlooked museum collections, urge scientists to refine the dinosaur family tree continuously. But, according to University of Edinburgh paleontologist Stephen Brusatte, their sheer number could surpass our wildest expectations. “Today, about 14,000 dinosaur species live on as birds,” Brusatte said. “Do the math and we’re probably talking about millions of dinosaur species that once lived, maybe tens of millions.”

A study published in the journal PeerJ in June describes one captivating addition to this ever-growing tree. This newly discovered species, notable for its impressive size and distinctive horn structure, represents a significant addition to the ceratopsid family.

The discovery

The fossils of Lokiceratops rangiformis, a four-legged, horned herbivore that preceded the Triceratops by 12 million years, was found in northern Montana, near the US-Canada border in 2019.

Identified and named by Joseph Sertich, PhD, from Colorado State University, and Mark Loewen, PhD, from the University of Utah, it is estimated to have lived around 78 million years ago during the Late Cretaceous period.

In an interview with Interesting Engineering, the two scientists recounted the thrilling moment of discovery. Through careful reconstruction and comparison, the researchers realized they had uncovered a previously unknown species.

“We started working on the fossil in 2022, and we assumed it was one of the four other dinosaur species from the same rock layer,” Sertich told IE. “We thought it was a large adult individual of Medusaceratops, but once we started to lay these fossils out and piece the skull back together, we had this Eureka moment: that this was its own separate species based on the shape, size, and pattern of the horns of the face.”

Loewen emphasized how exceptionally rare it is for five-horned dinosaurs to coexist in the same place. “This is like going to Africa and finding five different species of elephants living in the Savannah; we wouldn’t expect that,” Loewen added. “These animals are actually elephant-sized individuals, and they are all herbivores, so we had to start thinking about what allows these different species to coexist, a pattern we wouldn’t expect in modern herbivores.”

Uncovering the details

Lokiceratops, measuring 22 feet long and weighing 11,000 pounds, distinguishes itself from other ceratopsids by its unique horn structure. While most ceratopsids feature a bony frill and nose and brow horns, Lokiceratops notably lacks the typical nose horn of its relatives.

Instead, it boasts a pair of asymmetrical spikes along the frill’s midline and a set of large, curved, blade-like spikes on the frill’s upper edge, something the scientists had never seen before.

“When you think of the majority of horned dinosaurs, you think of Triceratops, it’s got a horn above each eye, and a horn above its nose,” Loewen said. “Our animal lacks the horn above the nose, so that’s another feature that suggests to us this animal is definitely different.”

To confirm their theory, the paleontologists traveled the globe, comparing the bones with those of other ceratopsids.

“We’ve looked at specimens in Europe, all across North America, and in China, to make sure that the variation we are seeing in this animal wasn’t a variation as the animal grows up or one between sexes,” Loewen explained. “So looking at it, we are actually quite convinced that the pattern of the ornaments on the back of this animal is completely different than in any other dinosaur.”

The dinosaur’s name honors the Norse god of mischief while referencing the intricate anatomy of reindeer. “The dinosaur now has a permanent home in Denmark, so we went with a Norse god, and in the end, doesn’t it just really look like Loki with the curving blades,” Loewen said.

To that, Sertich added, “The second name means ‘like a caribou’ or ‘like a reindeer.’ This horned dinosaur has asymmetric horns in the middle of its frill, a lot like the antlers of a caribou, which are in the middle of the face.”

What’s next?

With over 80 percent of the skull reconstructed, the two scientists are confident they clearly understand what Lokiceratops was like. “We think that the horns on these dinosaurs were analogous to what birds are doing with displays,” Sertich says. “They’re using them either for mate selection or species recognition.”

The next step, say the scientists, is to finish describing the rest of the dinosaurs from the same deposit, name them, and then compare them. “As we find more and more specimens, we are trying to build a clear picture of the family tree of the ceratopsians, which eventually led to Triceratops,” Loewen said. “And we want to understand how they evolved in their world.”

The researchers believe such a diversity of similar animals living together at one time suggests that they underwent rapid evolution.

“This discovery shows that we’re really just scratching the surface of dinosaur diversity at this time period,” Sertich added. “This is the first time where we have five horned dinosaurs living together, but this isn’t the only place where we’re starting to see that, so this is becoming more of a pattern, rather than an exception.”

“This is important because it tells us a lot about diversity and patterns of evolution, at a time when global temperatures were much higher when the tropics and subtropics reached farther north,” Sertich concluded. “So we can learn a lot about how evolution works in a dynamic world, as it teaches us a lot about what we should expect during our future as things change rapidly.”

The original fossil is on permanent display at the Museum of Evolution in Maribo, Denmark, while a replica is showcased at the Natural History Museum of Utah.