A new, spectacularly adorned dinosaur has been named from Montana, and it’s part of a rapidly evolving story that demonstrates strong region-specific evolution in this group of giant herbivores.
Named Lokiceratops rangiformis by Mark Loewen and colleagues in the open access journal PeerJ, the new dinosaur is a ceratopsid – a four-legged, horned plant-eater akin to Triceratops – from 78 million years ago in the Late Cretaceous.
Ceratopsids are famous for the bony frill that projects backwards and upwards from the rear of the skull as well as for their nose and brow horns.
Lokiceratops lacks a nose horn entirely, has a pair of asymmetrical spikes on the frill midline, and a pair of gigantic, curved, blade-like spikes on the frill’s upper edge.
“This new dinosaur pushes the envelope on bizarre ceratopsid headgear, sporting the largest frill horns ever seen in a ceratopsid,” said team member Joseph Sertich of the Smithsonian Tropical Research Institute and Colorado State University.
The new dinosaur’s name credits the horned god Loki of Norse mythology and also makes a nod to the ornate anatomy of reindeer, meaning ‘Loki’s horned face, resembling a caribou’.
The single Lokiceratops specimen was discovered in the rocks of the Judith River Formation in the badlands of Kennedy Coulee in Montana, close to the US-Canada border, in 2019.
Montana in the time of Lokiceratops looked very different from today. Tropical swamps and forests covered a continent, termed Laramidia, that extended from Mexico to Alaska. A warm, shallow sea separated Laramidia from landmasses to the east.
In terms of its placement in the ceratopsid family tree, Lokiceratops is a centrosaurine, and thus close to short-frilled, deep-nosed Pachyrhinosaurus and spiky-frilled Styracosaurus. This makes it the latest addition to a cast marked by a surprising increase in diversity.
In 1990, scientists recognised just eight centrosaurine species, whereas around 30 are known today. Their family tree has gone from sparse and simple to complex, with numerous branches.
Lokiceratops belongs to the newly named Albertaceratopsini, a group whose members possess hook-shaped spikes on the top edge of the frill and long, widely divergent brow horns. They were generally around 6 m (20 ft) long as adults.
Another point that Lokiceratops reinforces is that several centrosaurine species inhabited the same community, since it lived alongside at least three others. All differed in the anatomy of their horns and frills.
So far as we know, these animals were highly endemic, meaning that they were unique to a relatively small geographical area. “The endemism present in centrosaurines is greater than in any other group of dinosaurs," said University of Utah team member Savhannah Carpenter.
If this high endemism was true of centrosaurines in northern Montana, it could have been true of other places where this group occurred. And a broader consequence of this is that centrosaurine diversity as whole, and even Cretaceous dinosaur diversity as a whole, could have been underestimated.
Artwork: Reconstruction of Lokiceratops in the 78-million-year-old swamps of northern Montana, USA. Credit: Sergey Krasovskiy for the Museum of Evolution in Maribo, Denmark
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