Regaliceratops represents one of the most recent and striking discoveries among the Ceratopsidae family, the lineage of dinosaurs characterized by prominent horns and bony neck frills. This herbivorous giant roamed western North America during the Late Cretaceous period, approximately 68 million years ago. As a member of the diverse Ceratopsian order, it shared common features with relatives like Triceratops, possessing a parrot-like beak and walking on four sturdy legs. The unique morphology of its skull sets it apart, providing new insights into the rapid evolutionary changes occurring just before the close of the Age of Dinosaurs.
The Royal Horned Face: Naming and Discovery
The existence of this distinctive species was first revealed in 2005 when geologist Peter Hews discovered a near-complete skull protruding from a cliff face in the badlands of southwestern Alberta, Canada. The fossil was embedded in incredibly hard siltstone rock belonging to the St. Mary River Formation, which dates back to the Middle Maastrichtian stage of the Late Cretaceous. Hews notified the Royal Tyrrell Museum, which began the challenging excavation process.
The arduous recovery involved years of painstaking work between 2006 and 2008, complicated by the dense matrix surrounding the fossil and the proximity of the site to a protected bull trout spawning habitat in the Oldman River. This difficult excavation led the team to give the specimen the informal nickname “Hellboy,” a moniker that matched the dinosaur’s relatively small brow horns. Paleontologists Caleb M. Brown and Donald M. Henderson formally named and described the new species in 2015.
The genus name Regaliceratops translates to “royal horned face,” reflecting the crown-like ornamentation along the edge of its bony neck shield. The full species name, Regaliceratops peterhewsi, honors the geologist who first spotted the specimen. Based on the size of the recovered skull, researchers estimate this individual reached a length of about 5 meters (16 feet) and weighed between 1.5 and 2 metric tons.
Distinctive Skull Structure
The most striking feature of Regaliceratops is its elaborate cranial ornamentation, known almost entirely from its exceptionally well-preserved skull. The bony neck frill, which extended over the dinosaur’s shoulders, was semicircular, relatively short, and wide, resembling the frills found on Triceratops and Torosaurus. Adorning the perimeter of this frill was a row of seven paired bony spikes, known as epoccipitals, that gave the structure its distinctive regal appearance.
These bony plates decrease in size as they move outward from the midline of the frill. The two central epiparietals are notably large and pentagonal in shape, while the other epoccipitals transition to triangular and spade-like forms. The overall arrangement creates a flamboyant, crown-like effect that served as a visual display structure for species recognition or mating rituals.
In addition to the ornate frill, the face of Regaliceratops featured a prominent horn arrangement that defied the typical pattern for its taxonomic group. It possessed a single, robust nasal horncore, estimated to be 240 to 280 millimeters tall when reconstructed. Conversely, the two horns situated above its eyes, the postorbital horns, were noticeably reduced and stubby. This combination of a large nose horn and small brow horns is highly unusual for its subfamily. The skull also features small openings, or fenestrae, in the frill, which are a comparable size to the eye sockets themselves.
Classification and Evolutionary Context
Regaliceratops is classified within the Chasmosaurinae subfamily of the Ceratopsidae, the group that includes the long-frilled Chasmosaurus and the massive Triceratops. Ceratopsids are traditionally split into two main groups: the Chasmosaurines and the Centrosaurines, which are largely distinguished by their horn and frill architecture. Chasmosaurines are generally characterized by long frills and long brow horns coupled with a small nasal horn.
The new species presents a unique evolutionary puzzle because its cranial features appear to blend the characteristics of both groups. Specifically, its large nasal horn and short brow horns are morphological traits usually associated exclusively with the Centrosaurine subfamily. This suggests that Regaliceratops represents a late-occurring Chasmosaurine that evolved to look like a Centrosaurine, a phenomenon known as convergent evolution.
This evolutionary convergence is significant because it occurred after the Centrosaurines had largely disappeared from the North American fossil record. Researchers theorize that after the Centrosaurines vanished, the Chasmosaurines diversified to fill the ecological niche for ornate display structures. Regaliceratops demonstrates a late-stage evolutionary burst, where a member of the Triceratops lineage independently evolved the large nose horn and elaborate, spiked frill aesthetic of the earlier Centrosaurines. This discovery refines the understanding of Late Cretaceous Ceratopsian evolution.