Paleontologists have identified a new genus and species of centrosaurine dinosaur from fossils discovered in the Judith River Formation in the Kennedy Coulee region of Montana, USA. Lociceratops rangiformisThe new species emerged at least 12 million years earlier than its better-known relatives. Triceratops It was the largest ceratopsid of its time.

Lociceratops rangiformis It lived in what is now Montana during the Cretaceous period, about 78 million years ago.

This species was about 6.7 metres (22 feet) long and weighed five tons, making it the largest dinosaur in the group called ceratopsians. Centrosaurinae It has never been found in North America before.

“In the dinosaur ecosystem of the ancient island continent Laramidia, ceratopsians were geographically widespread, morphologically diverse and possessed a great deal of variation in cranial ornamentation, including horns and a morphologically diverse parietal scaly frill,” said Professor Mark Loewen of the University of Utah and his colleagues.

“Two distinct lineages within the Ceratopsidae family diverged by at least 83 million years ago.”

“These are the chasmosaurinae, which have long snouts and long frills, and the centrosaurines, which have rounded snouts and relatively short frills.”

“Centrosaurinae represent an ecologically important and diverse lineage of ceratopsians that reached a peak in diversity during the Campanian, 83 to 70 million years ago.”

“Historically known from abundant fossil finds in Alberta, Canada, and Montana, USA, discoveries over the past two decades have rapidly expanded our understanding of this group, particularly its geographic and morphological range, and have also provided new insights into the ontogeny of centrosaurines.”

“Centrosaurinae were locally abundant in some areas of southern Alberta and northern Montana, but were previously rare or poorly known in other parts of Laramidia.”

Fossil skull Lociceratops rangiformisImage courtesy of the Evolution Museum, Maribo, Denmark.

Paleontologists have discovered the skeleton of a mature individual. Lociceratops rangiformis Quarrying at Loki Quarry in 2019 Judith River Formation.

“The Loki quarry, which yielded the new specimen, is located on private land in the Kennedy Coulee Badlands, north of the town of Rudyard in Hill County, northern Montana, USA,” the researchers said.

Lociceratops rangiformis It has the largest frill horns of any ceratopsid ever, and lacks the nasal horns characteristic of its genus.

“This new dinosaur pushes the boundaries of outlandishness in ceratopsian head ornaments, boasting the largest frill horns ever seen on a ceratopsian,” said paleontologist Joseph Sertich of Colorado State University.

“These skull ornaments provide another window into the diversity of horned dinosaurs and demonstrate that evolutionary selection for flashy displays contributed to the dazzling richness of Cretaceous ecosystems.”

“We think dinosaur horns were similar to the displays performed by birds, who used them for mate selection and species recognition.”

Lociceratops rangiformis It coexisted with three other centrosaurine dinosaurs (Wendiceratops pinhornensis, Albertaceratops nesmoiand Medusaceratops Loki) and Chasmosaurinae (Judiceratops tigris).

“The combination of five species is an unprecedented diversity and resembles the range of horned ungulates found on the plains of East Africa today,” Dr Sertich said.

“Unlike the wide-ranging large wild mammals, such as elk, that currently roam the American West, these ancient animals were geographically restricted.”

“discovery Lociceratops rangiformis “It provides evidence that these species evolved rapidly within a small area, a process sometimes seen in birds.”

“at that time Triceratops By the time ceratopsians emerged 12 million years later, regional differences had homogenized to just two species found across Canada and Mexico, probably as a response to a more homogenous climate.”

“This study shows that dinosaur diversity has been underestimated and presents the most complete ceratopsid family tree to date.”

“Lociceratops rangiformis “This study helps us understand that we're only just scratching the surface when it comes to the diversity and relationships of the ceratopsian family tree,” Prof Loewen said.

of study Published online in the journal Peer J.

_____

M.A. Rowen others. 2024. Lociceratops rangiformis A new genus and species (Ceratopsia: Centrosaurinae) from the Campanian Judith River Formation of Montana reveals the rapid regional dispersal and extreme endemism of centrosaurinae dinosaurs. Peer J 12: e17224; doi: 10.7717/peerj.17224