Sierraceratops turneri: New Horned Dinosaur Species Identified in New Mexico

Wednesday, October 6, 2021

Life reconstruction of Sierraceratops turneri. Image credit: Sergey Krasovskiy.

A new genus and species of chasmosaurine ceratopsid dinosaur has been identified from skeletal fragments found in the Late Cretaceous rocks of the Hall Lake Formation in south-central New Mexico, the United States.

The newly-identified dinosaur roamed the ancient island continent Laramidia some 72 million years ago (Late Cretaceous period).

It had an ornate frill, short but massive brow horns, a 1.5-m (5-foot) long skull, and was about 4.6 m (15 feet) in length.

Named Sierraceratops turneri, it belongs to a subfamily of ceratopsid dinosaurs called Chasmosaurinae.

It was a sister species to the ceratopsid dinosaurs Bravoceratops and Coahuilaceratops, part of a group endemic to the southwestern United States and Mexico.

It is also related to but predates the famous ceratopsid dinosaur Triceratops by some 6 million years.

Sierraceratops turneri is most closely related to other ceratopsids from Texas and northern Mexico,” said Dr. Nick Longrich from the Milner Centre for Evolution at the University of Bath and colleagues.

“These dinosaurs form a group that lived only in southwestern North America, different from the ceratopsid groups that lived to the north.”

“This suggests that distinct and endemic dinosaurs may have inhabited different parts of western North America during the Late Cretaceous, 72 million years ago.”

“Part of the reason dinosaurs became so diverse is that they would specialize on different habitats, just like modern birds or mammals,” Dr. Longrich said.

“These are huge animals, and you’d think they would be widespread. But in fact, it’s not the same species living everywhere.”

“Different species probably adapted to the local climate, plants, predators, and diseases giving them an edge against invaders from outside.”

“We have known of Cretaceous dinosaurs in New Mexico and the Southwest for more than a century, but for most of that time our knowledge of the diversity of this dinosaur fauna has lagged behind our understanding of the dinosaurs of the northern Great Plains from Wyoming to Alberta,” said University of Pennsylvania’s Professor Peter Dodson, who was not connected with the study.

The partial skeleton of Sierraceratops turneri was found in the 1990s on the ranch of Ted Turner, founder of the Cable News Network (CNN).

Sierraceratops turneri was collected from a layer of rocks that has been understudied as far as its fossils and dinosaur fauna,” said Harrisburg University’s Dr. Steven Jasinski.

“When we spend more time researching and collecting in understudied strata like this, we find that different rocks often have distinct dinosaurs, and these dinosaur communities are frequently unique, particularly if they are from different times or ages.”

According to the paleontologists, Sierraceratops turneri adds to the diversity and disparity of Chasmosaurinae in the Late Cretaceous and provides additional evidence for Laramidian endemism.

“Together with the new species, the Hall Lake Formation dinosaur fauna suggests that the latest Cretaceous of southern Laramidia was characterized by endemic clades and distinct community structures,” they said.

The findings appear in the journal Cretaceous Research.


Sebastian G. Dalman et alSierraceratops turneri, a new chasmosaurine ceratopsid from the Hall Lake Formation (Upper Cretaceous) of south-central New Mexico. Cretaceous Research, published online September 29, 2021; doi: 10.1016/j.cretres.2021.105034