A new dome-headed dinosaur discovered in Big Bend, Texas, is one more reason to believe that North America was once a hotbed of dinosaur diversity.

Nick Longrich, a postdoctoral associate in the Geology and Geophysics Department, announced the discovery of Texacephale Langstoni in an article in the April issue of the journal Cretaceous Research. The dinosaur’s discovery, Longrich said, further proves that many dinosaur species were exclusive to certain regions.

Longrich said his colleagues had discovered the specimen in 2008 and contacted him because of his previous work with fossils of similar-looking dinosaurs who lived in Montana and Canada.

“Nobody knew what the hell this thing was,” Longrich said. “It looked like rocks and was covered by a layer of crud.”

Someone had unearthed the fossil in the 1930s and had left it exposed, he said. Longrich flew out to Texas to examine the fossil and found another specimen in poor condition a quarter of a mile away from the first.

Longrich proceeded to compare these specimens to fossils he had previously studied and eventually concluded it was a new species. The Texacephale Langstoni (Texacephale means “Texas-head,” while “Langstoni” refers to prominent American paleontologist Wann Langston) was about as large as a medium-sized dog, ran on two legs, lived about 70 to 80 million years ago and was a plant eater.

The dinosaur’s most remarkable feature was its great domed head, caused by the fusion of four bones to make a helmet-like skull three inches thick.

Bone that thick is impressively strong, Longrich said. Authorities detained Longrich and his colleagues when they attempted to board a flight with the skull, thinking that it could be a weapon used to break an airplane window.

Longrich hypothesized that the dinosaur used the dome to ram others of its species, likening the practice to that of big-horned sheep and musk-oxen. He said he did not see how the bone mass could have served any other purpose.

Longrich said he believed this discovery will provide insight into a larger group of North American “helmeted” dinosaurs. He theorized that helmeted dinosaurs probably evolved in North America and then moved into Asia. But the Texacephale Langstoni differs distinctly from the Montana and Canada fossils Longrich has studied.

“We retraced the evolutionary tree and this thing is really close to the base of the tree,” he said.

Longrich said he hopes to travel to the Canadian tundra near the Arctic Circle in the next year to find similar fossils.

The other authors of the paper were California State University, Stanislaus researcher Julia Sankey and Darren Tanke of the Royal Tyrrell Museum in Canada’s Alberta province.