New Dinosaur Species Discovered In Western Montana

A new dinosaur species discovered in western Montana is offering fresh insight into the state’s ancient past. Paleontologists with the Museum of the Rockies announced the identification of Brontotholus harmoni, a dome-headed dinosaur found in the Two Medicine Formation and dated to roughly 75 million years ago.

The 10-foot-long pachycephalosaur is the first of its kind documented in that formation, adding another species to the diverse roster of Late Cretaceous dinosaurs that once lived on the northern Great Plains.

The discovery highlights how much remains to be learned from Montana’s fossil-rich terrain. Pachycephalosaurs are known for their thick, domed skulls, which researchers say may have served roles in display, species recognition or intraspecific combat.

The new specimen helps clarify how ecosystems evolved as the Western Interior Seaway receded and upland environments expanded. Despite decades of work in the region, scientists say finds like this show the state continues to produce meaningful paleontological insights.

Although Brontotholus harmoni was not found on land managed by Montana Fish, Wildlife & Parks, the agency used the announcement to emphasize its long-running partnership with the Museum of the Rockies.

Through an established agreement, the museum conducts paleontological research on many FWP properties. Each summer, museum staff lead a multi-week field school in Makoshika State Park, drawing participants from around the world and generating new data about the park’s fossil resources.

The museum also houses significant paleontological remains recovered from FWP lands, including specimens of hadrosaurs and tyrannosaurs displayed in its galleries. FWP’s Heritage Program regularly consults museum specialists to evaluate project impacts on fossil resources, as required under state law.

FWP staff members often encounter fossils during routine work. The agency encourages employees to report finds to the Heritage Program, noting that even a quick photo and location description can help document a discovery that may hold scientific value.

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The formal description of Brontotholus harmoni was published this month in the Zoological Journal of the Linnean Society, offering researchers and the public a deeper look into one of Montana’s latest contributions to paleontology.