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New Dome-Headed Dinosaur Discovered in Montana Fossils

10/22/2025

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Summary

Story summary

Researchers have discovered Brontotholus harmoni, a new dome-headed dinosaur species, from fossils in Montana.
The dinosaur belongs to pachycephalosauridae and lived about 75 million years ago in the Late Cretaceous.
Five specimens were found in the Two Medicine Formation, making Brontotholus harmoni the first pachycephalosaurid from this period in the region.
The species measures 10 feet long and is the third-largest pachycephalosaurid in North America, expanding knowledge of the group.

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Story summary

Researchers have discovered Brontotholus harmoni, a new dome-headed dinosaur species, from fossils in Montana.
The dinosaur belongs to pachycephalosauridae and lived about 75 million years ago in the Late Cretaceous.
Five specimens were found in the Two Medicine Formation, making Brontotholus harmoni the first pachycephalosaurid from this period in the region.
The species measures 10 feet long and is the third-largest pachycephalosaurid in North America, expanding knowledge of the group.