Tag Archives: DomeHeaded

New Dome-Headed Dinosaur Species Discovered in Montana

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A new genus and species of pachycephalosaur dinosaur has been identified by paleontologists from five fossil specimens found in the Late Cretaceous Two Medicine Formation in Montana, USA.

Reconstructing the life of Brontothorus harmony. Image credit: Connor Ashbridge / CC BY 4.0.

This newly identified dinosaur roamed North America during the late Cretaceous period, approximately 75 million years ago.

Named Brontothorus harmony, this ancient herbivore measured around 3 meters (10 feet) in length.

It is classified within the Pachycephalosauridae, a family of bipedal, dome-headed dinosaurs belonging to the ornithischian clade Pachycephalosauria.

“Pachycephalosaurs are a unique ornithischian clade characterized by distinct morphological features,” stated paleontologist D. Carey Woodruff, Ph.D., from the Philip Patricia Frost Museum of Science and the Museum of the Rocky Mountains, along with colleagues.

“These traits include bipedalism, heterodentary dentition, ossification of the caudal muscular septum, as well as the distinctive thickened frontoparietal dome and decorated skull.”

“Most pachycephalosaurid species are primarily known from cranial remains, making the anatomy, functional morphology, and phylogenetic significance of the frontoparietal dome particularly intriguing for paleontologists.”

“This clade is exclusively identified from Late Cretaceous Asia and western North America, with the latter showcasing a more diverse assemblage of pachycephalosaur species.”

“The oldest North American species is the Santonian variant, Acrotorus odeti, and this group evidently diversified during the middle to late Campanian period, resulting in a wealth of presently recognized species.”

A total of 5 specimens attributed to Brontothorus harmony were unearthed in the Two Medicine Formation located in Glacier County, Montana.

“This new species represents the first pachycephalosaur discovered from the Two Medicine Formation,” the paleontologists noted.

The notable dome structure of Brontothorus harmony positions it as the third largest pachycephalosaur in North America.

“Phylogenetic analyses indicate that this new species is significantly distinct from both Stegoceras and Pachycephalosaurus,” the researchers remarked.

“Thus, this species is not closely related to Stegoceras or Pachycephalosaurus.”

“This discovery not only enhances our understanding of the morphology and diversity of pachycephalosaurs but also highlights that this clade included relatively large species sizes during the early Middle Campanian.”

The finding of Brontothorus harmony is detailed in a paper published on October 9, 2025, in the Zoological Journal of the Linnean Society.

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D. Cary Woodruff et al. 2025. The first pachycephalosaurs from the Late Cretaceous Two Medicine Formation: Influence of the Western Interior Seaway on the evolution of North American pachycephalosaurs. Zoological Journal of the Linnean Society 205 (2): zlaf087; doi: 10.1093/zoolinnean/zlaf087

Source: www.sci.news

Discovery of a New Pakisephalosaur Species: A Dome-Headed Dinosaur Unearthed in Mongolia

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Paleontologists have unearthed fossilized remains of a previously unknown species of pachycephalosaur in the Gobi Desert, Mongolia. These fossils are the most complete and geologically oldest Pachycephalosaurus specimens discovered worldwide.

A young zavacephale rinpoche engaged in a territorial duel along the shores of a lake 108 million years ago. Image credit: Masaya Hattori.

“The Pakisepalosaurus, akin to the dome-headed dinosaurs, is one of the most intriguing dinosaurs,” states Dr. Tsogtbaatar Chinzorig, a researcher affiliated with the Mongolian Academy of Sciences and the Institute of Paleontology at North Carolina State University.

“It is thought that members of this group, characterized by their enlarged skull roofs and intricate skull features, developed a complex social structure.”

“Despite their crucial role in comprehending dinosaur behavioral ecology, the absence of uncontested early species has hindered our understanding of their origins and the reconstruction of early evolution.”

This new pachycephalosaur species has been named zavacephale rinpoche, which thrived in Mongolia during the early Cretaceous period, approximately 108 million years ago.

During this period, the region was a valley adorned with lakes and flanked by cliffs and wetlands.

“zavacephale rinpoche predates the known Pakisepalosaur fossils by about 15 million years,” Dr. Chinzorig notes.

“It was a small creature, measuring less than 1 meter (3 feet) in length, yet it stands as the most complete specimen discovered to date.”

Fossilized remains of zavacephale rinpoche were found in the Klen Duk Formation within the East Gobi Basin.

“zavacephale rinpoche represents a vital specimen for deciphering the evolution of the Pachycephalosaurus’s cranial dome. This has been a topic of debate for quite some time, given the lack of early divergent or pre-rear Cretaceous species and the fragmentary nature of most Pachyphalosaurus fossils,” Dr. Chinzorig explained.

“We’ve encountered many unique experiences worldwide,” remarked Lindsay Zanno, a researcher at North Carolina State University and director of paleontology at the North Carolina Museum of Natural Sciences.

“The domes likely provided no defense against predators or help in thermoregulation; thus, they were probably a means of display for social interactions.”

“If you seek to establish a relationship, I suggest starting your rehearsals early,” she adds.

zavacephale rinpoche fills a significant gap in the timeline of Pachycephalosaurs.

“This specimen is a unique discovery,” Dr. Zanno emphasized.

“Not only does it push the fossil record of this group back by at least 15 million years, but it is also the oldest and most well-preserved Pachycephalosaurus known, offering profound insights into its anatomy and biology, including the use of gastroliths to aid in digestion.”

“The newly recovered materials from zavacephale rinpoche are helping to reconstruct our understanding of the paleobiology, locomotion, and anatomy of these enigmatic dinosaurs, including aspects of their hands, gastroliths, and the articulated tails with preserved tendons,” Dr. Chinzorig concluded.

The findings are detailed in a study published today in the journal Nature.

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T. Chinzorig et al. A dome-shaped Pakisephalosaurus from Mongolia’s early Cretaceous period. Nature Published online on September 17th, 2025. doi:10.1038/s41586-025-09213-6

Source: www.sci.news

The Earliest Known Dome-Headed Dinosaurs of Mongolia

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Artistic representation of the pachycephalosaur Zavacephale rinpoche

Masaya Hattori

A dinosaur with a dome-shaped head, discovered in Mongolia, boasted a mouth full of formidable teeth and an unusually large eye socket on its skull.

The newly identified species, named Zavacephale rinpoche, roamed the Earth during the early Cretaceous period about 108 million years ago. It belongs to a group known as the Pachycephalosaurs. These dinosaurs were characterized by their dome-like skulls, which may have served defensive purposes or been used for social and mating displays.

Paleontologists exploring the Gobi Desert of Mongolia report having uncovered a fossilized skull protruding from the rocks, likening it to a “cabochon gem.” Lindsey Zanno from the North Carolina Museum of Natural Sciences stated, “This is how we came up with the species name Rinpoche, which translates to ‘precious things’ in Tibetan.”

Z. rinpoche represents the most complete specimen of its kind discovered to date, being about 15 million years younger than other known Pachycephalosaur species. It includes nearly the entire skull and limb bones, significant portions of the vertebrae, and pelvic bones. Additionally, the team was able to recover hand bones and gastroliths, which were likely used to grind food.

The dome of the fossil shows distinct dimples, possibly indicating other unidentified features of the head.

“The skull of Pachycephalosaurs is quite striking,” says Zanno. “They not only feature domes, but also bone spikes and nodes surrounding their skulls for aesthetic purposes. These embellishments served as sort of decorative accessories for the dome.”

Skull of Zavacephale rinpoche

North Carolina Museum of Natural Sciences

To ascertain the age at which the dinosaur perished, researchers examined thin slices of the bones from its lower limbs. They classified it as a “teenager,” measuring approximately one meter in length and weighing just under six kilograms. It remains uncertain how large it might have become as an adult, though other members of its group reached lengths exceeding four meters and weights around 400 kilograms.

“The preserved tissues show two growth rings, suggesting that it was actively growing at the time of its death,” noted Zanno. “The spinal bones exhibit no signs of wear, indicating room for further growth.”

CT scans of the skull dome revealed it was fully developed, emphasizing its significance at a younger age.

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Source: www.newscientist.com