Dome-headed dinosaur from Mongolia is the oldest ever found

An extraordinary dome-headed dinosaur uncovered in Mongolia, Zavacephale rinpoche, possesses astonishing features, including a formidable array of teeth and significant eye sockets reminiscent of cartoon characters.

This newly identified species existed approximately 108 million years ago during the early Cretaceous period, categorizing it as part of the pachycephalosaurs—dinosaurs recognized for their solid bone domes atop their skulls, presumed to be utilized for defense or in social interactions.

According to paleontologists who excavated the fossil in Mongolia’s Gobi Desert, the skull fragment rose from the sediment like a precious cabochon gem. Lindsay Zanno from the North Carolina Museum of Natural Sciences remarked, “Hence, we chose the name rinpoche, meaning ‘precious one’ in Tibetan.”

Z. rinpoche emerged 15 million years earlier than prior known pachycephalosaur species and is the most complete specimen identified to date, comprising nearly the entire skull, traits of limb bones, and significant sections of its vertebral column and pelvic region. Additionally, the researchers discovered hand bones and gastroliths, stones that the dinosaur would have used to aid in processing its food.

The fossilized dome exhibits a textured surface with dimples, suggesting the potential presence of additional, unidentified head characteristics.

“The skulls of pachycephalosaurs are visually striking,” states Zanno. “They showcase not only domes but also bony spikes and nodes around their skulls that are believed to enhance visual display—essentially splendid accessories for their domes.”

To gauge the dinosaur’s age at the time of its demise, researchers created a thin section of its lower leg bone, revealing that it was a “teenager,” measuring roughly one meter in length and weighing almost 6 kilograms. While the precise adult size remains uncertain, it is known that some pachycephalosaurs attained lengths exceeding 4 meters and weights up to 400 kilograms.

“The tissue analysis indicates the presence of two growth rings, confirming that the creature was still in an active growth phase at the time of its death,” explains Zanno. “Moreover, the vertebrae remain unfused, which indicates an ability for further growth.”

CT scans of the dome reveal that its structural integrity was well-established, highlighting that even at a juvenile stage, this trait was significant, emphasizing its potential role in the dinosaur’s life.