This pachycephalosaur fossil emerges like a wonderfully polished jewel : NPR

It was a cloudy morning in southeast Mongolia. Paleontologist Chinzorig Tsogtbaatar and a number of other colleagues set out by foot from their campsite to a rocky outcrop relationship again some 110 million years to the early Cretaceous.

“Then, after 15 to 20 minutes, I saw something [on the] other side of the hill,” says Tsogtbaatar. It was a vivid object of some kind. “It [didn’t] look like a rock,” he remembers. “It [was] very unusual.”

Once he received nearer, Tsogtbaatar — who now works at North Carolina State University — knew precisely what it was. A dome-shaped cranium. It turned out that Tsogtbaatar had simply found a brand new species of pachycephalosaur, a singular group of dinosaurs outlined by their thick, bony, hemispherical skulls however about which little else is understood.

In that second, “we just stopped breathing,” he says.

“This is the first definitive pachycephalosaur that’s ever been found in the early Cretaceous,” says Lindsay Zanno, additionally a paleontologist at North Carolina State University along with serving as the pinnacle of paleontology on the North Carolina Museum of Natural Sciences. “It just pops out of the fossil record with a fully developed dome, and bells and whistles on its head.”

Tsogtbaatar, Zanno, and their colleagues have launched the world to this new species in a paper printed within the journal Nature. They gave it the scientific title Zavacephale rinpoche. The phrase rinpoche is Tibetan for “precious one” and refers back to the domed cranium, which appeared out of the rockface to Tsogtbaatar that June morning like a wonderfully polished jewel.

Bones of enchantment

The new specimen is 15 million years older than what had beforehand been the oldest pachycephalosaur ever discovered. “So this dinosaur fills in a critical gap in the early evolution of this famous group of dome-headed dinosaurs,” says David Evans, a dinosaur paleontologist on the Royal Ontario Museum in Toronto who wasn’t concerned within the analysis.

After its excavation in 2019, the fossil stayed in Mongolia throughout the pandemic. Finally, in 2022, it was shipped to North Carolina for extra evaluation. Zanno says the second she first laid eyes on it, she was “enchanted.”

“Everyone just stood around the lab just holding this precious, incredible skull,” she says. “It’s just the most beautiful specimen. It’s magical.”

That domed head — made from stable bone and edged in spikes — is any pachycephalosaur’s most distinguishing function.

“Their domes are essentially indestructible,” says Zanno. “It would have been able to protect the skull against pressure or impact. And so we think that these animals were battling it out with their heads.”

Still, researchers have recognized comparatively little about these plant-eaters as a result of many of the remainder of their our bodies have not been discovered. So when the crew in Mongolia went on to excavate dozens extra bones from Zavacephale rinpoche, it turned essentially the most full pachycephalosaur skeleton ever to be unearthed.

“It’s about the size of a German shepherd,” says Zanno, “but you have to remember 75% of the body is a neck and a tail, so they’re very light. It would have only weighed about 12 pounds.”

A juvenile jewel

This little fossil has already revealed a number of new insights. The abdomen contained small stones that will have helped the animal digest its meals. The tail is shot by means of with bony tendons, which might have made it extra inflexible.

Plus, this was the primary time a pachycephalosaur’s hand bones had ever been discovered. “At first, we thought it was something it ingested instead of parts of its own body. That’s how tiny its hands were,” says Zanno.

In addition, the limb bones allowed the researchers to find out the age of the dinosaur. It was at the very least two years previous, making it a juvenile. This reveals that younger pachycephalosaurs like this one already had totally developed domes.

“Whether they were battling it out for territory or mates is something we’re not entirely sure of,” says Zanno, “but what’s clear is that whatever they were doing with those domes, they started practicing at a very young age.”

The specimen is now again house on the Institute of Paleontology of the Mongolian Academy of Sciences as a part of the nation’s mission to guard its pure and cultural heritage.

Cary Woodruff, a curator of vertebrate paleontology on the Frost Museum of Science in Miami who wasn’t concerned within the research, mentioned he was floored by the invention — and that his shock was combined with a splash of “very friendly jealousy.”

“How he even found the specimen is just bonkers,” Woodruff mentioned of Tsogtbaatar. “He doesn’t just find a new one. He doesn’t just find the geologically oldest one. He finds [what] everyone who works on pachycephalosaurs has always wanted to find.”

Evans was equally impressed. “I was just stunned by the beauty and completeness of this particular fossil,” he says. “This is a specimen that we’ll be learning from for many, many years to come.”

Woodruff can be assured that this fossil will spawn new concepts about how pachycephalosaurs as soon as lived. He says normally paleontologists must work with very incomplete skeletons. “In our mind, we can see, we can imagine what the rest of it looked like,” Woodruff says. “But you didn’t have to imagine anything with a specimen like this. It was [all] there. The teeth are literally smiling at you.”