Growing up in Havre and then working a cattle ranch with her husband for 62 years, Carol Chagnon gave little thought to the idea that dinosaurs once roamed what is now her backyard.
When her sons were younger they would hike the hills and find buffalo bones — another species now gone from the area — but she never gave dinosaurs much consideration.
Now a fantastically preserved, 75 million-year-old plant-eater named Zuul — discovered over the hill from Chagnon’s house in 2014 — has gone on display in Toronto’s Royal Museum of Ontario in a special exhibit. It’s been described as the most complete skeleton of its kind ever found.
“Zuul is really special,” said David Evans in a telephone interview. He’s the museum’s paleontologist and co-curator of the exhibit “Zuul: Life of an Armoured Dinosaur."
The place where the dinosaur was found doesn't look spectacular, but the badlands hillside has turned out to be very unusual.
“It’s about the size of a football field, and over 100 feet deep,” Evans said. “It’s one of the biggest dinosaur quarries I’ve ever seen.”
“Come face to face with Zuul, the gnarly-faced, horned armoured dinosaur with a sledgehammer-like tail in this ROM original exhibition,” the museum advertises on its website.
The ankylosaurus gets its name from the 1984 “Ghostbusters” movie in which the demonic-looking beast named Zuul possesses the character played by actress Sigourney Weaver.
Identified by paleontologists as a new species, what sets the ankylosaur apart is how exquisitely it was preserved and how much of it was unearthed. From its ridged head, across its rough and tough hide covered with osteoderms — bony deposits that form scales and plates somewhat like those found on a crocodile’s back — on down to its spiked and club-like tail, Zuul’s body has been removed from the earth largely intact. Even portions of its skin were fossilized.
Ankylosaurs are rare in the fossil record, Evans explained, accounting for only about 5 percent of dinosaurs ever found. And none are as complete as Zuul, nor do they preserve the armor plates — ranging from pea size to as big as a dinner plate — in the positions they occupied when the dinosaur was alive.
“They were quite adorned,” Evans said, and the preservation is so good scientists can see growth lines in the scales.
“It gives us an amazing view of what these dinosaurs would have looked like,” he said.
Beauty of the beast
When alive, Zuul would have weighed about 2.5 tons — a bit more than a rhinoceros — and stretched to 20 feet from the tip of its nose to its weaponized tail. The tail club could have served a dual purpose: crushing the ankles and shins of threatening predators like Tyrannosaurus rex, and serving as a dueling object when fighting for mates with others of its own kind.
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Built low to the ground, flat and wide like an ancient Humvee, the dinosaur had four horns on its head, one behind and under each eye. It even had armored eyelid covers. The horns and design of its skull helped paleontologists identify it as different from similar dinosaur discoveries.
The area where Zuul was discovered is part of the Judith River Formation, a layer of sandstone that extends down from Canada to just north of Lewistown. That’s the same geologic formation that in 2000 produced Leonardo, a 77-million-year-old duckbilled dinosaur found west of Malta along the Hi-Line and so well preserved — including its skin and internal organs — that it has been called mummified.
“Although some Montana dinosaurs have skin and other originally non-biomineralized remains, as of yet, feathers and similar structures are rare,” said paleontologist Mary Schweitzer, of North Carolina State University, in an email. “But there is always hope, and the more we know about HOW these materials are preserved, the better informed we are about where to look! Montana seems to be better than some other areas at preserving eggs and nests.”
Schweitzer worked on another Judith River fossil, a plant-eating hadrosaur, which contained “still-soft blood vessels and cells deep within its bones, but also fragments of the proteins comprising them,” she wrote. “Many dinosaurs from this formation also produce skin and other soft tissues, and many are articulated as in life. We are testing many possibilities of conditions that may lead to this type of preservation.”
Finding dinosaur fossils in the Judith formation has been very difficult, but those that are found tend to be special, Evans said. Zuul was buried 30 to 40 feet into a hillside and about 40 to 50 feet deep, so it wasn’t poking up out of the earth where someone would see it. That helped preserve the fossil, since it wasn’t weathered, frozen and thawed, or broken by plant roots, Evans pointed out.
Back when Zuul ruled, large portions of Eastern Montana would have been under water, part of a shallow inland sea that cut North America in half from Canada to Mexico. Zuul was quickly buried in a flood of a small freshwater river’s backchannel along a floodplain that was crisscrossed and braided by several similar streams, Evans said.
It may have taken about four floods to completely bury Zuul, in that time a meat-eater could have dined on its legs — the only missing parts of the fossilized animal. Flipped onto its back by the water, Zuul was quickly buried in the sand, feet up, allowing for such excellent preservation of its armored back.
The quarry where Zuul was found has a spectacular assemblage of other fossils, as well. Fossilized plants are giving paleontologists a better understanding of what the environment would have been like. Pieces of freshwater mollusks, ancient ostriches, crocodiles and snail shells were preserved. What the diggers were first targeting when they stumbled upon Zuul was the fossil of a meat-eating tyrannosaurus.
“It’s an incredible window into what the world was like 75 million years ago in Montana,” Evans said.
“I’ve been working in that area 15 years and we’ve found nothing like the quality of that specimen. We haven’t even found a complete turtle shell, and there’s 10 of them with Zuul.”
Evans called the dinosaur a once-in-a-lifetime discovery, and even though he didn’t find it — a commercial company that leased the land from Chagnon unearthed Zuul — he still feels incredibly lucky to work on the project.
Once Zuul is entirely free from its rock embrace — a painstakingly slow process that is expected to be completed by the end of January — Chagnon plans to travel the 1,700 miles to Toronto, Canada, and see the creature that once lay trapped in sandstone so close to her badlands ranch along the Milk River.
“It’s going to be quite impressive,” she said.