World’s Best-Preserved Armored Dinosaur, a ‘Mona Lisa’ of Fossils, Found in Alberta

Borealopelta-dinosaur

The fossil of an armored dinosaur bristling with spikes and scales found in Alberta is so complete and well-preserved that it resembles a statue, scientists say.

But the specimen is far more than a gorgeous spectacle.

Its remarkable state of preservation has allowed researchers to determine that the animal is a new species to science, and its prickly skin even contains molecular clues to its coloration, revealing insights into just how competitive the Ancient West was more than 100 million years ago.

The newly found species was the “dinosaur equivalent of a tank,” as the researchers put it, at 5.5 meters long (about 18 feet) and weighing more than 1,300 kilograms (or 2,800 pounds) — but what’s most striking about it is its excellent condition.

“This [dinosaur] is truly remarkable in that it is completely covered in preserved scaly skin, yet is also preserved in three dimensions, retaining the original shape of the animal,” said Dr. Caleb Brown, paleontologist at the Royal Tyrrell Museum, in a press statement..

“The result is that the animal looks almost the same today as it did back in the Early Cretaceous.”

The fossil was unearthed by heavy machinery at an oil sands mine in eastern Alberta in 2011.

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Two views show the type specimen for the dinosaur Borealopelta markmitchelli. (Courtesy of the Royal Tyrrell Museum of Palaeontology, Drumheller, Canada. May not be used without permission.)

The rock layer where it was found dates back 110 million years — unexpected, considering that the site at the time was deep under the Western Interior Seaway, the inland sea that once separated the westernmost part of the continent from the east.

Paleontologists called to the scene speculated that the dinosaur must have died near the shore and then was swept out to sea, where a series of very fortunate taphonomic events caused it to be preserved in such excellent condition.

After its body sank to the seafloor, currents apparently swept a large amount of sand into the animal’s body cavity, which later hardened into sandstone, helping to preserve the shape of the dinosaur in all three dimensions.

“Finding the remains of an armored dinosaur that was washed far out to sea was huge surprise,” said Dr. Donald Henderson, curator of dinosaurs at the Royal Tyrell Museum, in the same statement.

“The fact that it was so well preserved was an even bigger surprise.”

It took five and a half years for preparators to carefully remove the surrounding siderite rock from around the fossil, but the results revealed an almost entirely intact kind of dinosaur known as a nodosaurid, preserved from its snout to its hips.

Nodosaurids are a type of ankylosaur, the four-legged, herbivorous armored dinosaur that includes the famous Ankylosaurus and more recent finds, like Ziapelta, recently unearthed in New Mexico.

(Read about Ziapelta’s discovery: “Spiky, Scaly New Species of Ankylosaur Discovered in New Mexico“)

And researchers say this new specimen is the best preserved nodosaurid ever found — indeed, one of the best preserved dinosaurs ever.

“You don’t need to use much imagination to reconstruct it,” Brown said.

“If you just squint your eyes a bit, you could almost believe it was sleeping…

“It will go down in science history as one of the most beautiful and best preserved dinosaur specimens — the Mona Lisa of dinosaurs.”

Such fulsome praise would be hard for any animal to live up to, but this specimen has already provided a wealth of knowledge, as well as some wows, researchers say.

For one thing, judging by a variety of unique features — like the ornamentation around its eyes, six-sides plates on the sides of its skull, and distinct alternating lines of spikes and scales along its back — this nodosaurid belongs to a genus that’s new to science.

It’s been named Borealopelta, or “northern shield.”

The specimen also includes a host of fossilized tissues, including the bony knobs on its back and shoulders, known as osteoderms, as well as the sheaths of keratin that covered them, and the scales of its skin.

And these scales have turned out to hold troves of molecular information about how Borealopelta looked in life, and why it looked that way.

Using a technology called ion mass spectrometry, the researchers were able to detect compounds in the keratin sheaths and scales that they think are variations of melanin, the pigment that creates coloration in many animals, including humans.

The chemical signature in some swaths of melanin was consistent with a red-colored compound known as pheomelanin.

Other parts of the animal’s flanks and neck, meanwhile, revealed little or no melanin, suggesting that these regions were “dramatically lighter” than the back.

Borealopelta-picture
An illustration of the 110-million-year-old Borealopelta markmitchelli demonstrates its countershading, with dark reddish coloration on top and lighter coloration on the bottom. (Courtesy of the Royal Tyrrell Museum of Palaeontology, Drumheller, Canada. May not be used without permission.)

Thus, the researchers conclude, Borealopelta likely benefited from a pattern of camouflage known as countershading, in which an animal is lighter on the underside and darker on its back.

Countershading is common in many modern animals, from penguins to squirrels.

But the fact that an armored dinosaur the size of a small car used such a strategy suggests that predation was so great in the Cretaceous even these ancient tank-like dinos needed some cover.

“Strong predation on a massive, heavily-armored dinosaur illustrates just how dangerous the dinosaur predators of the Cretaceous must have been,” Brown said.

But this is only the first wave of research to come from this statuesque specimen.

(Read about an even more recent, related find: “America’s Most Complete Armored Dinosaur, Soft Tissues Intact, Found in Montana“)

The tar-sands ankylosaur now known as Borealopelta is sure to reveal voluminous new insights into the group of four-legged, armored dinosaurs known as the thyreophorans, the researchers say.

“The discovery of a three-dimensionally preserved ankylosaurian provides new evidence for understanding the anatomy, soft tissue outline, and arrangement of dermal armor in thyreophoran dinosaurs,” the team writes in their paper reporting the find.

They published their findings in the journal Current Biology.

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