Ankylosaurs used their mass tails to fight | CNN

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Armored dinosaurs called ankylosaurs may have wielded hammer-like tail clubs at each other in conflict, in addition to fending off predators like Tyrannosaurus rex.

A well-preserved fossil of an ankylosaurus, a herbivorous dinosaur that lived 76 million years ago, is changing the way scientists understand armored dinosaurs and how they used their clubs.

A study of the fossil revealed spikes on the dinosaur’s flanks that were broken off and healed while the animal was still alive. Researchers believe the injuries were caused when another ankylosaur struck the dinosaur with its tail club.

The study published Tuesday in the journal Biology Letters.

Ankylosaurus sported bony plates of varying sizes and shapes all over its body; along the sides of its body, these plates acted like large spikes. Scientists also believe that ankylosaurs could have used their weapon-like tails to assert social dominance, establish territory, or even fight for mates.

An ankylosaurus using its tail in combat against each other is similar to how animals like deer and antelope use their antlers and horns to fight each other today.

The fossil is that of a member of a particular species of ankylosaur otherwise known by its classification name, Zuul crurivastator. If the name sounds familiar, that’s because researchers borrowed Zuul’s name from a monster in the 1984 movie “Ghostbusters.”

The dinosaur’s full name means “Zuul, the Shin Destroyer”, since the ankylosaur’s tail club would have been the enemy of tyrannosaurs and other predators that walked upright on their hind legs.

These tails were up to 10 feet (3 meters) long, with rows of sharp spikes along the sides. The tip of the tail was fortified with bony structures, creating a club that could swing with the force of a hammer.

The skull and tail were the first pieces of the fossil to emerge in 2017 from a dig site in the Judith River Formation in northern Montana, and paleontologists worked for years to free the remains of the fossil from 35,000 pounds of sandstone. The fossil was so well preserved that remnants of skin and bone armor remain on the back and sides of the dinosaur, giving it a very realistic appearance.

This particular ankylosaurus looked quite battered at the end of its life, with spikes near its hips and spikes missing from the sides. After sustaining these injuries, the bone healed into a much duller shape.

Due to the location on the body, researchers do not believe the wounds were caused by a predator attack. Instead, the pattern resembles the result of a powerful snap of another ankylosaur’s tail club.

“I’ve been interested in how ankylosaurs use their tail clubs for years and this is a really exciting new piece of the puzzle,” said study lead author and curator Dr Victoria Arbour. paleontology at the Royal British Columbia Museum in Victoria, Canada. , in a report.

“We know that ankylosaurs could use their clubs to deliver very powerful blows to an opponent, but most people thought they used their clubs to fight off predators. Instead, ankylosaurs like Zuul may have be beaten.

Arbor suggested the hypothesis that ankylosaurs might have adopted their behavior years ago, but fossil evidence of injuries was needed – and ankylosaur fossils are rare.

The exceptional crurivastator fossil from Zuul has helped fill this knowledge gap.

“The fact that the skin and armor are kept in place is like a snapshot of how Zuul looked when he was alive. behave and interact with other animals in their former environment,” said study co-author Dr. David Evans, Temerty Chair and Curator of Vertebrate Paleontology at the Royal Ontario Museum at Toronto, in a report.

The Zuul fossil is currently housed in the Royal Ontario Museum’s Vertebrate Fossil Collection.