The new species of dinosaurs in Chile had a unique sharp tail

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Some dinosaurs had pointed tails that they could use as stabbing weapons, and others had sticks with tails. The new species, described in a study in the journal Nature, has so far been unseen in any animal: seven pairs of “blades” placed sideways, like a cutting weapon used by ancient Aztec warriors, said lead author Alex Vargas.

“It’s a really unusual weapon,” said Vargas, a paleontologist at the University of Chile. “Children’s prehistoric animal books need to be updated and put that weird queue in there. … It just sounds crazy. ”

The plant-eating creature had a combination of traits from different species that initially sent paleontologists astray. The back end, including the tail weapon, looked similar to a stegosaurus, so researchers called it stegouros elengassen.

After Vargas and his team examined the pieces of the skull and performed five different DNA tests, they concluded that it was only a distant relative of the stegosaurus. Instead, it was a rare member of the southern hemisphere in the reservoir-like ankylosaur dinosaur family. (Although the name stegouros has remained and can be easily confused with the better known stegosaurus.)

Vargas called it the “lost branch of the ankylosaur family.”

The fossil is now about 72 million to 75 million years old and appears to be an adult, based on the way bones are fused, Vargas said. He was found with his front end flat on his stomach and his back end tilted to a lower level, almost trapped in quicksand, Vargas said.

From the snout like a bird to the tip of its tail, the flagpole stretched about two meters, but only reached people’s thighs, Vargas said.

The tail was probably for defense against large predators, which were also probably stopped by protruding armor-like bones, which made stegouros “chewed,” Vargas said.

Not only is this a “really weird queue,” but it’s from the far south of Chile, “a region that has never seen such animals before,” said Macalester College biologist Kristi Curry Rogers, who did not part of the study. .

“We’re just scratching the surface when it comes to a comprehensive understanding of dinosaur diversity,” Rogers said. “Stegourus reminds us that if we look in the right places at the right time, there is much more to discover.”