The canine-sized dinosaur initially led scientists to believe it belonged to a different family. In addition, it sports an unusual tail weapon not found on any other mammal.

According to research released on Wednesday, fossils discovered in Chile are from a strange-looking, dog-sized dinosaur species that had a special slashing tail weapon.

For stabbing purposes, some dinosaurs possessed tails with spikes, while others had tails with clubs. According to senior author Alex Vargas, the new species, which was reported in a research published in the journal Nature, features seven pairs of “blades” arranged sideways like a slicing weapon used by ancient Aztec warriors.

“It’s a really unusual weapon,” said Vargas, a University of Chile paleontologist. “Books on prehistoric animals for kids need to update and put this weird tail in there. … It just looks crazy.”

The plant-eating critter had a combination of traits from different species that initially sent paleontologists down the wrong path. The back end, including its tail weapon, seemed similar to a stegosaurus, so the researchers named it stegouros elengassen.

After Vargas and his team examined the pieces of skull and did five different DNA analyses, they concluded it was only distantly related to the stegosaurus. Instead, it was a rare southern hemisphere member of the tank-like ankylosaur family of dinosaurs. (Though the stegouros name stuck and can be easily confused with the more well-known stegosaurus.)

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

The fossil is from about 72 million to 75 million years ago and appears to be an adult based on the way bones are fused, Vargas said. It was found with its front end flat on its belly and the back end angled down to a lower level, almost as if caught in quicksand, Vargas said.

Credit: APThis illustration provided by Mauricio Alvarez shows a Stegouros. Fossils found in Chile are from the bizarre dog-sized dinosaur species that had a unique slashing tail weapon, scientists reported Wednesday, Dec. 1, 2021. (Mauricio Alvarez via AP)

From bird-like snout to tail tip, stegouros stretched about six feet but would only come up to the thighs of humans, Vargas said.

The tail was probably for defense against large predators, which were also likely turned off by armor-like bones jutting out that made stegouros “chewy,” Vargas said.Credit: APThis illustration provided by Luis Perez Lopez shows a Stegouros. Fossils found in Chile are from the bizarre dog-sized dinosaur species that had a unique slashing tail weapon, scientists reported Wednesday, Dec. 1, 2021. (Luis Perez Lopez via AP)

Not only is this “a really bizarre tail,” but it is from far southern Chile, “a region that hasn’t yielded these types of animals before,” said Macalester College biologist Kristi Curry Rogers, who wasn’t 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 times, there is so much more still to discover.”

Source: king5.com