The dinosaur was given a rather unfair name, as it was almost certainly a peaceful vegetarian.

I’d say the newly-discovered dinosaur looks quite peaceful, as far as dinosaurs go. Image credits: Danielle Dufault / Royal Ontario Museum

The team of paleontologists from the Royal Ontario Museum and the University of Toronto, Canada, were actually digging out a different fossil when they came across the tail of this new dinosaur. They quickly expanded the excavation, uncovering an ankylosaurus which measured approximately 20 feet long, and likely weighed approximately 5,500 pounds, making it roughly the size of a modern white rhinoceros. Researchers dated the dinosaur to some 75 million years ago — not long before the mass extinction that wiped out the dinosaurs.

The species was quickly identified as an ankylosaur, a genus of armored dinosaur which survived right up until the end of the Mesozoic. It was one of the last non-avian dinosaurs to walk the face of the Earth, wobbling around with its nigh-impenetrable scales and club-like tail. But while its tail was definitely extremely good at striking down enemies, it wasn’t used at striking prey, because ankylosaurs were vegetarian. In fact, we know that they preferred “non-selective low-browse cropping” — which means they just grazed on pretty much everything low enough. I say low enough because despite their imposing stature,  their jaw movement was likely limited to simple, up and down movements. Like modern herbivorous lizards, they digested their food through a hindgut fermentation system and employed some kind of chewing.

In terms of these general characteristics, the new species checks all the boxes, but in terms of facial aspect, it looks a bit different.

“I half-jokingly said it looks like Zuul [from Ghostbusters],” said the lead author on this study, Victoria Arbour, a PhD fellow at the ROM and University of Toronto, and an all-around expert on armoured dinosaurs. “The name just stuck.”

“Zuul would be easy to recognize based on the shape of the horns at the back of the skull and by the rough, peaked ornamentation along the snout and in between the eyes on the forehead.”

Skull of Zuul crurivastator. Credit: Brian Boyle / Royal Ontario Museum.

Zuul is one of the most emblematic bad guys you’ll see in movies, it inspired its own subreddits, memes, and once, a heavy metal band. If you haven’t seen the old Ghostbusters movies, you’ve missed out — seriously. But there’s more to this dinosaur than a cute reference, and again — I’ll get back to the tail.
The species was officially named Zuul crurivastator — the second part of its name in rough translation means “destroyer of shins,” a clear reference to its 6.7 foot, 13-vertebra-spiked tail, which also featured a knob or hammer-like end. The tail basically had a club at the end, and the vertebra near the end of the tail had a thin V-shape which acts as a mobile handle for the club. It was a formidable weapon, which ankylosaurs undoubtedly used every handily.
“I’ve been itching to name an ankylosaur ‘ankle breaker’ for years, but was waiting for a specimen that included a nice tail club,” Arbour says, “and they don’t get much nicer than this.”
Most notably, this is one of the most complete dinosaur skeletons ever found, and the most complete dinosaur of its type discovered in North America, offering an important puzzle piece regarding the evolution of the dinosaur community. The fossil is so well-preserved than it even preserves the armor plate.
“Because the armor plates are in the skin, they often fall away from the skeleton after death as the animal is decomposing,” Arbor comments, offering an interesting glimpse onto how the dinosaur really looked like.
Journal Reference: Victoria M. Arbour, David C. Evans — A new ankylosaurine dinosaur from the Judith River Formation of Montana, USA, based on an exceptional skeleton with soft tissue preservation. DOI: 10.1098/rsos.161086.

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