February 29, 2024

Complex Behavior of Armored Dinosaurs: Ankylosaurs Battled Each Other As Much as They Fought Off T. rex

Zuul crurivastator in fight. Credit: Illustrated by Henry Sharpe © Henry Sharpe.
Zuul shows that ankylosaurs may have likewise used their tail clubs for social supremacy.
Researchers have found brand-new proof for how armored dinosaurs used their renowned tail clubs. The extraordinary fossil of the ankylosaur Zuul crurivastator has spikes along its flanks that were broken and re-healed while the dinosaur was alive– injuries that the researchers believe were brought on by a strike by another Zuuls huge tail club. This recommends ankylosaurs had complicated behavior, possibly fighting for social and territorial supremacy or even engaging in a “rutting” season for mates.
The research study, by researchers from the Royal Ontario Museum (ROM), Royal BC Museum, and North Carolina Museum of Natural Sciences, was published on December 7 in the journal Biology Letters.

The extraordinary fossil of the ankylosaur Zuul crurivastator has spikes along its flanks that were broken and re-healed while the dinosaur was alive– injuries that the scientists think were caused by a strike by another Zuuls huge tail club. The 76-million-year-old, plant-eating dinosaur, part of the Royal Ontario Museums vertebrate fossil collection, is called after the imaginary monster Zuul from the 1984 movie Ghostbusters. Zuuls tail is about three meters (10 feet) long with sharp spikes running along its sides. Zuul crurivastator implies Zuul, the destroyer of shins, a nod to the idea that tail clubs were utilized to smash the legs of bipedal tyrannosaurs. The completely protected back and tail of Zuul, consisting of skin, allowed for an uncommon glimpse into the lives of these unbelievable armored dinosaurs.

Zuul crurivastator skull. Credit: © Royal Ontario Museum
The 76-million-year-old, plant-eating dinosaur, part of the Royal Ontario Museums vertebrate fossil collection, is called after the fictional monster Zuul from the 1984 movie Ghostbusters. The skull and tail had actually been released from the surrounding rock, however the body was still framed in 35,000 pounds of sandstone. After years of work, the body was exposed to have maintained most of the skin and bony armor throughout the entire back and flanks, offering an amazing view of what the dinosaur looked like in life.
Zuuls body was covered in bony plates of various sizes and shapes and the ones along its sides were spiky and particularly large. Remarkably, the scientists noticed that a number of spikes near the hips on both sides of the body are missing their tips and the bone and horny sheath has actually healed into a blunter shape. The pattern of these injuries is more constant with being the result of some form of ritualized fight or jousting with their tail clubs, and probably werent brought on by an assaulting predator like a tyrannosaur due to the fact that of where they are located on the body.
Zuul crurivastator image and illustration with injured spikes marked in red. Credit: Danielle Dufault, © Royal Ontario Museum
” Ive had an interest in how ankylosaurs utilized their tail clubs for many years and this is a really amazing brand-new piece of the puzzle,” says lead author Dr. Victoria Arbour, Curator of Palaeontology at the Royal BC Museum and former NSERC postdoctoral fellow at the Royal Ontario Museum. “We know that ankylosaurs could use their tail clubs to deliver really strong blows to a challenger, but many people believed they were using their tail clubs to eliminate predators. Rather, ankylosaurs like Zuul might have been fighting each other.”
Hurt and recovered spike from Zuuls left side. Credit: © Royal Ontario Museum
Zuuls tail is about 3 meters (10 feet) long with sharp spikes running along its sides. Zuul crurivastator indicates Zuul, the destroyer of shins, a nod to the concept that tail clubs were used to smash the legs of bipedal tyrannosaurs.
Hurt and recovered spike on Zuuls best side. Credit: © Royal Ontario Museum
Years earlier, Arbour had actually put forward the concept that ankylosaurs might have clubbed each other in the flanks, which broken and healed ribs may supply proof to support this concept. Ankylosaur skeletons are very rare, making it tough to test this hypothesis. The completely preserved back and tail of Zuul, consisting of skin, enabled an unusual glimpse into the lives of these amazing armored dinosaurs.
” The truth that the skin and armor are preserved in place is like a picture of how Zuul looked when it lived. And the injuries Zuul sustained during its life time tell us about how it might have behaved and connected with other animals in its ancient environment,” said Dr. David Evans, Temerty Chair and Curator of Vertebrate Palaeontology at the Royal Ontario Museum
Intact flank spike from Zuul. Credit: © Royal Ontario Museum.
The remarkable skeleton of Zuul was discovered in the Judith River Formation of northern Montana and gotten by the ROM through the generous support of the Louise Hawley Stone Charitable Trust.
Reference: “Palaeopathological evidence for intraspecific fight in ankylosaurid dinosaurs” by Victoria M. Arbour, Lindsay E. Zanno and David C. Evans, 7 December 2022, Biology Letters.DOI: 10.1098/ rsbl.2022.0404.
Funding for this project was likewise provided by the Natural Sciences and Engineering Research Council, LOreal-UNESCO for Women in Science, Alberta Innovates, and the Dinosaur Research Institute.