Uncommon fossil reveals ‘destroyer of shins’ dinosaurs fought one another

Injury to the spikes on the edges of a fossil of a Zuul crurivastator recommend that these armoured dinosaurs didn’t solely use their tail golf equipment to fend off Tyrannosaurs but additionally to battle one another

By Sam Jones

Zuul, destroyer of shins, was a residing tank. This dinosaur’s backbone and tail had been lined in armoured plates studded with spikes, ending in a membership beforehand thought for use to battle off vicious predators just like the Tyrannosaurus rex. However a uncommon fleshy fossil suggests these armoured herbivores in all probability used their tails much less to fend off T. rex and extra to dominate one another.

Zuul crurivastator’s identify comes from the demonic Zuul from the 1984 movie Ghostbusters, with crurivastator which means “destroyer of shins”. Its fossil was found almost a decade in the past – throughout a dig in Montana to unearth a Gorgosaurus, an earlier cousin of T. rex – when excavators ran into the dinosaur’s tail membership. Years later, when researchers on the Royal Ontario Museum in Toronto had been getting ready the fossil for exhibition, they discovered that among the fossil’s spikes had been broken. Many of those had clean areas indicating the bone had reformed, and a few had growths of keratin – each indicators of therapeutic, suggesting accidents on a number of events.

“The [damaged spikes] are just in this little range around the hips, and just on the sides of the body,” says Victoria Arbour on the Royal BC Museum in British Columbia. They’re not damaged on the highest of the physique or up by the pinnacle, which is the place you’d count on a predator like T. rex to assault, she says.

“Big, predatory dinosaurs can bite with enough force to leave scratches and puncture marks on bone,” says Arbour. However these marks are lacking on this fossil.

Based mostly on the broken spikes being at totally different phases of therapeutic, and in a location each simply reachable by one other Z. crurivastator’s swinging tail and unlikely to be deadly, the researchers imagine the dinosaurs used their tails to battle one another for social dominance. They believe it was just like the best way fashionable animals use antlers or different physique elements to stake declare to territory or mates. So, though the club-like tail might have come in useful for self-defence, its evolution was in all probability pushed extra by sexual choice than predation.

The concept of those dinosaurs utilizing their tail golf equipment to battle off T. rex had “become something of a textbook stereotype”, says Stephan Lautenschlager on the College of Birmingham within the UK. He sees this examine as a chief instance of how a long-standing speculation may be upended with new proof. “Now that palaeontologists know what to look for, the same damage in other, maybe yet-undiscovered, fossils could come to light,” he says.

Journal reference: Biology Letters, DOI: 10.1098/rsbl.2022.0404