MADRID, 7 Dic. (EUROPA PRESS) –
Scientists have found new evidence of how ankylosaurs used their iconic tail clubs, proving that they fought both among themselves and with their predator, the T.Rex.
The rare fossil of the ankylosaur Zuul crurivastator has spikes along its flanks that broke off and healed once more while the dinosaur was alive, injuries scientists believe may have they were caused by a blow with the huge club from the tail of another Zuul.
This suggests that ankylosaurs had complex behavior, possibly fighting for social and territorial dominance or even participating in a season of “rut” to mate. The research is published in the journal Biology Letters.
The 76-million-year-old herbivorous dinosaurpart of the Royal Ontario Museum’s Vertebrate Fossils Collection, It is named following the fictional “Zuul” monster from the 1984 “Ghostbusters” film. Initially, the skull and tail had been freed from the surrounding rock, but the body was still encased in tons of sandstone. After years of work, the body was revealed to have retained most of the skin and bone armor on its entire back and flanksgiving a remarkable view of what the dinosaur looked like in life.
Zuul’s body was covered in bony plates of different shapes and sizes, and the ones on the sides were particularly large and pointy. Interestingly, the scientists noted that several spikes near the hips on both sides of the body were missing their tips, and the bone and horny sheath had healed into a more blunt shape. The pattern of these injuries was more consistent with the result of some sort of ritualized combat, or jousting with her tail clubs, and was probably not caused by an attacking predator such as a Tyrannosaurus due to the location on the body.
“I’ve been interested in how ankylosaurs used their tail clubs for years and this is a really exciting new piece of the puzzle,” says lead author Dr. Victoria Arbor, Curator of Paleontology at the Royal Museum of British Columbia and former postdoctoral fellow at the Royal Ontario Museum.
“We know that ankylosaurs might use their tail clubs to deliver very heavy blows to an opponent, but most people thought they were using their tail clubs to fight off predators.. Instead, ankylosaurs like Zuul may have been fighting each other.”
Zuul’s tail was regarding ten feet long, with sharp spikes along its sides. The rear half of the tail was stiff and the tip was encased in huge bony knobs, which created a formidable mace-like weapon.
Zuul crurivastator means “Zuul the shin destroyer”, a nod to the idea that the tail clubs were used to crush the legs of bipedal tyrannosaurs. The new research doesn’t refute the idea that tail clubs might be used in self-defense once morest predators, but it does show that tail clubs would have worked for interspecies combat as well, a factor that likely drove their evolution. Today, specialized animal weapons, such as deer antlers or antelope horns, have evolved to be used primarily to fight members of the same species during tag or territory battles.
Years ago, Arbor had put forward the idea that ankylosaurs might have struck each other on the flanks, and that healed and broken ribs might provide evidence to support this idea. But ankylosaur skeletons are extremely rare, making it difficult to test this hypothesis. Zuul’s fully preserved back and tail, including skin, they allowed an unusual glimpse into the lives of these incredible armored dinosaurs.
“The fact that the skin and armor are kept in place is like a snapshot of what Zuul looked like when he was alive. And the injuries Zuul sustained during his life tell us how he may have behaved and interacted with other animals in his ancient environment,” said Dr. David Evans, Temerty Chairman and Curator of Vertebrate Palaeontology at the Royal Ontario Museum.
The remarkable Zuul skeleton was found in the Judith River Formation in northern Montana.