(Photo: Juliis Csotonyi, Bell, Fanti, Currie, Arbour)
The duck-billed dinosaur known as Edmontosaurus regalis was supposed to be a plain Jane of the Cretaceous. No elaborate neck frill for it, nor horns, nor spikes, nor any of the fancy headgear sported by many of its cousins.
Now scientists have discovered that Edmontosaurus regalis actually had a spectacular adornment unique in the dinosaur world. A beautifully preserved new fossil shows Edmontosaurus boasted a party hat of jiggly flesh atop its head. Researchers theorize that like a rooster's coxcomb, the crest was brightly colored and served as a signal to others of its kind. Never before have scientists found such a non-bony crest on a dinosaur.
"We saw something we simply didn't expect to find - a soft-tissue crest on top of its head," said paleontologist Federico Fanti of the University of Bologna, an author of the new study. "This is changing the way we imagine and even understand dinosaurs."
When Fanti found the 73 million-year-old fossil along a river in Alberta, Canada, in 2011, no one judged it anything special. All that could be seen were some vertebrae sticking out of a coffin-sized sandstone block, and the researchers left the block sitting in the field for weeks before trucking it back to the lab.
As tools liberated the fossil from its stone wrapper, the scientists slowly realized that they had a spectacular find on their hands. What emerged from the rock was an extremely rare dinosaur "mummy," a specimen including not just fossilized bone but also soft tissues such as skin. The greatest surprise came as paleontologist Phil Bell of the University of New England in Australia chipped along the fossil's head and found flesh where there shouldn't have been any.
His first thought, Bell says, was that "it must be some kind of mistake. But every way I looked at it, I could only come up with one answer, and that answer was, this animal had a crest."
The curved crest reached 8 inches high and roughly a foot in length, making it look like a too-small bowler hat for an animal that weighed as much as a small bulldozer and stretched more than 30 feet long. Roosters and condors have brightly colored crests, so Edmontosaurus could have, too.
Some dinosaurs with crests made of bone probably used their headgear for sound production. Edmontosaurus apparently didn't. It was a company-loving creature that lived at least part of the year in large herds, and the crest probably served as a signal to its buddies, relatives or potential love interests.
Scientists not associated with the study, published in this week's Current Biology, said it was persuasive in showing that the fossil had a crest, a find credited in part to Bell's deftness with a chisel.
"Cutting diamonds is easy compared to what these guys have done with this fossil," says the University of Manchester's Phillip Manning, who has also worked on a dinosaur mummy. "The fellows who undertook this prep work were absolute artists." Manning agrees with the authors that the crest very well could've been used as a signal to others in the herd. Many dinosaurs had hidden genitals, so maybe the crest was a clue to gender, he says.
Eye-catching features "are used (widely) in the animal kingdom today," Mannig says. "Why should dinosaurs be any different?"
The discovery shows there's always more to learn, even about animals as common and well-studied as Edmontosaurus.
"Edmontosaurus has been known for, oh, 120 years," says Johns Hopkins University School of Medicine's David Weishampel, co-editor of a scholarly compendium of dinosaurs. "And we had not an inkling that at least some of them, if not all of them, had ... a small but significant-sized crest. It all holds together."