Thanks to an ancient mummy, scientists now know that the duck-billed dinosaur Edmontosaurus regalis sported a snazzy ornament atop its head akin to a rooster’s red crest. This fleshy comb is the first soft-tissue display structure ever discovered in a dinosaur.
The exact function of the dinosaur’s pliable crest is uncertain. But in their paper describing the new remains, published today in Current Biology, Phil R. Bell of the University of Armidale in Australia and his colleagues note that the structure would have been impractical for defense or combat, and was not large enough to serve as an energy reserve for the animal, which would have tipped the scales at around eight tons as an adult. The authors further observe that in modern birds such crests are secondary sexual structures, with the size and color of the comb advertising the health and fertility of an individual to potential mates and rivals. Given the similarity between the mummified crest and the crests of living birds, as well as the close evolutionary relationship between duck-billed dinosaurs and birds, the Edmontosaurus comb probably played a major role in sexual signaling, the team concludes.
Some experts had previously speculated that duck-billed dinosaurs possessed soft-tissue crests, but they lacked direct evidence for the structures—until now. Intriguingly, the researchers did not find any features on the skull itself that would attest to the presence of a soft-tissue crest. So, in theory, other dinosaurs species could have had the fleshy head ornaments, too--paleontologists just would not be able to tell from their bones alone.
The mummified remains were found in deposits in west-central Alberta, Canada, and dated to more than 72 million years ago.