Bones, which are particularly suitable for forming fossils because they are hard and durable, give scientists a good amount of of information about the animal they came from, such as its size, how it moved, and even what it ate. But sometimes bones are silent on other important points, like an organism’s outermost appearance, or how it chose a mate.
If you were to study the skeleton of a rooster, for example, (and no one had ever seen a rooster before) you would know that roosters were bipedal, that they had wings but didn’t fly well, and if its beak was preserved, you would even be able to guess at its omnivorous diet. However, you wouldn’t necessarily be able to tell that it had feathers. If you guessed that it had feathers, you probably wouldn’t ever know about the beautiful plumes of its tail, and it would be almost impossible to guess that it had a fleshy red crest that fell over the top of its beak.
Softer and more delicate (or edible) animal structures do not fossilize as easily as bone. This is why it took a magnificent stroke of luck for a team of paleontologist studying a hadrosaur fossil from Alberta, Canada, to discover that some dinosaurs had something quite similar to rooster combs.
Hadrosaurs, also known as duck-billed dinosaurs, were large, herbivorous dinosaurs that grazed in herds around the plentiful fresh water sources of the Cretaceous. Hadrosaurs are some of the most common, well-known, and well-studied types of dinosaurs known to paleontologists – and that is why Phil Bell from the University of New England in Armidale, Australia, was not expecting to find anything too surprising while chiseling out the skeleton of the hadrosaur Edmontosaurus regalis skeleton.
“I was just expecting there to be rock, and all of a sudden there was skin underneath, and I thought to myself, ‘Whoops,'” said Philip Bell, whose findings are reported in Current Biology, December 2013. Under his chisel, he found the mummified impression of a soft fleshy structure on top of the dinosaur’s head. The structure was much like the comb of a rooster, and would have looked a little like a fez. “There’s never been any indication that any dinosaurs had something like this, so this was totally out of left field,” said Bell.
Certain species of hadrosaur were known to have elaborate bone structures on top of their heads. Some, like that of the Parasaurolophus, were hollow and are thought to have been used to trumpet to other herd members. But all of the known structures were made out of bone.
Scientists never imagined that Edmontosaurus regalis might have looked so flashy. “With its extensive fossil record,” said Curator of Vertebrate Paleontology at the Royal Ontario Museum in Toronto, Canada, David Evans, “Edmontosaurus is generally thought to be one of the very best known dinosaurs, but this specimen underscores how new discoveries can drastically change the way we think about these animals. Edmontosaurus will never be that plain, unornamented duck-billed dinosaur ever again.”
Horner, J. R. (2014). Paleontology: A Cock’s Comb on a Duck-Billed Dinosaur. Current Biology, 24(2), R85-R86.
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