Smithsonian.com

The skeleton of Edmontosaurus on display at the Smithsonian National Museum of Natural History.

In the winter of 2007, news agencies were all a-twitter over the news of another “mummy” hadrosaur found in North Dakota. Nicknamed “Dakota”, the dinosaur was said to “exceed the jackpot” of what paleontologists could have hoped for, and two books, a documentary and a lecture tour were arranged to promote the fossil. All the while, however, scientists have been waiting for a scientific description of Dakota to be published. After a long wait, the first detailed study of Dakota finally appeared in the Proceedings of the Royal Society B this past week.

Dinosaur mummies, or dinosaurs with skin impressions intact, have been known for over a century. What might make Dakota special, however, is that the fossil preserves much more than just the impressions of the skin. As recent research by paleobiologists like Mary Schweitzer has shown, sometimes degraded remnants of original dinosaur organic material can survive the fossilization process under the right conditions. The authors of the description of Dakota suggest that their specimen, too, contains some detailed traces of the dinosaur’s original body.

Even though the body of “Dakota” has yet to be fully uncovered, and the paleontologists are still unsure as to what species of Edmontosaurus the dinosaur is, enough of the fossil has been studied to reveal the exceptional detail of the dinosaur’s preservation. Indeed, it appears that the fossil preserves about two inches of skin, not just impressions of the top layer, and in the skin layer are what appear to be cell-like structures. There even seemed to be remnants of the tough sheath that would have covered some of the toe bones (“dinosaur toenail”), and tests suggested that it, too, was preserved material from the original dinosaur’s body.

These findings are not quite as dramatic as the studies of preserved Tyrannosaurus and Brachylophosaurus soft-tissue structures carried out by Mary Schweitzer and her colleagues, but it does suggest that we should look more closely at some other known “dinosaur mummies.” Perhaps they too preserve some cells or other minute details that have been ignored. Paleontologists will continue to search for and study bones, but a whole new branch of paleontology is opening up inside the microbiology lab.