"Dinosaur Mummy" Has Skin Like Birds' and Crocodiles'

Friday, August 6, 2010

The skin of a 66-million-year-old duckbilled dinosaur pokes out of the soil at the Hell Creek formation in North Dakota in 2007. Advanced imaging and chemical techniques later revealed that the dinosaur had skin like that of birds or crocodiles, a July 2009 study says. [Photograph by Tyler Lyson, copyright NGS]

There's no evidence of goosebumps just yet, but a remarkably preserved dinosaur reveals that the prehistoric reptile had skin like that of birds and crocodiles, a new study says.

"This is the closest you're going to get to patting the animal," said excavation leader Phillip Manning, a paleontologist at Britain's University of Manchester.

Advanced imaging and chemical techniques revealed that the 66-million-year-old "mummified" duckbilled dinosaur had two layers of skin, as do modern vertebrates, including humans.

Such a discovery was possible because the dinosaur's skin fossilized before bacteria had a chance to eat up the tissue.

It is "absolutely amazing to be able to identify organic molecules from soft tissue that belonged to a beast that died over 66 million years ago," said Manning, whose work with the fossil was partially funded by the National Geographic Expeditions Council. (The National Geographic Society owns National Geographic News.)

"It's certainly in my top ten all-time fossils."

World-Class Dino

Tyler Lyson, a teenager at the time, discovered Dakota, as the fossil was later dubbed, in 1999 on his family's North Dakota property. (See photos of the "mummified" dinosaur.)

No one knows how the hippo-size animal died.

But scientists do know that the body was probably buried rapidly. The resulting low-oxygen environment and the apparent lack of disturbance to the site made Dakota a "world-class dinosaur" fossil, according to the new study, published July 1 in the journal Proceedings of the Royal Society B.

Building Blocks

With electron microscopes and x-rays, Manning discovered that Dakota had cell-like structures indicative of two-ply skin: a thin surface layer plus an underlying layer of dense connective tissues.

That's just like skin of modern birds and reptiles, which scientists believe are closely related to duckbilled dinosaurs.

Protein-recovery techniques used on the skin and a claw detected amino acids, the building blocks of proteins. Proteins themselves, complex molecules that degrade easily over time, were not found, however.

(Related: "Oldest Dinosaur Protein Found—Blood Vessels, More.")

But Manning did identify molecules that would have broken down proteins in Dakota's body.

That's like finding fragments of a broken vase instead of the intact vase, explained Thomas R. Holtz Jr., a vertebrate paleontologist at the University of Maryland.

"What's really nice" about the new research is this protein-recovery strategy. It's the first time the skin of such a big plant-eating dinosaur has been analyzed so deeply, said Holtz, who was not involved in the research.

That Dakota's skin resembles modern vertebrate skin is not surprising but nonetheless "comforting," Holtz added.

Beyond Bones

Understanding the exact environments that froze Dakota in time may help paleontologists better target future fossil hunts, lead study author Manning said.

"Who knows? The elusive dinosaur mummies of the fossil record might be more common," added Manning, also the author of the new book Grave Secrets of Dinosaurs: Soft Tissues and Hard Science.

There's even a chance that scientists could find a Tyrannosaurus rex—a major predator of duckbilled dinosaurs—in the same area, the University of Maryland's Holtz added.

The new discovery shows "that there is a lot more to paleontology than just looking at interesting skeletons," Holtz said.

If you're limited to bones, "you lose a lot of what you can find out about ancient creatures."