What kind of animal had horse-like hooves, a duck’s bill, and miniature scales all over its body? The answer is not a fictional creature with different parts put together like Frankenstein’s monster, but rather a Edmontosaurus annexesa dinosaur that once roamed the western United States. Things get even stranger with this strange species: a few of its kind have been found mummified under a covering of clay.
A new study published in Science brought to light the disturbing story of E. annexes specimens that have been preserved in such a way that they are essentially dinosaur “mummies.” Researchers analyzed two specimens discovered in Wyoming, as well as several others buried in an area they dubbed the “mummy zone.”
An unlikely dinosaur fossil
The two known species of Edmontosaurus — E. annexes And E. regalis – were among the last dinosaurs to exist before the Cretaceous-Paleogene extinction wiped out all non-avian dinosaurs 66 million years ago.
Both species were hadrosaurids, otherwise known as “duck-billed dinosaurs.” True to their name, Edmontosaurus sported long beaks that were useful for picking plants to eat. Their fossils are found today in several states in the western United States (such as Wyoming and Colorado) and in the Canadian provinces of Saskatchewan and Alberta.
Two E. annexes The specimens discovered in Wyoming are particularly distinct because of the way they were preserved. A late juvenile (about 2 years old) and young adult (5-8 years old) from the Cretaceous Lance Formation attracted the attention of paleontologists because their bodies were impeccably delineated in the sediments.
Usually, paleontologists are accustomed to seeing dinosaur remains in the form of fossilized bones or teeth, which can last for millions of years, unlike soft tissues, which decompose easily. Both E. annexes the mummies, however, are outliers; many of their features, including skin, spikes and hooves, were drawn in clay, providing researchers with a rare form of mummified preservation.
Learn more: The Japanese mermaid’s mummy turned out to be papier-mâché
Looking for dinosaur mummies
In the new study, researchers mapped a location in east-central Wyoming that they call the “mummy zone,” which is home to the E. annexes specimens.
These dinosaur mummies, however, do not resemble human mummies. They retained no organic tissue, but their bodies were preserved as a clay film only 1/100th of an inch thick.
How did these dinosaurs become mummies, exactly? Researchers determined that their carcasses had been engulfed in a flash flood, and soon after, a biofilm extracted clay from the surrounding sediment to cover them. While the organic matter underneath eventually dissolved, a 3D model of the carcasses remained.
“This is a mask, a model, a layer of clay so thin that it could be removed,” lead author Paul Sereno, a paleontologist at the University of Chicago, said in a statement. “It was drawn to the outside of the carcass during a preservation accident.”
The first clogs in history
Using imaging tools such as micro-CT scans and X-ray spectroscopy, researchers were able to describe several characteristics of E. annexes.
E. annexes had a fleshy crest that lined the neck and trunk, transitioning into a single row of spikes that ran down the length of the tail. Most of their scales were tiny, measuring only 1 to 4 millimeters in diameter, and the wrinkles on the ribcage suggest their skin was thin.
Most surprising, however, were the dinosaurs’ hooves, which researchers were able to reconstruct using CT scans and 3D images of other duck-billed dinosaur footprints. The tip of each of the dinosaur’s three hind toes is said to have been enclosed in a flat-bottomed, wedge-shaped hoof, similar to horses’ hooves.
“There are so many amazing ‘firsts’ preserved in these duck-billed mummies — the first documented hooves in a land vertebrate, the first confirmed hoofed reptile, and the first four-legged animal with different forelimb and hindlimb postures,” Sereno said.
Learn more: Mummified dogs reveal that pre-Incan people honored this shepherd 1,000 years ago
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