Dinosaur Mummies Found in Wyoming Reveal Unique Features

A recent study has unveiled remarkable findings about the dinosaur species Edmontosaurus annectens, known for its horse-like hooves and duck bill. Researchers discovered mummified specimens in Wyoming that are providing new insights into this unique dinosaur. The findings, published in the journal Science, highlight the mummification process that preserved these creatures in extraordinary detail.

The Edmontosaurus species, including E. annectens and its close relative E. regalis, were among the last dinosaurs on Earth before the Cretaceous-Paleogene extinction event approximately 66 million years ago. These hadrosaurids, commonly referred to as “duck-billed dinosaurs,” possessed distinctive long bills ideal for foraging for plants. Fossils of these dinosaurs have been found across several states in the western United States, including Wyoming and Colorado, and in Canadian provinces like Saskatchewan and Alberta.

Mummification Process Revealed

The two notable specimens of E. annectens from the Cretaceous era were discovered in the Lance Formation in Wyoming. The first, a juvenile estimated to be around 2 years old, and the second, an early adult between 5 and 8 years, exhibited remarkable details preserved in clay. Unlike typical fossilized bones, which harden over time, these specimens are remarkable for their preservation in sediment, revealing their outline, skin texture, and other features.

Researchers identified this unique preservation area as the “mummy zone.” Unlike human mummies, these dinosaur remains lacked organic tissues. Instead, they were enveloped in a clay layer approximately 1/100th of an inch thick. The mummification process involved a flash flood that buried the dinosaurs, followed by a biofilm that coated their remains in clay. As the organic material decayed, a 3D template of the dinosaurs’ shapes remained.

“This is a mask, a template, a clay layer so thin you could blow it away,” said Paul Sereno, a paleontologist at the University of Chicago and senior author of the study. “It was attracted to the outside of the carcass in a fluke event of preservation.”

Discovering Unique Features

Using advanced imaging techniques such as micro-CT scans and X-ray spectroscopy, researchers were able to analyze the anatomical features of E. annectens. The dinosaur showcased a fleshy crest along its neck and trunk, transitioning into a line of spikes extending down its tail. Notably, the scales were relatively small, ranging from 1 to 4 millimeters in size, with wrinkles on the ribcage indicating thin skin.

One of the most surprising revelations from the study was the reconstruction of the dinosaurs’ hooves. The findings suggest that each of the three hind toes was encased in a wedge-shaped hoof with a flat bottom, resembling the hooves of modern horses. This discovery marks significant milestones in paleontology, including the identification of the earliest hooves documented in a land vertebrate and the first confirmed hooved reptile.

“There are so many amazing ‘firsts’ preserved in these duck-billed mummies — the earliest hooves documented in a land vertebrate, the first confirmed hooved reptile, and the first hooved four-legged animal with different forelimb and hindlimb posture,” noted Sereno.

The discoveries surrounding Edmontosaurus annectens not only expand the understanding of dinosaur biology but also shed light on the conditions that can lead to exceptional fossil preservation. As researchers continue to explore the implications of these findings, they provide a fascinating glimpse into the past of these ancient creatures.