Paleontologists studied two remarkable specimens of end-Cretaceous duck-billed dinosaurs, Edmontosaurus anectens. They employed various imaging techniques to reconstruct the species’ physical appearance during its life, showcasing features such as the prominent crest over the neck and torso, a row of spikes on the tail, and the hooves covering the toes. Alongside fossilized footprints, Edmontosaurus anectens is now in my grasp.

“This marks the first time we’ve been able to capture a comprehensive and specific depiction of a large dinosaur,” stated researchers from the University of Chicago, including Professor Paul Sereno, the lead author of the study.

“The badlands of Wyoming, where this discovery occurred, serve as a unique ‘mummy zone’, promising additional surprises from fossils collected over years by a team of university undergraduates.”

Professor Sereno and colleagues utilized historical photographs and field research to outline a compact “mummy zone” in central-eastern Wyoming, home to several notable dinosaur “mummies” unearthed in the early 20th century.

They discovered two new mummies within piles of river sand: Edmontosaurus anectens — consisting of juveniles and adults — which preserved a large, continuous area of the external skin surface.

Using these specimens, they reconstructed a complete, fleshy profile of the species.

“The two specimens complemented each other exceptionally well,” Professor Sereno remarked.

“For the first time, we could visualize the entire outline rather than isolated patches.”

Paleontologists identified a continuous midline feature that begins as a fleshy crest along the neck and torso, transitioning into a row of spikes across the hips and down the tail. Each spike was identified on a single vertebra and interlocked with one another.

The lower body and tail featured the largest polygonal scales, while the majority were small, pebble-like scales just 1 to 4 millimeters in diameter, surprisingly tiny for a dinosaur exceeding 12 meters (40 feet) in length.

Wrinkles on the thorax indicate that this dinosaur had thin skin.

The hind legs of the significant “mummy” revealed the most unexpected finding: hooves.

The tips of each of the three hind legs were encased in wedge-shaped hooves with flat soles, akin to a horse’s.

Researchers utilized CT scans of the specimen’s feet and 3D images of the best-preserved footprints from the same era to accurately map the former to the latter.

Data from both sources enabled precise reconstruction of the hind paw’s appearance.

In contrast to the front feet, which made contact with the ground solely via the hooves, the hind feet featured thick heel pads behind the hooves.

“These duck-billed ‘mummies’ reveal several remarkable ‘firsts’: the oldest hooves ever found in a land vertebrate, the first ungulate reptile identified, and the first ungulate quadruped exhibiting distinct front and hind limb postures,” Professor Sereno asserted.

The team’s paper was published in today’s magazine, Science.

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Paul C. Sereno et al. 2025. The fleshy midline and hooves of a duck-billed dinosaur reveal a template for terrestrial clay ‘mummification.’ Science, published online October 23, 2025. doi: 10.1126/science.adw3536