Edmontosaurus “Mummy” Fossils Reveal Large Fleshy Crest and Row of Tail Spikes – Real Appearance Shocks Scientists

Two extraordinary “mummy” specimens of the duck-billed dinosaur Edmontosaurus annectens have finally revealed the true external appearance of one of the most common Late Cretaceous herbivores. Preserved in exquisite detail, the fossils show a prominent fleshy midline crest running along the back and a striking row of interlocking spikes extending down the tail — features that have stunned paleontologists.

The specimens, recovered from Wyoming’s Lance Formation, were described in Science (23 October 2025) by Paul C. Sereno and colleagues. A sub-millimetre clay film formed during early decay captured every contour of the body before soft tissues disappeared. The result is a three-dimensional “mask” showing pebble-like scales, wrinkled skin, and soft-tissue structures in unprecedented detail.

Most dramatically, a continuous fleshy crest runs from the neck over the trunk and transitions at the hips into a single row of interdigitating spikes that extends all the way to the tail tip. The hind feet preserve the first known true hooves in any dinosaur — wedge-shaped structures that would have aided traction on muddy floodplains.

These features transform our image of hadrosaurs from plain, unadorned duckbills into ornate, hoofed herbivores with dynamic midline ornamentation. The “mummies” are now housed at the University of Chicago and partner insтιтutions, offering the clearest view yet of what a living dinosaur actually looked like just before the asteroid impact 66 million years ago.