Duck-billed dinosaur ‘mummies’
October 29, 2025
Called dinosaur “mummies,” two skeletons of the duck-billed dinosaur Edmontosaurus were discovered in Wyoming more than a century ago preserved like sun-dried carcasses. The snout of one is covered with a ducklike bill and both have large areas of scaly integument described as “skin impressions.” Revisiting this area uncovered a “mummy zone,” with finds including two additional Edmontosaurus mummies and exceptional specimens of the contemporaries Triceratops and Tyrannosaurus. How soft tissues fossilize, and whether any of the original organic materials survive, remain open questions.
See the full article in Science.
A mummy of the juvenile duck-billed dinosaur Edmontosaurus annectens was preserved as a dried carcass some 66 million years ago in the badlands of Wyoming. Large areas of scaly, wrinkled skin and a tall, fleshy crest over its back were preserved in a thin layer of clay over its fossilized skeleton.Photo courtesy of Tyler Keillor/Fossil Lab
Paleontologist Paul Sereno of the University of Chicago with the dinosaur mummy, nicknamed “Ed Jr.,” which was covered by floodwaters some 66 million years ago.Image courtesy of the UChicago Fossil Lab
Fossil preparator Tyler Keillor of the University of Chicago with the dinosaur mummy, nicknamed “Ed Jr.,” which was covered by floodwaters some 66 million years ago.Image courtesy of the UChicago Fossil Lab
The scaly skin of a crest over the back of the juvenile duck-billed dinosaur, estimated to be about 2 years old at the time it died. It is the only juvenile dinosaur mummy ever discovered.Image courtesy of Tyler Keillor/Fossil Lab
UChicago paleontologist Paul SerenoPhoto courtesy of Kieth Ladzinski
Fig. 1. Dinosaur “mummy zone” in the Lance Formation of east-central Wyoming.
Fig. 2. Midline crest and spike row in E. annectens with extant squamate analog
Fig. 3. Pedal hooves, digital pads and fleshy profile in E. annectens.
Fig. 4. Microstructure and geochemistry of spike integument renderings in E. annectens (UCRC PV30).
Dinosaur mummies unmasked. Mummies of the duck-billed dinosaur Edmontosaurus
annectens (1) document with a thin external clay template a fleshy crest over neck and trunk (2),
a fleshy spike row over hips and tail (3), and hooves capping the toes of the hind feet (4).
Preserved as desiccated carcasses (5) and rapidly buried rapidly by floodwaters (6) on a coastline
(7), the duck-billed mummies come from the very end of the dinosaur era in what today is east-
central Wyoming. (artwork by Dani Navarro)