University of Chicago Researchers Uncover Exceptionally Preserved Dinosaur 'Mummies' in Wyoming
Paleontologists have reexamined century-old Edmontosaurus fossils, revealing preserved skin, spikes, and hooves encased in thin clay layers.
Paleontologists from the University of Chicago have reexamined Edmontosaurus annectens fossils discovered over a century ago in eastern Wyoming, uncovering exceptionally preserved skin, spikes, and hooves encased in thin clay layers.
The specimens, originally unearthed in the early 1900s, were found to contain not just bones but also mummified body parts protected beneath a clay mask. Among the preserved features are pieces of skin, spikes, and hooves.
The preserved soft tissues are not fossilized flesh but delicate clay molds formed by microbes during the animals' decay. This process, known as clay templating, involves biofilms facilitating the deposition of fine clay minerals adjacent to the soft tissues, capturing intricate external morphologies even within oxygen-rich river environments.
The juvenile specimen represents the first subadult dinosaur mummy with a fully preserved fleshy outline, including a neck and trunk crest. The adult specimen is the first hadrosaurid to retain its full tail spike row and is also the earliest known tetrapod with hooves, marking the first reptile with hooved feet.
These findings suggest a more complex hide for Edmontosaurus annectens than previously thought, with functional and morphological similarities to some modern squamates, the largest order of reptiles that includes lizards and snakes.
The study, published in Science, challenges traditional paradigms within taphonomy—the study of fossilization processes—and invites a reevaluation of other fossil specimens preserved in similar depositional settings.