“Medusa” — Rare 'Dinosaur Mummy' Edmontosaurus Moved to Minnesota Lab for Multi-Year Study

Medusa, a remarkably complete fossil that may preserve skin and tendon tissue, has been moved to Winona State University in Minnesota for detailed analysis.

Discovery

The specimen, identified as an Edmontosaurus and estimated to be about 66 million years old, was unearthed from the Hell Creek Formation in the Badlands of North Dakota by a team led by Winona State graduate student Adam Schroeder. At first the exposed remains did not appear extraordinary, but as the team mapped and circled the bones they found what they believe are preserved tendons and significant patches of skin — features that qualify the specimen as a possible "dinosaur mummy." Such fossils with soft-tissue preservation are extremely rare, with only about a dozen comparable finds known.

Preparation and Transport

The fossil arrived at the university encased in a protective plaster jacket measuring roughly 12 feet long by 7 feet wide. The block weighed about 14,000 pounds and was entombed in rock. Excavation and preparation at the dig site took more than a year; the team carefully lowered the jacket 85 feet down a cliff and at one point moved part of the block roughly 100 feet by hand using techniques inspired by ancient Egyptian methods. The specimen was so large that two windows in the university’s science building had to be removed to bring it inside.

Study and Display

Winona State geoscientists will lead a detailed analysis of the fossil, which the university estimates will take at least five years. The plaster jacket will remain in place as a conservation measure and may never be removed if researchers determine that leaving the cast intact best preserves the specimen. Officials also said that, when possible, the fossil will be made available for public display.

About the Edmontosaurus

The Edmontosaurus was a large herbivorous dinosaur with a duck-billed skull and numerous teeth adapted for chewing plant material. Individuals could reach lengths of around 40 feet, placing them among the largest herbivores of the Late Cretaceous on the North American Great Plains. Studying a specimen with preserved soft tissue can provide rare insights into dinosaur skin, musculature, and the environments they inhabited.

Why this matters: Soft-tissue preservation offers exceptional information about dinosaur anatomy, biology, and the ecosystems of the Late Cretaceous. The careful, multi-year examination of Medusa could significantly improve scientific understanding of Edmontosaurus and related species.