Rare 66-Million-Year-Old Edmontosaurus 'Medusa' Arrives at Winona State — Possible Dinosaur Mummy

Winona State Welcomes a Remarkable Dinosaur Discovery

A massive dinosaur that walked the Earth about 66 million years ago is now housed in a laboratory at Winona State University after one of the largest and rarest fossil discoveries in recent memory. The specimen has been identified as an Edmontosaurus and nicknamed Medusa by the research team.

From snout to tail this duck-billed herbivore measured roughly the length of a city bus. It lived during the Cretaceous Period alongside famous contemporaries such as Tyrannosaurus rex and Triceratops, and it existed shortly before the mass extinction that ended the reign of large non-avian dinosaurs.

How the Fossil Was Found

Adam Schroeder, a 2013 Winona State geoscience graduate and founder of Hell Creek Fossils, discovered bones protruding from the ground while prospecting on private land near Marmarth, North Dakota, in July 2024. Schroeder led the excavation, which recovered an unusually complete and articulated section of skeleton — including parts of the back, hips and limbs — rather than the isolated bones typically found.

Why This Find Is Extraordinary

Winona State geoscience professor Lee Beatty, who helped excavate and install the specimen at the university, emphasized two rare features: the skeleton’s articulation (bones found in life position) and the potential preservation of skin and soft tissues. If confirmed, the fossil would qualify as a "dinosaur mummy", a very uncommon type of specimen that can reveal details about soft anatomy, skin texture and biology that bones alone cannot.

"There are only a few of these worldwide, and we very well may have one here," Beatty said, noting the discovery's scientific and educational value.

The team reports the specimen was found headless with most of the tail missing, and that the remote, rocky outcrop where it was discovered was crawling with rattlesnakes.

From Field To Lab

The fossil now resides in Winona State’s Science Laboratory Center. Because the specimen and its protective plaster jacket were too large to pass through standard entrances, a window was temporarily removed to bring the fossil inside. Preparators will now begin careful mechanical and chemical work to remove surrounding rock without damaging any preserved soft tissues.

"We're going to be really carefully removing as much rock as we can from the fossil. And fingers crossed, if we find more skin, then we're really going to be able to see it," Beatty said.

Public Display And Educational Impact

The university plans to prepare the specimen for future display so students, researchers and the public can see the find up close. Beatty said he hopes Medusa—and the public interest it generates—will inspire curiosity about science and open doors for people who had not previously considered fields like paleontology.

Context

Edmontosaurus lived during the late Cretaceous Period (about 145 million to 66 million years ago). At its largest, the genus could reach lengths comparable to a city bus and in length rivaled large theropods such as T. rex, though it differed in build and ecology. The Hell Creek Formation in North Dakota and surrounding regions remain some of the richest sources of late Cretaceous fossils in North America largely because arid conditions and sparse vegetation make bone-bearing rock easier to find.