Wyoming Discovery Reveals New Insights into Edmontosaurus Mummies

Paleontologists have made a groundbreaking discovery in Wyoming, uncovering two remarkably preserved mummies of the duck-billed dinosaur, Edmontosaurus annectens. This significant find, led by Paul C. Sereno, a professor of organismal biology at the University of Chicago, offers new insights into the appearance and anatomy of this herbivorous dinosaur, which lived during the late Cretaceous period.

The initial specimen of Edmontosaurus was unearthed in 1908 by fossil collector C.H. Sternberg. This skeleton, later displayed at the American Museum of Natural History in New York and nicknamed the “AMNH mummy,” featured imprints of scaly skin in the surrounding sediment. Over a century later, Sereno’s team returned to the same site and found two additional mummies, which preserved intricate details of the dinosaur’s external anatomy.

Uncovering the Past

The newly discovered mummies were embedded in a thin layer of clay that captured the fleshy external features of Edmontosaurus with remarkable precision. For the first time, researchers gained a comprehensive understanding of the dinosaur’s appearance, including the size of its scales and the arrangement of spikes on its tail. Sereno expressed excitement about the accuracy of this new image, stating, “I think now we finally nailed down the way it truly looked.”

The journey to rediscover the site was challenging. Sereno and his team navigated Sternberg’s historical notes, which referred to locations that have since vanished from maps. Their efforts paid off when they located the “mummy zone,” an area rich in Cretaceous fossils within a radius of less than 10 kilometers. Sereno emphasized the importance of geology in finding dinosaurs, noting that the area’s geological processes were exceptional.

The Secrets of the Lance Formation

The mummies were found within the Lance Formation, a geological layer formed in the final million years of the Cretaceous period. Stretching across several states, including North Dakota, South Dakota, Wyoming, and Montana, the formation exhibits a remarkable thickness, particularly in the “mummy zone,” where it reaches up to 1,000 meters. This indicates a high sedimentation rate, likely caused by frequent flooding from a nearby river.

Sereno explained that these floods could have buried the dinosaurs in mud and clay, preserving their bodies through a process known as “clay templating.” This method retains a thin layer of skin detail, akin to the techniques used to study deep-sea invertebrates. “It’s just no one ever thought it could happen to a large dinosaur buried in a river,” Sereno remarked.

The team utilized advanced imaging technologies, including CT scans and photogrammetry, to analyze the mummies. The findings revealed surprising features of the Edmontosaurus that challenge previous interpretations. For instance, they discovered that the dinosaur possessed hooves, an attribute not previously associated with this species.

Sereno noted that the fleshy crest began at the head and extended along the spine, transitioning into a row of spikes similar to those found on modern chameleons. Additionally, the scales of Edmontosaurus were surprisingly small, measuring just 1 to 4 millimeters, and the skin was notably thin.

The revelation of these features marks a significant update in the understanding of this dinosaur’s morphology. “There are so many amazing ‘firsts’ preserved in these duck-billed mummies,” Sereno stated, highlighting the evolutionary significance of their findings.

Future Discoveries Await

The team’s exploration did not stop with Edmontosaurus. Sereno reported finding other remarkable specimens in the mummy zone, including a T. rex and a Triceratops. These mummies are currently under investigation and will be discussed in forthcoming publications. The T. rex mummy was found in a life-like pose, indicating it may have been buried alive, while the Triceratops mummy has already shown unique characteristics, including larger scales and thicker skin.

Sereno emphasized the potential implications of these finds for understanding the physiology of different dinosaur species that coexisted. “We are in the age of discovery. There are so many things to come. It’s just the beginning,” he concluded, hinting at the exciting developments that lie ahead in the study of these ancient creatures.

As research continues, the implications of these discoveries will undoubtedly reshape the narrative of dinosaur evolution and ecology, revealing more about the lives of these fascinating animals that once roamed the Earth.