A recent study published in Science has unveiled remarkable findings about two mummified dinosaur specimens, specifically Edmontosaurus annectens, which lived 66 million years ago in what is now the western United States. These dinosaurs were found encased in clay, providing a unique glimpse into their physical characteristics and preservation processes.
The specimens, discovered in Wyoming, represent a late juvenile and an early adult from the Cretaceous era, both of which were remarkably preserved in sediment. Unlike the typical fossilized remains that consist of bones or teeth, these Edmontosaurus mummies showcase outlines of soft tissues, including skin, spikes, and hooves, preserved in a thin layer of clay.
The research team identified a region in east-central Wyoming, referred to as the “mummy zone,” where these specimens were located. These mummified remains, however, differ significantly from what one would expect in human mummies, as they do not contain any organic material. Instead, they are covered by a clay film that is only 1/100th of an inch thick. Researchers believe that these dinosaurs became mummies after being submerged in a flash flood, which allowed a biofilm to draw clay from the surrounding sediment to envelop their carcasses.
According to senior author Paul Sereno, a paleontologist at the University of Chicago, this preservation process created a 3D template of the dinosaurs. “This is a mask, a template, a clay layer so thin you could blow it away,” he noted, highlighting the extraordinary nature of the find.
Using advanced imaging techniques such as micro-CT scans and X-ray spectroscopy, researchers were able to reconstruct various features of E. annectens. They discovered that these dinosaurs possessed a fleshy crest along their neck and trunk, which transitioned into a series of spikes along their tail. Notably, the scales on their bodies were small, measuring only 1 to 4 millimeters across, and the presence of wrinkles on the ribcage suggested that their skin was relatively thin.
Perhaps the most astonishing discovery pertains to their hooves. The analysis revealed that the tips of each of the dinosaur”s three hind toes were encased in wedge-shaped hooves resembling those of horses. This finding marks several significant firsts in paleontology, including the earliest documented hooves in a land vertebrate, the first confirmed hooved reptile, and the first hooved four-legged animal with differing postures in its forelimbs and hind limbs.
This research not only enhances our understanding of Edmontosaurus but also sheds light on the unique conditions that led to their preservation. The implications of these findings extend to our broader understanding of dinosaur biology and the environmental factors that influenced their evolution.
