An image shows the scaly skin of a crest over the back of the juvenile duck-billed dinosaur Edmontosaurus annectens, a specimen nicknamed “Ed Jr.” by researchers. The juvenile is estimated to have been about 2 years old when it died.
Tyler Keillor/Fossil Lab
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Tyler Keillor/Fossil Lab
You might not think a paleontologist looking for 66-million-year-old fossils would need to ask a rancher about his great-grandmother’s job in the Wyoming badlands. But that’s what Paul Sereno, a paleontologist at the University of Chicago, did when he was trying to track down a historic site where a famous dinosaur mummy was found in 1908.
Sereno’s work, published in the journal Science, brings new clarity about the appearance of the duck-billed Edmontosaurus annectens, a massive herbivore from the Cretaceous period. Sereno and his team’s painstaking work reveals the dinosaur’s hooves and spiky tail in exquisite detail. They studied how a fragile clay template can create dinosaur “mummies.”
But first they had to find them.
“It involved sleuthing archives and finding photographs from these original excavations that no one knew of, and then also talking to ranchers,” Sereno says of the research.
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Looking for a post office
Sereno was hunting for the spot where the famed collector Charles Sternberg discovered a dinosaur mummy in the rough terrain of eastern Wyoming. He successfully located historical photos and a note from Sternberg detailing his journey to the site during the time of horse-drawn carriages. References to Warren, Wyo., a town that Sereno claims “doesn’t appear on any map,” led him to inquire at nearby ranches. One rancher had a great-grandmother who served as the postmaster of Warren, Wyoming, when the post office was located on a ranch. This information enabled Sereno to calculate the distance to one of the mummies discovered in 1908.
The region has since become known as “the mummy zone,” where a thick layer of river sand preserved dinosaur bodies and provided valuable insights. As technicians carefully removed grains of sand from the Edmontosaurus specimens, Sereno was captivated by their findings. He described the mummies as thin masks of the body, resembling the clay used for facial cleansing, which were trapped in the sediment without replacing the actual skin.
Detailed information about the large dinosaur was preserved in delicate clay templates, measuring just one-hundredth of an inch thick. Sereno expressed excitement over finally having a complete understanding of what a large dinosaur looked like, from head to toe, including its bill, hooves, crest, and tail spikes. He emphasized the accuracy of their depiction, with only one exception. The color is unknown. The two specimens, an adult nicknamed “Ed Sr.” and a late juvenile dubbed “Ed Jr.,” are the only juvenile dinosaur mummies ever discovered, according to the university.
During a visit to the American Museum of Natural History in New York many years ago, a young Sereno was captivated by a prize specimen that sparked his passion for paleontology. This specimen, unearthed back in 1908, still sits in the museum today, serving as a reminder of the moment that changed his life.
“That’s when I decided to be a paleontologist,” he recalls. “Little did I know that my career would lead me back to the very place where that mummy was discovered over a century ago by Charles Sternberg.”
For young fans of dinosaurs and paleontology, Sereno has a message: “If you’re an enthused kid, thinking, maybe we found everything. No, we have not.”
He emphasizes that there is still plenty of work to be done in order to make new discoveries and unravel more mysteries about the lives of dinosaurs. “For the next two generations, we’re going to be finding more things about the deep past and about dinosaurs and other creatures than ever,” Sereno predicts.
