Apex, the largest Stegosaurus fossil ever discovered, is going up for auction

In May 2022, Jason Cooper, a commercial paleontologist, went for a walk with a friend on his property near the town of Dinosaur, Colorado.

That femur led to a Stegosaurus fossil, the largest and most complete ever found, which was later nicknamed „Apex.” In July, auction house Sotheby’s will sell the Apex for an estimated $4 million to $6 million, making the skeleton the latest flashpoint in a long-running debate over the private fossil trade.

Dinosaur fossils have fetched increasing prices at auction houses since 1997, when Sotheby’s sold „Sue” Tyrannosaurus rex to the Field Museum in Chicago for $8.36 million. In 2020, „Stan”, another complete T. Rex skeleton sold at Christie’s for $31.8 million.

Such pricing has raised serious concerns among academic paleontologists, said Stuart Sumita, vice president of the Society of Vertebrate Paleontology. Many of them have noticed that fossils that could unlock scientific mysteries are moving into the hands of wealthy private collectors rather than research institutions in recent decades.

Cooper and his colleagues discovered Stegosaurus in 2023 at Sotheby’s. Excavations on his property yielded several Jurassic-era dinosaurs, many of which Cooper has donated to institutions including the Brigham Young University Museum of Paleontology in Provo, Utah, and Frost. Science Museum in Miami.

Cooper described Apex Stegosaurus as a unique and scientifically significant specimen. Skeletons — even partial ones — of plate-backed, spike-tailed herbivores are rare. The bone mound contains about 70% material of animal bones. At 11 feet tall and over 20 feet long, Apex is twice the size of „Sophie.”

The specimen was found with leather impressions from the neck, which was offered as part of the sale.

Cooper oversaw the preparation and mounting of the Stegosaurus, 3D scanning the existing bones and replicating elements of the model to fill in the gaps. The team also collected detailed contextual data, which they think will be attractive to prospective buyers. Information includes detailed site survey, quarry maps and other documents.

Cooper invited several paleontologists to examine the specimen.

„If you combine size, completeness and bone preservation, this is the best Stegosaurus I’ve ever seen,” said Rod Skeats, curator at the Brigham Young University Museum of Paleontology, who studied at Cooper’s property.

Cassandra Hatton, Sotheby’s head of science and popular culture, said the auction house worked closely with Cooper to strengthen the scientific validity of the privately sold dinosaur mount, with the aim of creating a model for future auctions.

„This is the first time that a specimen has been auctioned and we have been working together since it was excavated,” he said. „It’s the most obvious sale of a dinosaur that’s ever happened.”

But Jim Kirkland, Utah’s state paleontologist, refused to support Stegosaurus when called upon by Cooper. „This is very interesting,” he wrote in an email.

While anything can happen at public auction, both Cooper and Hutton expressed hope that Apex will land at a scientific institution — either through outright purchase or a donation from a private collector. The group collected data and documents not only to assure buyers of the specimens’ authenticity, but also to help museums smoothly integrate such specimens into a research collection.

„The buyer has the right to come onto my property and collect situational information,” Cooper said. „A private collector might not give a stego spike about it, but for a museum, it’s pretty cool.”

However, Stegosaurus’ potential price tag may be out of reach for many companies, Sumita said. He said the costs of studying an already loaded and reconstructed sample would exceed the purchase price. Reconstructing and mounting fossils is as much art as science—and specific choices can be used to deceive the uninitiated by blurring the lines of which parts of a particular bone are authentic.

„If that model is scientifically significant, they’re going about it completely the wrong way,” Sumita said.

Gary Woodruff, curator of vertebrate paleontology at the Frost Museum of Science in Miami, admits that public auctions are often „scientific hermits.” But Woodruff — who examined the specimen before the auction deal — suggested that compiling detailed records, images and digital scans of fossils sold commercially is something other sellers should follow. That way, „if the model doesn’t end in public trust, there may at least be a semblance of scientific data,” he said.

Ultimately, however, Woodruff conceded that it was public faith where such fossils belonged.

„If a rich person is interested in how they can work with a scientific organization to contribute to scientific knowledge and progress, I believe such models will attract their attention.”