Driving more speculation, they worry, could further spike the already rising prices of fossil digs and lead to the duping of investors.
Experts at Sotheby’s respond that such sales – by attracting the interest of potential donors – inject more philanthropy in the field of palaeontology.
Prospectors discovered the ceratosaur, which the sellers have chosen not to nickname, in 1996 near Bone Cabin Quarry, Wyoming.
It is only the fourth Ceratosaurus skeleton ever found, and the only juvenile. The 3m-long animal is notable for its complete skull, made up of 57 “paper thin, super delicate” bones, Sisson said.
It was acquired by the Museum of Ancient Life, where Sisson worked on its display as a teenager. Years later, he formed his own commercial palaeontology company, Fossilogic, and he had not forgotten the ceratosaur.
“This is a pretty interesting specimen scientifically, but it was just kind of sitting there and not getting any attention,” Sisson said.
In 2024, the museum sold Sisson the dinosaur for an amount he declined to disclose.
Some researchers have questioned the decision to place a museum specimen in private hands.
The decision to sell to a “longtime trusted friend and partner to the museum” was made with the “unanimous approval” of the board of trustees, said McKay Christensen, the chief executive of Thanksgiving Point, which owns the museum.
The proceeds of the sale, he said, “are critical and necessary to our ongoing sustainability, and exclusively reserved and used to maintain and protect our collections, educate visitors and further expand our collections”.
“This juvenile ceratosaur is a truly remarkable specimen,” said Cassandra Hatton, vice-chair and global head of science and natural history at Sotheby’s.
She noted that because the Museum of Ancient Life lacks paleontological certification as a public repository, the specimen has never been fully described or studied.
She pointed to the sale of “Sue” the Tyrannosaurus-Rex to the Field Museum in Chicago and the current four-year loan of “Apex” the stegosaurus to the American Museum of Natural History as evidence of the auction house’s “track record in helping to get specimens such as this into the public trust”.
Sisson and his team rebuilt the skeleton, used 3D printing and sculpted elements to fill in the missing bones and mounted the genuine fossils in jewellery-grade metal brackets, allowing the bones to be removed individually and, he said, preserving them for research purposes.
As with “Apex,” the specimen will be offered with supplementary records and documentation of its original excavation by Western Paleontological Laboratories, and Sisson’s reconstruction. That paperwork helps maintain its scientific integrity, Hatton said.
It also increases the fossil’s value.
Andre LuJan, president of the Association of Applied Palaeontology, a trade group that represents preparators, fabricators and many commercial palaeontologists, said that raising the threshold for documentation on dinosaurs brought to market had had a positive effect by preventing some disputed material from going to auction.
But he and others in the field also see an “Apex effect” after the stegosaurus sale, and they fear the ceratosaur auction could worsen it.
The prices of leases for land, where palaeontologists find new scientifically important specimens, were already rising enough to harm academic researchers. Now it is squeezing commercial operators too, LuJan said.
“Landowners see the market rise and think, ‘Oh, we’re not charging enough for our leases,’” LuJan said. “But they don’t understand the volatility of the market.”
Some entities are also beginning to promote fossils as potential investment opportunities.
Last December, US$2.75m in shares were sold to fund the excavation of a Wyoming stegosaur, according to the website Cowboy State Daily. The excavators – who kept 80% of the shares – said they believed it could sell at auction for as much as “Apex”.
That approach “democratises access to high value assets”, said Peter Lovisek, a fossil dealer and appraiser who worked with a European company, Konvi, on similar sales.
While the sale of fossils at auction remains widely accepted among commercial palaeontologists, LuJan said, he is troubled by the selling of speculative shares in advance.
“It’s a way to take advantage of people’s optimism,” LuJan said. “But a lot of people are going to get left holding the bag.”
A comparable example was the downfall of Aristophil, a French company that sold shares in auctioned manuscripts in what prosecutors described as a literary Ponzi scheme.
Commercial dinosaur sales also are unpredictable, said Lukas Rieppel, a historian of palaeontology at Brown University. No specimen is easily comparable with another, and the build-up of hype makes assessing fair market values difficult.
“If it’s been in a museum, if it’s been described in a scientific or artistic journal, if it’s been written about in a newspaper of record like the New York Times, that may end up driving up the price,” Rieppel said.
Stuart Sumida, president of the Society of Vertebrate Palaeontology, noted that his society had long opposed sales like the one involving the ceratosaur.
They have the effect, he said, of making it more difficult for researchers to acquire important specimens and sometimes removing dinosaurs “from the public trust and the scientific community for profit”.
But Sotheby’s, which will auction the ceratosaur on July 16, defends the sales.
“Our clients, which include both institutional and private buyers, share the same appreciation and deep respect for these specimens,” Hatton said.
“If it’s in a museum and people can see it, that’s great,” Sisson said. “If a passionate person buys it and wants to appreciate it, that’s fine.”
This article originally appeared in The New York Times.
Written by: Asher Elbein
Photographs by: Matthew Sherman/Sotheby’s
©2025 THE NEW YORK TIMES
