Today we explore the latest dinosaur auction that’s causing controversy in the paleontology world. Put your email here to make sure you get every Stones & Bones.
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Dubreuillosaurus was never a dinosaur superstar like Tyrannosaurus rex or Nanotyrannus. Yet this obscure French fossil is now in the spotlight for the same reason those Cretaceous celebrities recently grabbed headlines: It’s going under the auctioneer’s hammer.
Unlike Gus the T. rex and Jodi the Nanotyrannus—each of which sold for more than $45 million earlier this year—the Dubreuillosaurus valesdunensis fossil being auctioned on November 18 in Paris by the Millon auction house is the only specimen of its kind ever discovered. The fossil is considered a holotype, meaning that researchers compare other fossils with it to determine whether they belong to the same species.
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ILLUSTRATION BY MICHEL FONTAINE; PHOTOGRAPH BY D. SERETTE/R. ALLAIN
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This artist’s reconstruction of Dubreuillosaurus valesdunensis is based on a skull that is 70 percent complete. It is among the best preserved skulls of a megalosaur ever found.
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Holotypes matter to paleontologists because they are the building blocks of taxonomy and are essential to understanding how dinosaurs evolved. As such, the auction of Dubreuillosaurus is raising fears in the scientific community that the sale could open a paleontological Pandora’s box.
“It’s highly unusual. I'm not aware of any other situation, ever, where this has happened with a dinosaur holotype,” says National Geographic Explorer Steve Brusatte, a paleontologist at the University of Edinburgh in Scotland.
“I worry about the precedent this sets,” Kristina Curry Rogers, incoming president of the Society of Vertebrate Paleontology, tells me. “If scientifically unique holotypes are treated primarily as financial assets, we risk losing access to the very evidence on which our understanding of the history of life depends.”
But the auction house argues museums are often the primary beneficiaries when collectors make purchases, pointing to Apex, the $44.6-million Stegosaurus currently on a four-year loan to the American Museum of Natural History in New York. The Dubreuillosaurus fossil, it adds, has been privately owned and loaned to museums for nearly 30 years, a tradition that its new owner may choose to continue.
“In France, museums and institutions adore donors, are somewhat less fond of lenders, and have no love at all for collectors,” says Isabelle Boudot de La Motte, an auctioneer with the Millon auction house. “Yet it is the latter who purchase, preserve, restore, document, invest, lend, and eventually sell.”
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Fossil fragments and bones belonging to the Dubreuillosaurus valesdunensis holotype, the only known specimen of its kind, will be auctioned on November 18, much to the dismay of the paleontological community.
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Since the auction was announced last month (the day before International Fossil Day, nonetheless) Marie-Béatrice Forel, a micropaleontologist and the chief scientist of paleontological collections at the National Museum of Natural History in Paris, has campaigned feverishly against it.
“A holotype should never be put up for auction, as this threatens the very existence of the species as a scientific reference,” she says. For 15 years, her museum housed the Dubreuillosaurus fossil, which was given the catalog number MNHN 1998-13. Forel, her museum colleagues, the French Paleontological Association, and numerous paleoenthusiasts have published articles, promoted a petition, advocated on social media, and even raised funds to try to obtain the fossil themselves.
“Everything else has taken a back seat, as my attention has been entirely focused on the Dubreuillosaurus problem,” Forel says. “The situation is difficult, but what weighs most heavily on me is the profound gap between two perceptions of this specimen: a commercial commodity on one side, an irreplaceable heritage on the other.”
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In 1998, paleontologists from the National Museum of Natural History discovered the jaw of Dubreuillosaurus valesdunensis at a quarry in Conteville, in Normandy, France. They named it after André Dubreuil, the man who owned the quarry and had found bone fragments of the dinosaur there four years earlier. He loaned out the fossil to museums for many years until his death in 2024.
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Since its discovery in 1994 by André Dubreuil, Dubreuillosaurus has been privately owned. Dubreuil, then the mayor of the small town of Conteville in Normandy, France, was inspecting a quarry on land he recently purchased when he found dinosaur bone fragments and teeth. At his request, a team of paleontologists from the National Museum of Natural History investigated the site in 1998.
“He was very enthusiastic the first time we arrived and shared that enthusiasm with us when he welcomed us into his home, even before we had explored the quarry,” says Ronan Allain, a paleontologist from the museum who was working on his doctoral degree at the time.
One day during their dig, while Dubreuil was away, they uncovered a jaw they realized belonged to a carnivorous theropod related to the mysterious Megalosaurus. Megalosaurus is famous because in 1824 it was the first dinosaur ever named, even before scientists used the word “dinosaur.” What Allain and his colleagues unearthed was one of the best preserved skull pieces of a megalosaur ever found.
“At that very moment, we knew we had made a significant discovery, both from a scientific standpoint and in terms of the history of science,” Allain tells me. “It was our turn to share our enthusiasm with André Dubreuil when he returned.”
The team revisited the site over four more field seasons between 1999 and 2001, painstakingly sifting through rocks and debris to collect more than 2,000 fossil fragments that they brought back to their lab. The bones were so exceptionally preserved that Allain says he had little trouble reconstructing the skull. For two years, he and his colleagues spent two hours every morning assembling the puzzle pieces.
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André Dubreuil (far right), the mayor of the small town of Conteville, in Normandy, France, found the first remains of what would become Dubreuillosaurus valesdunensis in 1994. He later invited researchers from the National Museum of Natural History in Paris to excavate the site. They collected more than 2,000 fragments of the carnivorous dinosaur, which they used to identify it as a new species and holotype.
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Allain initially thought the dinosaur was a new specimen of Poekilopleuron, a dinosaur whose holotype was destroyed during a World War II bombing. But further analysis showed it was an entirely new dinosaur, which Allain formally named Dubrueillosaurus valesdunensis in a 2005 paper. The 167-million-year-old carnivore was a juvenile, about nine feet long, with an elongated snout it likely used to snatch fish, like Spinosaurus. The species likely grew to about 20 feet in adulthood.
Allain named it for Dubreuil, who owned the fossil, and for the Battle of Val-ès-Dunes, where William, the duke of Normandy (later known as William the Conqueror) won his first major victory in 1047. Dubreuil loaned his fossil to the Paris museum until 2013, when he asked that it be sent back to Normandy. There it was displayed at a regional museum called Paléospace.
After Dubreuil died in 2024, his heirs decided to sell his namesake fossil through the Millon auction house. (National Geographic reached out to Dubreuil’s heirs for comment but did not hear back before publication.) The sale is legal under French law, Allain says, because the specimen was discovered on Dubreuil’s private property and he had never legally transferred ownership to any of the museums he’d lent it to.
Allain tells me he was “nonetheless very surprised—and, more than that, deeply saddened—when I learned that this sale was going to take place.”
Other paleontologists were similarly shocked. “You hear of holotypes being lost, holotypes being stolen, holotypes being lost during the war,” says National Geographic Explorer Tyler Lyson, a paleontologist at the Denver Museum of Nature & Science. “But in terms of them actively being sold off, I've never heard of that.”
A petition to boycott the auction has so far garnered more than 4,000 signatures.
When I asked Boudot de La Motte, the auctioneer, what she would say to the paleontologists expressing concern, she told me, “I would say that instead of organizing petitions, they should set up a fund to finance the purchase of this dinosaur.” Yet a fund organized by the French Paleontological Association set up to do just that has so far raised only about $16,000 of the estimated $280,000 to $390,000 the fossil is expected to fetch.
Boudot de La Motte adds that private ownership of Dubreuillosaurus hasn’t kept it from being put on display in the past, nor does it prevent its use in future scientific collaborations. But that notion does little to alleviate apprehension among paleontologists like Brusatte.
“I am just incredibly worried that this one-of-a-kind dinosaur fossil, this name bearer for Dubreuillosaurus, will disappear into the mansion of an oligarch or the vault of a hedge fund manager, an asset to brag about or accumulate value for investment,” he says, adding that if its locked away, “this species will become a taxonomic black hole.”
If so, paleontologists may not have access to it in the future to evaluate its classification or determine whether new fossils are also members of Dubreuillosaurus.
Thomas Holtz, Jr., a paleontologist from the University of Maryland who peer-reviewed the 2005 paper that gave Dubreuillosaurus its name, told me that the fossil was key to tying together our understanding of megalosaurs. He put it this way: “If it were to disappear from scientific access, that’s just as damaging to our understanding of it as if the museum burned down and the specimen was destroyed.”
To Allain, Dubreuillosaurus serves as a major reference for paleontologists trying to understand the evolution of theropods. More than that, he adds, it’s part of the shared heritage of the people of Normandy and a record of the dinosaurs that once roamed their lands.
“Seeing it disappear into a private collection, far from the public and paleontologists, breaks my heart,” he says. “Dinosaurs are not works of art; they were not created by humans and were not produced to fulfill a commercial order.”
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LEONELLO CALVETTI, SCIENCE PHOTO LIBRARY
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Tyrannosaurus rex, the king of dinosaurs, was also known for its puny arms. But did these little limbs serve a purpose? We asked the experts.
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Your Dino Questions Answered |
In a previous Stones & Bones, we asked you to send us your biggest questions about dinosaurs and myths to debunk. We got some fantastic suggestions. Thank you for your curiosity! To help answer them, I turned to some leading paleontologists:
Q: Mila Kelly, 12, asks, “I would like to know if the arms of a T. rex were useless, weak, or had any meaning at all? If so, what were they used for and why were they so small?”
A: “When you just glance at a T. rex, its arms look pathetic,” says Steve Brusatte, a National Geographic Explorer and paleontologist at the University of Edinburgh. Although the dinosaur’s arms were short, they weren’t useless. He points out that their bones were robust and thick, with big attachment points for muscles.
And these limbs could generate a lot of force, says Thomas Holtz, Jr., a paleontologist from the University of Maryland. “The arm of an adult T. rex and my arm are comparable in size, but it’s been estimated that Tyrannosaurus could curl 100 to 200 kilograms, about 220 to 440 pounds, which would make me a superhero.”
That’s still relatively weak compared to the rest of the T. rex’s eight-ton body, but it suggests that the arms did have a role to play. “We think it’s most likely they were helping T. rex grasp onto prey as it was feeding or to grapple with other T. rexes,” Brusatte says. “The huge head of T. rex did most of the work in grabbing and biting, but the arms were accessories.”
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Paleontologists in Peru recently uncovered hundreds of inky black Ice Age fossils from a tar pit at Talara, including this dire wolf femur that belonged to a predator caught in the sticky death trap about 15,000 years ago.
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Ice Age Bone Bonanza Oozes From Peruvian Tar Pit |
Tar pits are gooey death traps that ensnared unsuspecting animals wandering into the ancient asphalt pools. In Talara, Peru, there are pits that boast an impressive array of Ice Age bones belonging to Saber-toothed cats, dire wolves, and ground sloths.
Recently, researchers retraced the route of a 1950s excursion into Talara and excavated a new tar pit oozing with hundreds of inky black bones that were 15,000 years old. “These fossils provide more than a single snapshot in time,” paleontologist Jean-Noël Martinez told National Geographic. “They show that there is a much larger story to be told at Talara.”
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STORIES WE LOVE FROM AROUND THE WORLD |
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The paleontologists who discovered the world's first adult Tyrannosaurus rex trackway enlisted the help of a helicopter to lift the fossilized footprints, each weighing more than 1,500 pounds, and then place them onto a trailer bed. The scientists then transported the footprints from the North Dakota Badlands to the Denver Museum of Nature & Science.
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World’s First Adult T. Rex Trackway Takes a Trip |
With the help of a crane, a trailer bed, and a Huey helicopter, three footprints from the world’s first ever adult Tyrannosaurus rex trackway have finally made it to their new home at the Denver Museum of Nature & Science.
With help from a high school teacher, paleontologists discovered a Tyrannosaurus trail in the North Dakota Badlands in 2025. As my colleague Dustin Renwick wrote this summer, finding any dinosaur footprint is rare enough—and this team led by National Geographic Explorer Tyler Lyson found five of them.
The researchers excavated the footprints, then wrapped them in plaster to prepare to bring them back to the museum for further study and to put them on display. They only moved three of the five footprints because those were the ones most vulnerable to weathering away. Using a helicopter, they lifted the fossilized steps, each weighing about 1,500 to 2,500 pounds, and placed them on the bed of a trailer. They used the crane to center the tracks on the trailer, which Lyson drove the full nine hours back to Denver.
“With that much mass on a trailer, they need to be centered, or you’d have a wreck going down the highway!” says Lyson. “It’s always a bit of a rodeo collecting giant dinos,” he says.
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Have a good story tip or a burning paleontology or archaeology question you’d like us to answer next? Let me know at Nicholas.St.Fleur@natgeo.com. We might tackle them in a future newsletter.
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