On Wednesday, a team of scientists unveiled a newly discovered dinosaur that had the body and sickle-clawed feet of Velociraptor, the head and snout of a swan, and weird arms that were somewhere between grasping limbs and flattened flippers. This bizarre murder-swan, which the team christened Halszkaraptor, was so odd that when they first saw it, they suspected that it was a fake—a Frankensaur that had been assembled from parts of different dinosaurs. “All of us thought, when we first saw it: Oh come on now,” says Philip Currie from the University of Alberta.

But after using a particle accelerator to scan the animal, and the rock in which it is still encased, Currie and his colleagues are convinced that it’s the real deal.

Not everyone is so sure, though. When Steve Brusatte from the University of Edinburgh first saw a picture of Halszkaraptor, his spidey sense also started tingling. Its posture, from the curve of its tail to the way its claws were almost perfectly fanned out, looked strange, as if it was ready for display. Its body looked like that of Velociraptor, but its skull looked like one from a different dinosaur group—the alvarezsaurs. And most worryingly of all, the specimen has a convoluted history. It was poached from Mongolia (as many dinosaurs are), and smuggled into Japan and Britain, before ending up in a private collection in France—a meandering route that offered few reassurances and many chances for tampering.

“This new discovery has thrown a lot of us for a loop,” he says. “It’s either really a new dinosaur, which would be awesome, or it’s been tampered with and I really hope that’s not the case. The authors worked really hard to demonstrate that it hasn’t, using the best tools at their disposal. But I wonder if we have the right tools, since the fakes are so sophisticated.”

No matter their views on Halszkaraptor, everyone I spoke to agreed that fossil forgery is a surprisingly serious problem. There’s a long history of hoax fossils, like the infamous Piltdown Man—a human skull that was glued to an orangutan’s jaw, and presented as a missing link in human evolution. That was in 1912, but a century on, fake or doctored specimens still abound in fossil shows, private collections, and even in small regional museums.  

These bogus specimens aren’t cries for attention. “In my experience, I’ve never seen a single specimen that was made by the scientific community to get more publicity,” says Mark Norell, a curator at the American Museum of Natural History. Instead, they’re almost always the work of people trying to earn a buck—often poor farmers in China.  

There is a lucrative market in fossils, which owes much of its existence to Sue, a beautifully preserved Tyrannosaurus that was unearthed in 1990 and auctioned for $7.6 million. After her sale, “a modern gold rush began, and it has not let up,” wrote Paige Williams in The New Yorker. Fossils became status symbols, attracting wealthy buyers and unscrupulous vendors. An extensive black market arose, connecting fossil-rich sites like China and Mongolia and anyone with money to burn and a penchant for trophies from another age.  

The fakes are sometimes created from whole cloth—or rather, from whole plaster. These are usually crude and easy to recognize. Currie remembers seeing photos of an alleged Archaeopteryx—a pivotal species which helped to show that birds evolved from other dinosaurs. It was in Beijing, but after Currie flew over, “within three seconds of seeing it, I knew it was 100 percent fake,” he says. The weight of it was wrong. The texture of the bone was wrong. No actual paleontologist would be fooled, but Currie found several such fakes in tourist shops, all with expensive price tags.

In many ways, the market in forged fossils is similar to the one in forged artworks, says Norell, who has a foot in both worlds. When he attends the gargantuan annual fossil show in Tuscon, he takes the same equipment that he uses to examine fine art, like a special ultraviolet light. “I have a carbide needle that I can heat up with a lighter and push onto something,” he says. “If it’s real, guys will let you do it. If it has epoxy, they won’t.”

Some phonies are harder to spot. Currie recalls seeing a Tarbosaurus—a Mongolian relative of Tyrannosaurus—that “looked pretty good and was sold for hundreds of thousands of dollars.” When his team analyzed it with a medical scanner, they showed that just a single bone in the jaw was real. “It was convincing enough that we couldn’t be sure how much was real and how much wasn’t.”

More often, actual fossils are touched up to make them more dramatic. Another Tarbosaurus, which was famously seized by the American government in 2012, was mostly real, but its teeth, fingers, and toes had all been reconstructed. Feathered dinosaurs are all the rage, so artisans will sometimes paint the outlines of feathers on their fossils. One dinosaur had a crest added to its skull by fossil-poachers, who wanted to make it look more dramatic and complete; scientists spent so much time removing the extra material that, in a bit of questionable victim-blaming, they named the beast Irritator. And by some estimates, around 80 percent of the marine reptile specimens that are on display in local and regional Chinese museums have been “altered or artificially combined to varying degrees.”

The vast majority of sham fossils are chimeras—two or more actual specimens that have been glued together to make them seem new. Sometimes, the work is ... not well-researched. Currie once saw a Confuciusornis—a crow-sized Cretaceous bird—that was clearly fake because its foot had been glued directly to its knee, with no shinbone in the middle. It was on display in a Chinese museum.

But these pseudosaurs can be far more convincing. In the Gobi desert of Mongolia, dinosaurs are often found in soft sandstone. Fakers have been known to crumble this rock and then re-harden it to glue separate specimens together. “It can be really hard to tell if that’s fake,” says Brusatte. “Is that original sandstone or sandstone that’s been put back together?”

Mostly, these counterfeits have little impact on what we know about dinosaurs. They don’t feature in high-profile papers, and they stay out of the limelight. But there are exceptions. In 1998, the owners of a small Utah museum acquired a specimen from China. The beast was never described in a scientific journal, but that didn’t stop National Geographic from hosting a press conference about it, or featuring it in the magazine as Archaeoraptor—a “true missing link in the complex chain that connects dinosaurs to birds.”

“The specimen was suspicious right from the beginning,” says Currie, who was one of the scientists called in to examine it. The tail didn’t seem to connect to the body. The feet were exactly symmetrical in a way that real limbs just aren’t, as if one had been made using the other as a template.

It turned out that Archaeoraptor was the dinosaur equivalent of a horse costume, with the front and back halves played by different actors. Someone had glued the head and upper body of Yanornis (a primitive bird) to the tail of Microraptor (a four-winged Velociraptor cousin) and the legs and feet of an unidentified animal. Some missing parts had been filled in with a paste that was made from ground-up bone. It looked like bone at first glance because it was, but a medical CT scanner revealed the trickery: The fakes lacked the complex internal structures of real bones.

“The Archaeoraptor fiasco really brought the issue home to dinosaur workers,” says Brusatte. “There hasn’t been a big forgery like that in dinosaurs in the last 15 years. But we’re due for something like this to come up again and I just hope that it’s not me who’s fooled by it.”

He has reason to worry because by his own admission, some of the fakes are “really, really good”—good enough to fool even the trained eye. And the wider problem is that no one really knows which techniques are good enough to distinguish fossils from faux-sils. CT scans helped to pierce the Archaeoraptor illusion, but “looking at a CT scan is oftentimes like looking at a Rorschach test, or at tea leaves,” says Brusatte. “You can see many things in there.” Would it be good enough to detect sandstone that had been joined together with reconsolidated sandstone? Who knows?

That’s why Currie and his colleagues scanned Halszkaraptor using a synchrotron, producing scans that are much higher in resolution. “You can look at the continuity of the bones and the rocks, and whether there’s any gluing or infilling,” he says. They could even show that the chemical composition of the rock is consistent across the fossil. To fake that, someone would have had to find two specimens from the same site, and join them together using rock that also had the same origins.

Currie is highly respected among his peers, and his name gives weight to the claims around Halszkaraptor, even among the skeptics. I asked him how certain he is that the specimen is real, on a scale of 1 to 10. “I’m at least a 9,” he tells me. “You can never say that you are 100 percent sure, because some of these people are really incredible artisans.”

“You’re running to catch up with the forgers,” says Brusatte. “I don’t know what the definitive evidence would be either way, or what sort of burden of proof would be enough. The only thing that can prove that it’s genuine is another team finding another skeleton and digging it up themselves. And I hope that happens.”