The history of palaeontology is littered with examples of famous frauds and fakes, often with eminent researchers in the field being thoroughly hoodwinked by some fairly shoddy fabrications.

One of the most famous is Piltdown Man. Discovered in a gravel pit in Sussex in 1912, a few ancient-looking fragments of a skull and jawbone quickly became hailed as evidence of a very early type of human, perhaps half a million years old. The specimens were named Eoanthropus dawsoni (“Dawson’s dawn man”), after their discoverer, amateur archaeologist Charles Dawson.

Piltdown Man was considered genuine until the 1940s, when new dating techniques and reanalysis of the bones began to provide damning evidence: the skull fragments came from a modern human and the jawbone from a young orangutan. Even without accurate dating techniques, it’s astonishing how many scientists were taken in. Back in 1912, genuine fossils of early human species had already been discovered in France and Germany. Piltdown, taken at face value, provided the eager Brits with an even more ancient and ape-like ancestor, while Dawson himself became a celebrity.

Other fakes seem even more obvious to us today. In 1725, Professor Johann Beringer, a physician and dean of the University of Würzburg, discovered a haul of marvellous fossils, describing them in a book called the Lithographiae Wirceburgensis. It’s now available to view online, and you don’t need to be able to read Latin to appreciate the fossils – there are 21 pages of illustrations at the end of the book. There are shells, leaves, worms and insects, apparently perfectly preserved, along with complete reptiles and birds, with skin, feathers and beaks intact. To the modern eye they look like fairly crude stone carvings – which is exactly what they are. But Beringer fell for it all, hook, line and sinker. Even faced with fossils of shooting stars and Hebrew letters, he rejected the possibility that the stones could be manmade. It was only after he’d published Lithographiae that it became clear that the fossil-hunter had been deceived by disgruntled colleagues who had commissioned the carvings for Beringer to find. The literally incredible collection became known as Beringer’s Lügensteine, lying stones.

Illustration of fake fossils that Professor Johann Beringer believed to be real, from his book Lithographiae Wirceburgensis, 1726.

The late palaeontologist and essayist Stephen Jay Gould wrote about more recent “lying stones” from Morocco. These range from real ammonite fossils with added embellishments to 3D plaster casts of trilobites, crabs and even small lizards, stuck on to likely-looking rocks. Some of them look similar to Beringer’s stones – and equally ridiculous. But Gould argues against criticising Beringer too roundly for his gullibility. If you know that fossils are the remains of once-living organisms, then fossilised stars and Hebrew words seem preposterous. But people were still arguing about the nature and origin of fossils when Beringer wrote his treatise. This intellectual context is crucial because Beringer’s “fossils” represented an important contribution to the debate, just as Piltdown Man appeared to satisfy big questions about human origins. These high stakes help to explain why both frauds were so eagerly seized upon.

I consider myself to be a relatively sceptical person. I like to see evidence for myself, and try to avoid speculating beyond available evidence. But I also have to accept some things on trust. One of those things is the past existence of dinosaurs. I’ve seen many dinosaur fossils, some mounted in museums, others in the process of being extracted from their rocky matrix, and it has never occurred to me that any could be anything other than genuine. I know a bit about vertebrate anatomy and I’d like to think that I’d spot if a skeleton was entirely fabricated or cobbled together from existing bits and pieces. I know quite a few palaeontologists, and most of them seem to be perfectly decent, well-balanced individuals. Even if they are the exception to the rule, I find it unimaginable that palaeontologists across the globe could be engaged in a huge global deception, hoodwinking museums into paying for dinosaur fossils – like the lying stones of Marrakech on a planetary scale.

Some, it seems, are not so quick to trust palaeontologists. These ultra-sceptics doubt the very existence of dinosaurs. And they express those doubts publicly, even on that most enlightened of fora, Mumsnet. In a February post entitled: “I’m getting sick and tired of dinosaurs being forced on our children”, CADministry wrote: “I’m really concerned about dinosaurs, and I think something needs to be done. The science behind them is pretty flimsy, and I for one do not want my children being taught lies…” In a victory for rationalism, the tone of the following discussion was amused incredulity.

I tweeted a link to the post and immediately found myself embroiled in repartee with @fakefossils – apparently Twitter spokesperson for the Facebook group Christians Against Dinosaurs. Lots of dinophiles (and some actual palaeontologists) weighed in, and on the other side @fakefossils was joined by @dinodenier, who tweeted “dinos a human invention, but motivated by greed, so yes Satan responsible”. “Stop being deliberately obtuse” tweeted @fakefossils, in response to a tweet suggesting they might be creationists.

As we sparred on Twitter, a thought suddenly occurred to me. These dino-deniers seemed too funny, too ridiculous, to be true. Were they, like Beringer’s stones, themselves a hoax? At the moment it’s a hypothesis I can’t rule out. Like any good scientist, I have to keep an open mind.