The sun-scorched mines of Morocco’s Oulad Abdoun Basin are some of the richest fossil-hunting sites in the world.
Laid down between 70 and 50 million years ago, the basin’s rocks are valued for their phosphate but also for preserving the remains of prehistoric marine life, including those of mosasaurs – large swimming reptiles that were contemporaries of Tyrannosaurus rex.
Tens of millions of years later and thousands of kilometres away, the partial jawbone of one such creature has been the focus of a made-in-Canada dispute over whether or not the fossil is genuine.
On one side, an international team of scientists that unveiled the bone four years ago stand by their conclusion that it represents a new type of mosasaur. On the other side, a pair of graduate students and a professor at the University of Alberta say the photographic evidence points to a forgery.
Now, the fossil’s champions say they are about to put the legitimacy of their find to the test.
The debate offers a glimpse into a world where scientists vie with private collectors for traces of the distant past while trying to separate bona fide discoveries from specimens that have been altered to increase their value. Under such circumstances, diverging interpretations of an isolated piece of bone can lead to very different ideas about how an extinct species lived – or whether it existed at all.
“That’s how science works: people questioning each other, people butting heads. Because this is the only way the truth can come out,” said Henry Sharpe, one of the Alberta students challenging the fossil’s authenticity.
Henry Sharpe, Mark Powers and Michael Caldwell at the University of Alberta had suspicions about the new mosasaur find and set out to learn more.Darren Jacknisky
Mr. Sharpe said he first got interested in the matter while doing field work last year in Alberta’s Dinosaur Provincial Park. During a rainy day when he was confined to his trailer, he picked up a January, 2021, research paper describing the fossil in the journal Cretaceous Research.
The authors of the paper, led by Nicholas Longrich, a paleontologist and senior lecturer at the University of Bath in Britain, proposed that the fossil represents a previously undocumented species of mosasaur. Its characteristic feature is the arrangement of bladelike teeth within the jawbone.
They are “unlike those of any known reptile,” Dr. Longrich and his colleagues wrote, suggesting that the mosasaur used its unusual teeth in a sawlike fashion to cut away chunks of flesh while hunting or scavenging larger prey. They dubbed the species Xenodens calminechari, a name cobbled together from the Greek xenos, for “strange,” Latin dens, “tooth,” and Arabic calminechari, “like a saw.”
This fossil of a partial upper jaw with four teeth formed the basis for Nicholas Longrich's case that Xenodens is a newly discovered species of mosasaur.Courtesy of Nicholas Longrich
To Mr. Sharpe’s eyes, it was the fossil itself that looked cobbled together. Based on photographs included in the study, its four preserved teeth appear to have sprouted out of only two sockets in the jawbone. In vertebrates, one tooth per socket is the rule.
“Either it was a fake and they hadn’t recognized it, or it was real and exceptionally strange,” Mr. Sharpe said.
When he was back in Edmonton, Mr. Sharpe discussed the fossil with University of Alberta paleontologist Michael Caldwell, who was aware of the Xenodens paper and had similar doubts.
Their skepticism was heightened by the fossil’s uncertain provenance. As noted in the study led by Dr. Longrich, it had been collected by workers at the Sidi Chennane phosphate mine in Morocco rather than by paleontologists. The fossil’s history before it was examined by Dr. Longrich and his colleagues is uncertain.
Together with PhD student Mark Powers, Mr. Sharpe and Dr. Caldwell then published a peer-reviewed paper in The Anatomical Record last December detailing their objections to the fossil. To them, it seemed that the fossil’s peculiar teeth had been “artificially placed” in the jawbone. In their paper, they drew attention to a slight colour and texture difference that is evident on the bone near the base of the teeth, which they say could be a sign that an adhesive was used to attach the teeth in their current position.
Fossils that define a newly discovered species are called type specimens. Because of the potential for forgery, any species based on a type specimen that was “commercially collected” should be treated with extreme caution, the Alberta team warned.
Dr. Longrich has published research on a variety of fossils that have emerged from Morocco's phosphate beds: This one belonged to Thalassotitan atrox, whose short, conical teeth he likened to a killer whale's. He rebuffs the Albertans' argument that his latest find is not what it seems.Dr Nicholas Longrich via Reuters Connect
Dr. Longrich has strongly rejected this characterization of the fossil along with any allegations of fakery.
Together with his co-authors, he wrote in a statement that the Alberta group’s conclusions are based “only on second-hand observations, speculation and misinterpretations of low-resolution published images.”
The statement further added that the discoloration that the Alberta team said was evidence of an adhesive was instead caused by a hardening agent.
Dr. Longrich and his co-authors also wrote that during the fossil’s preparation, one of the teeth became detached, exposing more of the bone underneath.
“If any reconstruction had taken place, it would have been obvious,” they said in their statement.
“Xenodens would hardly be the first time that scientists have found nature too strange to be true,” the authors concluded. “In science one should remember that evolution is cleverer and more creative than we are and produces things far stranger than we can imagine.”
Dr. Caldwell is known for his work on the evolution of snakes from marine lizards, like this one illustrated for a 1997 paper in the journal Nature. In 2021 his expertise put him at odds with Dr. Longrich about a fossil that the latter described as a four-legged snake.Tom Saunders, University of Alberta via The Canadian Press
The dispute is not the first time Dr. Longrich and Dr. Caldwell have locked horns.
They have known each other professionally since the early 2000s, when Dr. Longrich was a PhD student at the University of Calgary.
After Dr. Longrich and others published a study in 2015 of a four-legged fossil snake that turned up in a German museum, Dr. Caldwell later travelled to Germany to study the fossil, concluding in a detailed critique published in 2021 that it was not a snake at all.
In a blog post, Dr. Longrich ascribed the criticism to professional jealousy without naming Dr. Caldwell directly.
The Xenodens debate is even more contentious because it goes beyond a disagreement over scientific interpretation and instead raises questions about whether the fossil is real.
In their statement, Dr. Longrich and his colleagues wrote that such accusations undermine efforts to “preserve Morocco’s fossil heritage for the people of Morocco and the world.”
Morocco, whose phosphate beds formed in nutrient-rich prehistoric seas, now offers many well-preserved specimens, such as these Devonian ammonites on sale in Britain.Ian Nicholson/PA Images via Reuters Connect
There’s no question that Morocco’s paleobiological bounty has yielded many important finds over the past century and spurred a growing fossil trade. In 2005, the Moroccan government estimated that at least 50,000 people were involved in the industry, which some observers valued in the tens of millions of dollars each year. More recently, the government has moved to place tighter controls on the trade. An anti-smuggling decree went into force in 2020.
But interest in the region’s treasures has also created an incentive for fossil fakery. A specimen that has been doctored to look more desirable may fetch a higher price while escaping scrutiny from private collectors. Even experts can sometimes be fooled.
“The demand for high-quality fossils often leads to both minor repairs and extensive fabrications,” said Nasrrddine Youbi, a professor of geology and paleontology at Morocco’s Cadi Ayyad University who was not involved in the mosasaur find.
The Xenodens fossil is now catalogued as part of the collection of the Natural History Museum of Marrakech. (One of Dr. Longrich’s co-authors is affiliated with the museum.)
In an e-mail, Mohamed Ghamizi, the museum’s director, took issue with the Alberta group’s suspicions.
“How can one assess the status and condition of a fossil without even examining it?” he wrote, adding that the assertions of forgery “border on defamation.”
Marrakesh is home to the museum that will one day preserve the fossil for posterity, once the controversy about its provenance has been sorted out.Ilan Rosenberg/Reuters
But others say the Albertans have a case to make.
Takuya Konishi, a mosasaur expert at the University of Cincinnati who reviewed the Alberta group’s critique, said that Dr. Longrich and his colleagues may have been too bold in asserting that Xenodens is a new genus despite its unusual appearance.
“Being weird doesn’t mean being real,” Dr. Konishi said.
He noted that many details about the find are unpersuasive to those who specialize in reptilian dentition. To become more widely accepted, he said, the discovery still needs “a lot of backing data to go against everybody who studies teeth.”
Maria Rose Petrizzo, editor-in-chief of Cretaceous Research, which published the original Xenodens discovery paper, said there were no ethical issues related to how Dr. Longrich’s paper was reviewed and handled by editors and that it was not up to the journal to resolve such disputes.
“What we need at this point is a third publication that says who is correct, because we have just two different points of view,” she said.
Debate over Xenodens has now spread to include other specimens claimed to belong to the same species, included fossils described in this poster presented earlier this spring at a meeting of the Alberta Paleontological Society.Instagram (@alberta_palaeo_society)
An extra twist in the story is the revelation by Dr. Longrich and his co-authors that additional examples of Xenodens have been discovered, with the suggestion that these may vindicate the original find.
In March, photos of additional specimens described as belonging to Xenodens were presented in a research poster at the annual meeting of the Alberta Paleontological Society in Calgary.
Dr. Caldwell said he was unimpressed by the poster and noted that the photos do not appear to show the two-tooth-per-socket pattern claimed in the original find.
In their paper questioning Xenodens, the Alberta researchers said that the original fossil examined by Dr. Longrich, which is considered the type specimen, should undergo a computed tomography (CT) scan. In principle, this form of X-ray imaging should be able to reveal whether there are any fabricated portions in the fossil jaw.
Ilaria Paparella, a curator of fossil marine reptiles at Alberta’s Royal Tyrrell Museum, said a CT scan could provide some much-needed clarity on the matter.
“X-ray and CT scanning is always a great idea. You realize that some of the bones that look real were replicated or reproduced,” she said.
In their initial statement, Dr. Longrich and his colleagues said they would conduct a CT scan to address the issues raised by the Alberta group and to provide “further scientific insight into the fossil.”
The National Museum of Natural History in Paris has equipment and resources that could help settle the dispute over the Morocco fossil.GEOFFROY VAN DER HASSELT/AFP via Getty Images
Dr. Ghamizi said that the Xenodens fossil will head from the University of Bath to the National Museum of Natural History in Paris for a CT scan scheduled some time in June. After that, he said, the fossil will be transferred to the Marrakech museum for preservation.
Earlier this month, Dr. Longrich told The Globe and Mail that scanning would be conducted on two fossils – the original type specimen and a second unpublished find that also belongs to the museum in Marrakech.
“I personally prepared both specimens in the Marrakech collection, so I’m 100-per-cent confident they’re real,” Dr. Longrich said.
Mr. Sharpe said that if Dr. Longrich and his colleagues can provide convincing evidence that Xenodens is real, it will have been a valuable exercise that sets a precedent for similar fossils to be CT-scanned.
On the other hand, Dr. Caldwell said, if the fossil is found to have been doctored, then the name Xenodens calminechari should be retired and not used again.
“If Xenodens comes up and is resurrected again, you’ll find me banging a gong and demanding to see the type specimen,” he said.