A a species of mosasaur never seen before first described in 2021 could be based on forged fossils, a new study suggests.
Researchers are now calling for computed tomography (CT) scans of the remains to verify whether the 72.1- to 66-million-year-old jawbone is real after discovering a number of anomalies indicating it is a fake.
If this fossil is indeed a fake, it “should be established in the published literature that it is a fake,” said the study’s lead author. Henry Sharperesearcher at the University of Alberta, told Live Science.
The scientists behind the original study describes the species, named Xenodens calminechari, from a partial jaw bone and four sharp teeth discovered in a phosphate mine in the Moroccan province of Khouribga. These teeth prompted the team in 2021 to make claims about its uniqueness, and these are key to the doubts raised in the new study, published December 16, 2024 in the journal The anatomical file.
Mosasaurs were predatory marine reptiles that dominated the oceans during the Cretaceous Period (145 million to 66 million years ago). They were extremely diverse, reaching lengths of between 10 and 50 feet (3 to 15 meters). They also had different tooth shapes suited to their different diets. The 2021 team claimed that X. calminechari had “small, short, blade-like teeth brought together to form a saw-like cutting edge.” According to the team, this was not only “unique among squamata” – the order to which mosasaurs belong – but also among tetrapods, or four-limbed vertebrates.
This caught Sharpe’s attention. What began as an exercise in critical examination revealed troubling contradictions in mosasaur biology, coupled with concerns about the fossil’s provenance.
Two of the mosasaur’s clenched teeth are found in a tooth socket. This conflicts with all other known mosasaur species, in which each tooth has its own socket, according to the new study. Rather than being constructed from jaw bone, tooth sockets are “made from bone that grows from the tooth itself. Each dental crown is its own home,” said the co-author of the study. Michael Caldwellprofessor of biological sciences at the University of Alberta. In other words, there should only be one tooth per socket.
Mosasaurs “replaced their teeth continually throughout their lives,” he told Live Science. “Every time one of these teeth is resorbed and falls out, there’s a huge gap left. And that’s because the next tooth goes into that hole to rebuild all that tissue so it’s firmly anchored in the jawbone.”
Additionally, rather than sitting flush with the jaw, two of the teeth also appear to have a bit of material, or “medial overlap,” extending over them on one side. This overlap should not be present in normal mosasaur tooth development. “The fact that there is this medial overlap is a huge indicator” of possible counterfeiting, study co-author Mark powersdoctoral student at the University of Alberta, told Live Science.
The fossil was not excavated by paleontologists and the phosphate mine in which it was discovered came from an area known for fossils with forged features, according to the study.
Sharpe and his colleagues hoped to scan the fossil to determine if it was a fake, but they contacted Nick LongrichUniversity of Bath paleontologist and lead author of the 2021 paper, the fossil’s comments proved problematic.
According to Sharpe, Longrich asked if they were writing an article and “if so, what is the angle of this article?” That raised “immediate red flags,” Sharpe said. “It’s the holotype” — the official specimen that represents a new species. He added that scientists cannot withhold information about a holotype or the holotype itself because other researchers do not support your hypothesis. “It’s completely unethical for him to ask for this,” he added.
Longrich did not respond to a request for comment on the new study’s claims.
Paulina Jiménez-Huidobroa paleontologist from the University of Bonn who was not involved in either study, agrees with the findings of the latter paper, noting that “the dentition appears unusual both in terms of morphology and location.” Having multiple teeth in the same socket suggests “that these teeth don’t belong in this jaw,” she told Live Science.
“It’s a shame that Xenodens could not be scanned,” she added. “CT scans allow us to see internal structures and distinguish different materials based on their densities.”
Wahiba Bel Haouzresearcher at Hassan II University in Casablanca in Morocco, who was also not involved in the research, said the country does not yet have “legislation to protect and preserve our fossil heritage.” She said foreign scientists should always collaborate with Moroccans to avoid working on fakes.