A mosasaur species with saw-like teeth, described by scientists in 2021, may have been based on counterfeit fossils. Researchers are now urging the use of CT scans to investigate the creature’s true origin.
A never-before-seen mosasaur species, first described in 2021, may be based on forged fossils, according to a new study.
Researchers are calling for CT scans of the fossil remains to determine whether the 72.1 to 66 million-year-old jaw is genuine, after discovering several inconsistencies suggesting the fossil might be fake.
If the fossil is indeed a forgery, “it should be established in the published literature that this is a fake,” said Henry Sharpe, lead author of the study and a researcher at the University of Alberta, in an interview with Live Science. The species, Xenodens calminechari, was originally described from a partial jawbone and four sharp teeth found in a phosphate mine in Morocco’s Khouribga province. These teeth led the 2021 research team to claim the species was unique, but the new study raises doubts, particularly about the teeth. The findings were published on December 16, 2024, in The Anatomical Record.
Mosasaurs were predatory marine reptiles that dominated the oceans during the Cretaceous period (145 million to 66 million years ago). They varied greatly in size, ranging from 10 to 50 feet (3 to 15 meters), and had different tooth shapes suited to their diets. The 2021 study argued that X. calminechari had “small, short, bladelike teeth packed together to form a saw-like cutting edge,” which the team claimed was “unique among squamata” — the order to which mosasaurs belong — as well as among tetrapods, or four-limbed vertebrates.
This claim caught Sharpe’s attention, and what started as a critical review soon revealed troubling contradictions in mosasaur biology, as well as concerns about the fossil’s origin. For example, two of the mosasaur’s closely packed teeth appear to sit in a single socket, which contradicts all known mosasaur species. In mosasaurs, each tooth is typically housed in its own individual socket. “Each tooth crown makes its own house,” said study co-author Michael Caldwell, a professor of biological sciences at the University of Alberta.
Additionally, two of the teeth appear to have “medial overlap,” or material extending over them, which should not occur in normal mosasaur tooth development. “The fact that there’s that medial overlap is a huge indicator” of a possible forgery, said study co-author Mark Powers, a PhD candidate at the University of Alberta.
The fossil was not excavated by paleontologists, and the phosphate mine it was found in is known for producing fossils with forged features, according to the study.
Sharpe and his colleagues attempted to CT scan the fossil to confirm its authenticity, but when they reached out to Nick Longrich, a paleontologist at the University of Bath and lead author of the 2021 paper, they encountered difficulties. According to Sharpe, Longrich questioned whether they were writing a paper and asked, “what’s the angle of that paper?” This, Sharpe said, raised “immediate red flags.” He added that it is unethical for a scientist to withhold information or a holotype — the official specimen that represents a new species — because of disagreements over hypotheses.
Longrich did not respond to a request for comment regarding the claims in the new study.
Paleontologist Paulina Jiménez-Huidobro, from the University of Bonn, who was not involved in either study, agrees with the conclusions of the latest research, noting that the “dentition looks unusual in both morphology and implantation.” The presence of multiple teeth in a single socket suggests the teeth “do not belong to that jaw,” she told Live Science.
Wahiba Bel Haouz, a researcher at Morocco’s University of Hassan II Casablanca, who also was not involved in the research, pointed out that Morocco lacks specific legislation to protect its fossil heritage. She stressed the importance of collaboration between foreign scientists and Moroccan researchers to avoid working on forged fossils.
