A new study raised serious concerns about the authenticity of the mosasaur species Xenodens calminechari, originally described in 2021 based on fossils unearthed in a Moroccan phosphate mine. Researchers are requesting computed tomography (CT) scans of the remains to verify whether the 66 to 72.1 million-year-old jaw is genuine or a forgery, according to Live Science.
The incomplete jawbone and four sharp teeth of Xenodens calminechari were discovered in a phosphate mine in Morocco known for the circulation of forged fossils and falsified features.
"If the fossil is indeed a forgery, it should be established in the published literature as such," said Henry Sharpe, the lead author of the new study and a researcher at the University of Alberta, according to Live Science. Sharpe and his colleagues noted that two of the surviving teeth on the alleged Xenodens calminechari jaw sit within a single tooth socket, a feature that contradicts all other known species of mosasaurs, where each tooth has its own socket.
Mosasaurs were large marine lizards and one of the ocean's top predators during the Cretaceous period, reaching lengths from 3 to 15 meters. They had varying tooth shapes befitting their different diets. The 2021 study claimed that Xenodens calminechari had "small, short, blade-like teeth that were crowded together to form a cutting edge that resembled a saw," according to Live Science. This tooth structure was described as unique among squamata—the order to which mosasaurs belong—and even among all tetrapods.
Sharpe's attention was caught by the claim of uniqueness in the 2021 study, prompting him and his colleagues to take a closer look. The team found that two mosasaur teeth were found in one tooth socket in Xenodens calminechari, contradicting previous knowledge that this species has one tooth socket per tooth, consistent with all other known mosasaurs. "That's the holotype—the official specimen that represents a new species," Sharpe said, according to Live Science. He added that scientists cannot withhold information about a holotype or the holotype itself because other researchers don't support their hypothesis.
Nick Longrich, the lead author of the 2021 study, did not respond to a request for comment about the claims in the new study, Live Science reported.
Other experts also expressed doubts about the fossil's authenticity. "The dentition looks unusual in both morphology and implantation," said Paulina Jiménez-Huidobro, a paleontologist at the University of Bonn who was not involved in either study. "Having multiple teeth in one socket suggests that those teeth do not belong to that jaw," she added.
The lack of regulation in Morocco facilitates the circulation of forged fossil pieces. Wahiba Bel Haouz, a researcher at Morocco's University of Hassan II Casablanca, highlighted the lack of legislation in Morocco to protect and preserve fossil heritage, according to O Globo. She warned that foreign scientists should always collaborate with local researchers to avoid working on forgeries and fraud.
The article was written with the assistance of a news analysis system.