In 2021, scientists identified a new species of mosasaur when a Cretaceous period jaw with unusual teeth was found in a Moroccan mine. There’s just one problem—relics may have been created.
Researchers in Canada have raised doubts about the authenticity of fossils used to identify and describe a new species of extinct marine reptile, Xenodens calminechariin 2021. Their analysis, detailed in a December 16 study published by Anatomical recordhighlights inconsistencies between previous studies and calls for new CT scans of the jaw to confirm their validity.
If their skepticism turns out to be true, “it should be confirmed in the published literature that this is false,” said Henry Sharpe of the University of Alberta, who led the latest study. Living Science.
Our objection to “Xenodens” is now published open access in The Anatomical Record: this strange “shark-toothed” mosasaur may be fake and nondiagnostic (🧵) pic.twitter.com/9s1UWMYJaw
– Hank Sharpe (@Paleoartologist) December 17, 2024
Mosasaurs were the largest marine lizards and the leading marine animals during the Cretaceous period (145.5 to 66 million years ago), with some individuals reaching 17 meters in length. The researchers of the 2021 study partly based their identification of the new mosasaur species on four sharp teeth found in an incomplete jaw, dated between 72.1 and 66 million years ago, and excavated from a Moroccan phosphate mine.
“New mosasaurid shows battery of teeth [dental arrangement] with many small, short, blade-like teeth fused together to form a saw-like cutting edge,” the researchers, led by Nicholas R. Longrich of the University of Bath, wrote in a 2021 study. They say it’s the first such arrangement of teeth found in tetrapods (four-legged vertebrates), and it’s this theory that prompted Sharpe and his colleagues to take a closer look.
Two teeth are suspected X. calminechari the jaw rests within a single tooth socket—a feature at odds with most other known mosasaur teeth and jaw arrangements, where each tooth grows out of its socket. Mosasaur tooth sockets were built from the bone of individual teeth, as opposed to the jawbone, explains Michael Caldwell of the University of Alberta, who also participated in the new study. That means each tooth must have its own socket.
“Every time one of these teeth is rebonded and falls out, there is a large cavity left. And that’s because the next tooth goes into that hole to build all that tissue back up to hold it firmly in the jaw,” he told Live Science. In addition, Sharpe’s team suggests the presence of “potential adhesions” and says that some type of tissue accumulation on top of two teeth is unusual and can indicate a fake, according to the study.
Apart from the teeth themselves, the discovery of the jawbone in the Khouribga province of Morocco occurred under potentially suspicious circumstances, as the fossils were “found unscientifically (without technical supervision) in a Moroccan area that produces many modified or reconstructed specimens,” the study wrote.
The researchers eventually suggested that the teeth and jaw may belong to two different creatures, although CT scans of the remains could resolve any doubts. It remains to be seen whether researchers will be able to apply this method to X. calminechari fossils—or convincing others to do so—in the near future. In the meantime, proceed with caution when you come across quotes of a new mosasaur with unusual teeth!
