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Massive 72-Million-Year-Old “Saw-Toothed” Mosasaur Fossil Sparks Debate Over Authenticity

Fossil of Mosasaurs marine reptile.
Fossil of Mosasaurs marine reptile. Image by Roland Tanglao from Vancouver, Canada, CC BY 2.0 https://creativecommons.org/licenses/by/2.0, via Wikimedia Commons

In the dynamic world of paleontology, discoveries often rewrite what we know about ancient life. However, not every fossil fits neatly into the puzzle of history. A 2021 study describing a new species of mosasaur, Xenodens calminechari, touted as a “saw-toothed sea monster,” has now come under scrutiny. Scientists are questioning the authenticity of this fossil, suspecting it may have been forged. This article delves into the mystery surrounding Xenodens, the implications of its potentially fraudulent origins, and what this means for the scientific community.

A Sea Monster Unearthed in Morocco

Massive 72-Million-Year-Old "Saw-Toothed" Mosasaur Fossil Sparks Debate Over Authenticity
An illustration of Xenodens calminechari, a mosasaur whose description was based on fossils that scientists now think might be fake. (Image credit: Henry Sharpe)

The Xenodens calminechari fossil was discovered in a phosphate mine in Khouribga, Morocco, an area renowned for its rich fossil deposits. The creature was described as having compact, blade-like teeth forming a saw-like cutting edge—features said to be unique among tetrapods. This garnered significant attention, positioning Xenodens as a marvel of marine reptilian evolution.

Unraveling the Mystery: How the Doubts Arose

Mosasaurus
Mosasaurus. Image via Depositphotos

Questions emerged when researchers revisited the fossil’s anatomy. The new study, published in The Anatomical Record, highlights discrepancies in the jaw and teeth structure. Unlike all other known mosasaurs, Xenodens appears to have two teeth in a single socket, contradicting the well-documented pattern of mosasaur dentition.

The Science Behind Mosasaur Teeth

Left maxilla of the mosasaurid Xenodens calminechari, late Maastrichtian of Sidi Chennane, Morocco by Nicholas R. Longrich.

Mosasaur teeth are individually anchored in their own sockets, supported by bone tissue that regenerates with each replacement tooth. This evolutionary adaptation ensures that their teeth remain firmly rooted throughout their predatory lives. The presence of two teeth in one socket is inconsistent with this biological mechanism, raising significant red flags.

The Role of CT Scans in Authenticating Fossils

Discovery of the first Mosasaur (Mosasaurus hoffmani), at Maastricht, engraving by G. R. Levillaire, published in the book Histoire naturelle de la montagne de Saint-Pierre de Maestricht, by Barthélemy Faujas de Saint-Fond on Google books, page 37. By G. R. Levillaire – https://www.biodiversitylibrary.org/item/280833#page/45/mode/1up, Public Domain, https://commons.wikimedia.org/w/index.php?curid=5143711

To confirm whether the fossil is genuine, scientists are calling for computed tomography (CT) scans. This non-invasive technology allows researchers to peer inside fossils, identifying different materials and assessing structural integrity. Without such scans, the authenticity of Xenodens remains in question.

Fossil Forgeries: A Known Issue in Moroccan Mines

Skull based on reconstruction from Street and Caldwell (2017). The number of vertebrae based on photos of almost complete skeleton of Mosasaurus missouriensis (TMP 2012.010.0001) which gives a rather conservative size estimate – around 14 meters along a curve with a scale up to CCMGE 10/2469 with 171 cm lower jaw. By SaltieCroc – Own work, CC BY-SA 4.0, https://commons.wikimedia.org/w/index.php?curid=79914281

Morocco’s phosphate mines are a hotspot for fossil discoveries, but they are also notorious for forgeries. In some cases, fossils are altered or assembled from unrelated specimens to make them appear more valuable or unique. The new study argues that Xenodens may be a product of this practice.

Ethical Dilemmas in Paleontology

fossils
Bones being uncovered. Image by xolo_dan via Depositphotos

The controversy extends beyond scientific scrutiny to ethical concerns. Researchers involved in the 2021 study have been criticized for withholding information about the holotype—the primary fossil used to describe a new species. Such behavior undermines scientific transparency and raises questions about research practices.

What Makes Xenodens Unique—If It’s Real?

The Hatching of a baby Mosasaur during the Cretaceous Period 2. By Francisco Hueichaleo – Own work, CC BY-SA 4.0, https://commons.wikimedia.org/w/index.php?curid=91279446

If proven genuine, Xenodens would represent a remarkable evolutionary adaptation. Its “saw-like” teeth suggest a diet that included tough, abrasive prey, such as armored fish or crustaceans. However, this uniqueness is precisely what makes the fossil’s authenticity so crucial to verify.

International Collaboration: A Solution to Forgery Issues

Handshake Photo by Ketut Subiyanto via Pexels.

Experts argue that better collaboration between local and international scientists is essential to combat fossil forgery. Moroccan paleontologist Wahiba Bel Haouz emphasizes the need for stronger fossil protection laws and ethical practices to preserve the country’s fossil heritage.

Lessons from Xenodens for the Scientific Community

A life reconstruction of Mosasaurus feeding on a juvenile abelisaurid. Sources: Environment per Wan der Ham et al. (2007)[1] Body plan of Mosasaurus is consistent with Lingham-Soliar (1995),[2] Lindgren et al. (2013),[3] and Fanti et al. (2014).[4]

The controversy surrounding Xenodens highlights the importance of rigorous peer review and verification processes in paleontology. As technology advances, tools like CT scans can help prevent similar disputes and ensure that new discoveries are legitimate.

Why Fossil Forgeries Matter

dinosaur
Ichthyosaur fossils on display. Image by jarino via Depositphotos

Fossil forgeries can mislead scientific research, skewing our understanding of evolutionary history. They also devalue genuine fossils, making it harder for researchers to secure funding and public trust.

The Broader Impact of Fossil Discoveries

Scientist pick up trilobite fossil find from ground.
Scientist pick up trilobite fossil find from ground. Image via Depositphotos

Beyond academia, fossil discoveries shape public interest and education in natural history. Misrepresented fossils like Xenodens can harm the credibility of science and dampen enthusiasm for paleontology.

What’s Next for Xenodens?

Micro computed tomograph (micro CT) of Mosasaur tooth embedded in limestone from Morocco approximately 4 cm in length. Mosasaurs were large marine reptiles that lived 101 – 66 million years ago. By ValeoXiXi – Own work, CC BY 4.0, https://commons.wikimedia.org/w/index.php?curid=84506112

The fate of Xenodens calminechari hinges on further analysis, particularly CT scans. Whether a genuine marvel or an elaborate forgery, the case of Xenodens underscores the need for integrity and collaboration in uncovering Earth’s ancient past.

The Bigger Picture in Paleontology

Example of what it might look like to unearth a fossil.
Example of what it might look like to unearth a fossil. Image by marishka-1982ok@yandex.ru via Depositphotos.

While the Xenodens controversy captures headlines, it is a reminder of the meticulous work required in paleontology. Each fossil offers a glimpse into the ancient world, but only through rigorous science can we piece together a reliable narrative of Earth’s history.