New Sea Monster Species Identified From 70-Million-Year-Old Skull Fossil in Mexico
A skull unearthed more than two decades ago in northeastern Mexico now has a name — and it belongs to a creature that once dominated the waters of the region.
Paleontologists from the Desert Museum in Saltillo and the University of Bath in England have officially identified Prognathodon cipactli as a new species of mosasaur, an aquatic reptile that stretched approximately 6 meters long and lived about 70 million years ago during the Late Cretaceous period.
The find expands the known diversity of prehistoric reptiles in Mexico and suggests that biodiversity at the end of the Cretaceous was greater than previously understood.
Where Did Scientists Find the Skull of the Sea Monster?
The nearly complete skull was found in 2001 in the Méndez Formation in Nuevo León, a state in northeastern Mexico. Researchers initially analyzed it in 2007 as an unidentified mosasaur species.
It took years of additional study before paleontologists officially classified it as something entirely new.
The findings were published in the journal Neues Jahrbuch für Geologie und Paläontologie on March 9.
The fossil site sits dozens of kilometers from the modern Gulf of Mexico. But 70 million years ago, the landscape looked nothing like it does today.
The area was a world of swamps, shallow beaches and tropical vegetation. Sedimentary seabed rocks rose to the surface over millions of years due to tectonic activity, which is why marine fossils turn up so far inland.
Northeastern Mexico, particularly the states of Coahuila and Nuevo León, is now home to dozens of fossil sites.
What Made This Sea Monster Such a Fearsome Predator?
“It was a mosasaur with short jaws, with conical and very robust teeth, allowing it to attack large prey,” Héctor Rivera-Sylva, a paleontologist at the Desert Museum and one of the study’s authors, said in an interview with Spanish newspaper El País.
That jaw structure set it apart from other mosasaurs, which tended to have slender teeth and elongated skulls. Prognathodon cipactli was built differently — stockier, more powerful.
“What we see is that it was an active hunter, which tells us a lot about how we can compare it, for example, to modern-day orcas,” he added.
Its prey included other marine reptiles, large fish and shelled animals. It likely hunted in open ocean but also near coastlines.
“At that time and in this region, it was the top predator; that was its place in the food chain. There was none bigger or more dangerous than it,” he said of the sea monster.
Prognathodon cipactli shared its era with dinosaurs but was not related to them. It went extinct in the same mass extinction event that wiped out the dinosaurs.
Why Does This Sea Monster Matter for Paleontology in Mexico?
The identification of Prognathodon cipactli positions Mexico as more than a “transitional area.” The country has its own unique species and evidence of speciation, according to the study’s findings.
For Rivera-Sylva, the find carries personal weight.
“When I was a child, we had the idea that dinosaurs hadn’t inhabited Mexico; this whole area was a big question mark. We thought it was something very distant, only in the United States or other parts of the world, but no: they’re here in Mexico too,” he said.
That shift has fueled growing interest in paleontology across Mexico, particularly among young people.
“Now I have kids who are nine, 10, or 12 years old who contact me with great interest, and I tell them, ‘If you want to see Mexican dinosaurs, you can come to the Desert Museum because Mexican dinosaurs are on display here,’” he added.
This article was created by content specialists using various tools, including AI.
