Fossil Teeth Bolster Notion That Spinosaurus Was a ‘River Monster’

A selection of some 1,200 teeth found in ancient riverbeds was dominated by Spinosaurus, suggesting they made their home in the water

Artist's interpretation of a toothy Spinosaurus.
Artist's interpretation of a toothy Spinosaurus. Davide Bonadonna / UNIVERSITY OF PORTSMOUTH

Catapulted into dino-fame by its inclusion in the Jurassic Park franchise, Spinosaurus was a fearsome, 50-foot-long predator that lived some 95 million years ago. But despite its newfound notoriety, Spinosaurus is not an easy creature to categorize. Since its discovery in Egypt in 1910, the dinosaur’s strange combination of features—from its elongated, crocodilian snout to the six-foot sail jutting out of its back—have led to rampant speculation about its lifestyle. Paleontologists and the public wanted to know: Was this extinct celebrity more at home in the water or on land?

Now, researchers think they’ve finally proven that Spinosaurus was a consummate freshwater predator. New research, published this week in the journal Cretaceous Research, details a trove of more than 1,200 dinosaur teeth discovered in ancient riverbeds in Morocco. Spinosaurus’ cone-shaped teeth accounted for nearly half of the dentition that drifted to the bottom of these ancient rivers nearly 100 million years ago, reports Michael Greshko for National Geographic.

"The enhanced abundance of Spinosaurus teeth, relative to other dinosaurs, is a reflection of their aquatic lifestyle,” says David Martill, a paleontologist at the University of Portsmouth, in a statement.

Martill explains that the presence of so many Spinosaurus teeth in the sediments of the Kem Kem river system that once flowed through what is now the Sahara Desert suggests the huge dinosaurs spent much of their lives in the water.

"From this research we are able to confirm this location as the place where this gigantic dinosaur not only lived but also died. The results are fully consistent with the idea of a truly water-dwelling, ‘river monster,’” says Martill in the statement.

The new findings strengthen prior research that also pointed to Spinosaurus being adept in the water. Earlier this year another paper described paddle-like bones from Spinosaurus’ tail, arguing that they were clear signs that the gargantuan predator was well-adapted to swimming, according to BBC News.

“When you study the bones, it’s very difficult to understand how these animals were actually interacting with their ecosystem,” Matteo Fabbri, a paleontologist at Yale University who wasn’t involved in the new study, tells National Geographic. “This study is important because it’s looking at the ecosystem itself.”

Back in 1944, as Katherin Wu reported for Smithsonian magazine in April, the study of Spinosaurus experienced a major setback when the only known partial skeleton was destroyed in a bombing raid that blew up Munich’s Paleontological Museum. As the many years of debate can attest, it’s taken decades for paleontologists to put the pieces of this massive animal’s prehistoric life back together.

Per National Geographic, the preponderance of teeth in the Kem Kem riverbed sediments could also be explained by Spinosaurus having adopted a wading approach to snagging fish at the water’s edge. But, the researchers note in their paper that the rest of the creature’s anatomy would have made this an exceedingly awkward proposition, suggesting to them that Spinosaurus swam for its dinner.

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