Ancient Flesh-Eating Piranha-Like Fish That Lived Alongside Dinosaurs Discovered

ancient piranha
Image showing the fossil of the piranha-like fish from Jurassic seas. M. Ebert and T. Nohl

An ancient flesh-eating fish that was remarkably similar to modern day piranhas has been discovered. Piranhamesodon pinnatomus lived around 150 million years ago—alongside the dinosaurs—and it survived by feeding on other fish, tearing chunks of flesh and fin from their bodies with their tiny razor sharp teeth.

Scientists discovered the fossil of P. pinnatomus in limestone deposits in South Germany. These deposits are extremely rich in fossilized remains. As well as the new flesh-eating fish, it is also home to many other long lost species including Archaeopteryx—a famous transitional fossil that sat somewhere between dinosaurs and modern birds on the evolutionary tree.

In a study published in Current Biology, researchers led by Martina Kölbl-Ebert of Germany's Jura-Museum Eichstätt describe P. pinnatomus. The boney creature measured just seven to nine centimeters in length—Kölbl-Ebert told Newsweek that while it appears the specimen they found was "smallish," it only would have grown slightly larger.

Analysis of the fossil revealed it had a number of specialized features that made it adept at cutting through flesh—including piranha-like teeth. These pointed teeth were found at at the front of the upper and lower jaws as well as coming from the bone of the roof of its mouth. It also had serrated triangular-shaped teeth along the sides of the lower jaw.

Alongside the fossil of P. pinnatomus, researchers also found the fossils of what appear to be the Jurassic fish's dinner. "We have other fish from the same locality with chunks missing from their fins," study author David Bellwood, James Cook University, Australia, said in a statement. "This is an amazing parallel with modern piranhas, which feed predominantly not on flesh but the fins of other fishes. It's a remarkably smart move as fins regrow, a neat renewable resource. Feed on a fish and it is dead; nibble its fins and you have food for the future."

The fish is believed to be the first of its kind—flesh-eating fish only really emerged much later in the fossil record.

P. pinnatomus is not an ancestor of modern piranhas, however. Instead, it appears to be a "remarkable" case of convergent evolution—where different species develop similar traits because they live in similar conditions. "The Pycnodontiforms are a completely different, extinct fish group," Kölbl-Ebert said. "The most obvious difference is the vertebrae column: In Piranhas it is fully ossified like in all modern teleosts. This is the fish group that dominates today, encompassing some 96 percent of all fish at present."

This illustration shows an artist's reconstruction of the head of the piranha-like fish. The Jura-Museum, Eischstatt, Germany

She also said that unlike piranahs, P. pinnatomus probably did not live in large shoals—only one specimen was found among hundreds of fish. As well as actively hunting, she also said it is possible the ancient fish was a scavenger. "It might have also fed from dead bodies, but these are rare in reef environments and for this mode of [living], the dentitions seems overkill."

The researchers now plan to learn more about how P. pinnatomus fit into the fossil site as well as describing other similar fish from the region. "When dinosaurs were walking the earth and small dinosaurs were trying to fly with the pterosaurs, fish were swimming around their feet tearing the fins or flesh off each other," Bellwood said.

Dean Lomax, a paleontologist from the U.K.'s University of Manchester, who was not involved in the research, said the discovery was interesting. "As the oldest known flesh-eating piranha-like fish, this study shows when this type of feeding behaviour may well have evolved and thus demonstrates how Piranhamesodon filled a particular role in the food chain," he told Newsweek. "It is very interesting that the study has also identified potential victims of Piranhamesodon, which, if indeed correct, provides a fascinating glimpse into predator-prey interactions during the Late Jurassic."