A prehistoric piranha-like species might have been the first flesh-eating ray-finned bony fish, as scientists believe the creature used its sharp teeth to feast on the fins of other fish that also existed around 152 million years ago, during the Jurassic Era.
According to Live Science, the fish fossil was originally discovered in 2016 in limestone deposits in the southern part of Germany. The creature was then given the name Piranhamesodon pinnatomus, with the first part of the name referring to its piranha-like teeth and behavior, and the second part describing its tendency to feed on fish fins. As documented in a study published Thursday in the journal Current Biology, this represented the first documented evidence that bony fish actually ripped chunks of flesh from their prey before eating it, much like prehistoric, cartilaginous sharks were already doing around the same time.
“At that time, the area which now is southern Germany was occupied by a shallow tropical sea dotted with small sun-bathed islands, covered by a probably sparse vegetation of ferns and cycads on which exotic animals lived: numerous insects, lizards, small dinosaurs, and the early bird Archaeopteryx,” said study co-author Martina Kolbl-Ebert, a scientist from Germany’s Jura Museum, in an interview with Gizmodo.
“In the sea, there were sponge reefs as well as small coral reefs. There were numerous invertebrate species such as ammonites, squids, or crustaceans, but also many different fish and marine reptiles.”
Together with fellow researcher and co-author David Bellwood from James Cook University in Australia, Kolbl-Ebert studied the fossil with a microscope, later conducting CT-scans to analyze the makeup of its mouth and back. The researchers also compared the prehistoric bony fish’s muscle length, jaw lever, and other metrics against those of piranhas and other modern-day fish. This painted the picture of a slow, but “highly maneuverable” fish that had serrated, triangular teeth that allowed it to easily cut into flesh.
As P. pinnatomus had a very “inconspicuous” appearance as it hung out in coral reefs and blended in with other coral fish, Kolbl-Ebert told Gizmodo that the creature might have been very effective in stalking its shell and sea urchin-eating prey.
— Gizmodo (@Gizmodo) October 18, 2018
Despite the discovery that P. pinnatomus shared a lot of similarities with modern-day piranhas, Gizmodo pointed out that both species actually aren’t related to each other, making this an example of convergent evolution, or the independent evolution of similar traits or features in unrelated species. Kolbl-Ebert described this as a rather peculiar example of the phenomenon, as P. pinnatomus dated back to the Jurassic Era, well before modern piranhas first appeared.
According to Kolbl-Ebert, P. pinnatomus is part of the pycnodontid family, a group of fish whose grasping front teeth and “button-like” rows of teeth in the back were ideal for crushing ancient snails, sea urchins, and other similar creatures. She added, however, that P. pinnatomus was different from its relatives because it had “daggers and scissors” in its mouth, making it akin to the proverbial wolf in sheep’s clothing.
Another key difference between P. pinnatomus and modern piranhas was the discovery that the former species existed in saltwater, as opposed to the latter, which can be found in freshwater. Bellwood told Gizmodo that this made the piranha-like creature even more unusual, beyond its likely status as the first bony fish that fed on other fishes.