The fish that ate fins
During the time of the dinosaurs, there were fish with sharp teeth that hunted prey by nibbling on just their fins.
About 150 million years ago, during the Jurassic era, a bony fish species lived in the seas. It had teeth similar to the piranha, designed to slice through flesh.
However, unlike the piranha, this fish preferred to nibble on just the fins, rather than the flesh, of its prey. Researchers had come to this conclusion after studying its well-preserved remains—as well as that of its battle-scarred prey—which had been found in 2016 in limestone deposits in the quarry of Ettling in the Solnhofen region, in South Germany.
A recent paper in the Current Biology journal describes the species.
"We have other fish from the same locality with chunks missing from their fins," said co-author David Bellwood of James Cook University, Australia. "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."
Named Piranhamesodon pinnatomus (meaning "fin cutter"), it had long, pointed teeth on the exterior of the vomer (a bone forming the roof of the mouth), and at the front of the upper and lower jaws. The fossil also had triangular teeth with serrated cutting edges on the prearticular bones, along the side of the lower jaw. In all, according to the press release, "the tooth pattern and shape, jaw morphology and mechanics suggest a mouth equipped to slice flesh or fins."
Which meant that this species appeared to have evolved before its time—bony fishes were not known to bite the flesh off their prey at that time.
As lead author Martina Kölbl-Ebert, a vertebrate paleontologist and director of the Jura Museum said, "Fish as we know them, bony fishes, just did not bite flesh of other fishes at that time. Sharks have been able to bite out chunks of flesh but throughout history bony fishes have either fed on invertebrates or largely swallowed their prey whole. Biting chunks of flesh or fins was something that came much later."
Today, the fossil is part of the collection in the Jura Museum in Eichstätt, Germany.