Dinosaur-Era Super-Piranha Terrorized Jurassic Seas

By Charles Q. Choi, Live Science Contributor | October 18, 2018 06:36pm ET

An artist's reconstruction of the piranha-like fish, showing off its crazy ferocious teeth.

Credit: The Jura-Museum, Eischstatt, Germany

Um peixe semelhante à piranha com uma boca cheia de dentes pontudos (alguns até se projetando do céu da boca) uma vez nadou pelos mares jurássicos, rasgando carne ou até barbatanas dos corpos de outras criaturas aquáticas.

Isso foi há 152 milhões de anos, revelou um novo estudo de um fóssil da criatura encontrada na Alemanha. Naquela época, os pterodáctilos voavam nos céus e os estegossauros e brontossauros caminhavam pela Terra. Os cientistas descobriram o espécime em 2016 nos mesmos depósitos de calcário no interior do sul da Alemanha que produziam fósseis de Archaeopteryx, considerado por muito tempo a primeira ave conhecida.

Back when this fish lived, the area in which it swam "was occupied by a shallow tropical sea dotted with small, sunbathed 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," study lead author Martina Kölbl-Ebert, a vertebrate paleontologist and director of the Jura Museum in Eichstätt, Germany, told Live Science. "In the sea, there were sponge reefs as well as small coral reefs. There were numerous invertebrate species, such as crustaceans, but also many different fish and marine reptiles." [Photos: The Freakiest-Looking Fish]

After the scientists carefully freed the 2.8-inch-long (7.1 centimeters) fossil from its rocky prison with the help of scalpels, needles and a microscope, they discovered that it had long, pointed teeth in the front of both the upper and lower jaws. These teeth also appeared on the outside of the vomer, a bone forming the roof of the mouth. In addition, triangular teeth with serrated cutting edges jutted from the bones that lay along the side of the lower jaw.

The fossil of the new piranha-like fish shows its pointed teeth that probably helped it feed on the fins of other fishes in Jurassic seas.

Credit: M. Ebert and T. Nohl

The pattern and shape of the teeth and jaws suggest that this fish was equipped to slice flesh or fins in a strikingly similar manner to modern piranhas, the study said. The researchers named this fish Piranhamesodon pinnatomus, with Piranhamesodon referring to the creature's piranha-like nature and pinnatomus meaning "fin cutter."

The paleontologists also discovered fossils of fish that Piranhamesodon may have hunted; these animals had chunks of tissue missing from their fins.

"This is an amazing parallel with modern piranhas, which feed predominantly not on flesh but [on] the fins of other fishes," study co-author David Bellwood, at James Cook University in Australia, said in a statement. "It's a remarkably smart move, as fins regrow, [making them] a neat renewable resource. Feed on a fish, and it is dead; nibble its fins, and you have food for the future."

Previously, bony fish — fish whose skeletons are made of bone — were not known to bite chunks of flesh or fins from prey until a much later period on the evolutionary timeline, Kölbl-Ebert said. Instead, they were thought to either crunch on invertebrates or swallow their prey whole. (Sharks were long known to bite chunks of flesh from prey, but their skeletons are made of cartilage, not bone.)

"O novo [encontrado] peixe é um exemplo muito interessante para a evolução convergente, evoluindo para um modo de vida completamente novo", disse Kölbl-Ebert. "O peixe representa o registro mais antigo da alimentação da nadadeira em peixes ósseos." (A evolução convergente ocorre quando dois animais diferentes evoluem de maneira semelhante para resolver problemas semelhantes, como a forma como os golfinhos e antigos répteis marinhos conhecidos como ictiossauros tinham formas corporais semelhantes para ajudá-los a nadar rapidamente na água.)

Piranhamesodon pertence a um grupo de peixes chamado pycnodontídeoss. "Normalmente, todos os peixes deste grupo de peixes têm dentes na frente e dentes semelhantes a botões nas costas, adequados para esmagar caracóis marinhos, ouriços do mar ou outros organismos shelly", disse Kölbl-Ebert. "Mas este tinha adagas e tesouras na boca. Era um verdadeiro lobo em pele de carneiro."

This discovery "highlights the sheer evolutionary flexibility of fishes," Kölbl-Ebert said. "If a fish with highly specialized crushing teeth can develop highly specialized cutting teeth, what is next? It is a staggering example of evolutionary versatility and opportunism."

The fossil is now on display in the Jura Museum in Germany. The scientists detailed their findings online Oct. 18 in the journal Current Biology.

Originally published on Live Science.