The Jura-Museum, Eischstatt, Germany

Dentes piranha e barbatanas rasgadas revelam luta antiquada

By Gretchen VogelOct. 18, 2018 , 11:00 AM

Este peixe de 150 milhões de anos (visto como uma ilustração do artista) não foi nomeado após a piranha para nada. Aparentemente, ele usou seus longos dentes em formato de adaga para cortar outros peixes, de acordo com um novo estudo, conforme evidenciado pelos barbatanas de algumas vítimas encontradas nas proximidades.

Researchers first discovered the animal—christened Piranhamesodon pinnatomus (pinnatomus means “fin cutter”)—in 2016 in the same southern German limestone deposits as the famous feathered dinosaur Archaeopteryx. Most other fish in the shallow sea where P. pinnatomus lived had teeth adapted for crushing, not biting or tearing. (Their stomach contents suggest they ate hard-shelled prey such as clams and sea urchins.)

The scientists think P. pinnatomus might have used “aggressive mimicry” the way modern-day piranhas do—even though they belong to a different branch of the fish family tree. Piranhas today resemble their more peaceable relatives, allowing them to get close enough to unsuspecting prey that they can tear off a fin. (The attack doesn’t kill the prey, and fins can regrow.)

P. pinnatomus, too, resembles other fish found nearby—except for those teeth. The fossil is the oldest bony fish known that would have been able to cut flesh out of larger prey, the team reports today in Current Biology. The researchers say it’s a striking example of evolution inventing some of the same tricks twice.

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• Plants & Animals

doi:10.1126/science.aav7748