Ancient Animal Had Twisted Jaw for Grinding Plants

Paleontologists discovered a 275-million-year-old animal with a unique, twisted jaw structure. This creature, named *Tanyka amnicola*, likely used its specialized jaw to grind plant material. Researchers found nine jawbones in a dried riverbed in Brazil.

The jawbones measured about six inches long. The lower jaw was twisted, causing some teeth to point outward and sideways. Rows of smaller teeth, called denticles, lined the inner surface of the jaw. This arrangement created a grinding surface similar to a cheese grater.

Scientists believe this dental structure indicates *Tanyka amnicola* was an herbivore. This finding is significant because most early tetrapods, four-limbed vertebrates, were thought to be carnivorous. The species belongs to an ancient lineage of stem tetrapods, making it a "living fossil" of its time.

*Tanyka amnicola* means "jaw dweller by the river" in a combination of Guaraní and Latin. The animal likely lived in freshwater environments. Its full body shape remains unknown, but comparisons to related species suggest it may have resembled a salamander up to three feet long.

The discovery provides insight into the early Permian Period in Gondwana, a supercontinent that included present-day South America. Fossils from this region and time are relatively rare. The study was published in *Proceedings of the Royal Society B*.