Paleontologists have discovered a remarkable fossilized jawbone in a dried riverbed in Brazil, belonging to a previously unknown species named Tanyka amnicola, which lived approximately 275 million years ago. The name Tanyka derives from the Indigenous Guaraní language, meaning 'jaw,' while amnicola translates to 'living by the river.' This ancient creature exhibits a unique twisted jaw structure, with some teeth pointing outward, indicating it may have been one of the earliest plant-eating vertebrates. The discovery was made in the Pedra de Fogo Formation, a significant site for understanding the fauna of the early Permian Period when Brazil was part of the supercontinent Gondwana. Researchers believe that Tanyka's jaw structure allowed it to grind plant material, suggesting a herbivorous diet, which is surprising as most stem tetrapods are thought to have been carnivorous. The findings contribute to a better understanding of the biodiversity and ecological dynamics of ancient ecosystems, filling gaps in our knowledge of early vertebrate evolution.