A prehistoric herbivore with a twisted jaw and sideways-facing teeth

(Kopie 14)

An international team of palaeontologists, including researchers from the Museum für Naturkunde Berlin, has discovered a new species of early terrestrial vertebrate from Brazil: Tanyka amnicola. This amphibian lived around 275 million years ago and is characterised by a unique, twisted jaw with laterally oriented teeth, suggesting a herbivorous lifestyle. The findings have been published in the journal Proceedings of the Royal Society B.

Nine isolated lower jaws, each around 15 centimetres long, were found. “For 15 years, as part of an international collaboration with researchers from Brazil, Argentina, South Africa, the USA, the UK and Germany, we have been investigating the previously little-known fossil fauna and flora of the Parnaíba Basin in north-eastern Brazil. I was fortunate enough to find the first jaw of this new land vertebrate during one of our earliest expeditions to this region,” said Prof. Jörg Fröbisch of the Museum für Naturkunde Berlin. “What is particularly fascinating is that even during its lifetime, some 275 million years ago, it could have been described as a living fossil, as it belongs to an archaic group that actually lived 30–50 million years earlier.” Other skeletal parts have not yet been definitively identified. Nevertheless, the jawbones from the Pedra de Fogo Formation in Brazil provide important clues about the animal’s species and way of life. The name ‘Tanyka’ comes from the indigenous Guaraní language and means ‘jaw’, whilst ‘amnicola’ refers to its habitat along rivers and lakes.

Tanyka belongs to the early representatives of the tetrapods (four-legged animals), which also include the amphibians, reptiles, birds and mammals living today. “The twisted jaws seemed unusual to us for a long time, but all specimens show the same pattern – it is an anatomical feature, not a deformation,” explains Dr Jason Pardo, lead author of the study.

The teeth point outwards at the sides, whilst the inside of the jaw is directed upwards towards the palate. The surface is covered with small teeth that act like a grating surface. The researchers suspect that the teeth rubbed against each other when the mouth closed, enabling plant matter, for example, to be ground down.

“Based on the tooth structure, we assume that Tanyka ate plants, at least occasionally,” says Prof. Juan Cisneros of the Federal University of Piauí in Teresina, Brazil. “This is surprising, as most of its relatives were carnivores.”

Insight into Gondwana’s wildlife

275 million years ago, what is now Brazil was part of the southern continent of Gondwana, which encompassed large parts of South America, Africa, Australia and Antarctica. Fossils from this period are rare, so Tanyka provides new insights into the structure and interactions of animal communities during this era.

“The Pedra de Fogo Formation offers one of the few windows into the wildlife of Gondwana during the Early Permian. Tanyka shows us which animals lived there and what ecological roles they played,” explains Dr Kenneth Angielczyk, co-author of the study.

Tanyka may have been up to one metre long and lived in lakes or near rivers. Further finds, particularly skulls or intact skeletal parts, could help to fully reconstruct the animal’s physique and way of life.

Publication: J. D. Pardo, C. A. Marsicano, R. M. H. Smith, J. C. Cisneros, K. D. Angielczyk, J. Fröbisch, C. F. Kammerer, and M. Richter (2026) An aberrant stem tetrapod from the early Permian of Brazil. Proceedings of the Royal Society B: Biological sciences. DOI: 10.1098/rspb.2025.2106