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03/04/2026 13:06

An ancient plant-eater with a twisted jaw and sideways-facing teeth

Dr. Gesine Steiner Pressestelle
Museum für Naturkunde - Leibniz-Institut für Evolutions- und Biodiversitätsforschung

    An international team of paleontologists, including researchers from the Museum für Naturkunde Berlin, has discovered a new species of early tetrapod (four-limbed vertebrate) from Brazil: Tanyka amnicola. This amphibian lived around 275 million years ago and is characterized by a unique, twisted lower jaw with sideways-facing teeth, suggesting a herbivorous lifestyle. The findings were published in the journal Proceedings of the Royal Society B.

    Nine isolated lower jaws, each about 15 centimeters long, were recovered. “For 15 years, we have been researching the previously little-known fossil fauna and flora of the Parnaíba Basin in northeastern Brazil as part of an international collaboration with researchers from Brazil, Argentina, South Africa, the USA, Great Britain, and Germany. I was fortunate to discover the first jaw of this new tetrapod during one of our earliest expeditions to this region,” says Prof. Jörg Fröbisch of the Museum für Naturkunde Berlin. "What's particularly exciting is that it could have been described as a living fossil even during its own lifetime, around 275 million years ago, since it belongs to an archaic group that actually lived 30-50 million years earlier." No additional skeletal elements can yet be confidently assigned to the species. Nevertheless, the jawbones from Brazil’s Pedra de Fogo Formation provide important insights into the animal’s anatomy and lifestyle. The name “Tanyka” comes from the Indigenous Guaraní language and means “jaw,” while “amnicola” refers to a life lived near rivers and lakes.

    Tanyka belongs to early representatives of tetrapods, 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’s an anatomical feature, not a deformation,” explains Dr. Jason Pardo, lead author of the study.

    The teeth point sideways rather than upward, and the inner surface of the jaw is oriented toward the roof of the mouth. This surface is covered with small tooth-like structures that form a rasping, grinding area. The researchers suggest that when the animal closed its mouth, the teeth would have rubbed against one another, helping for example to break down plant material.

    “Based on the tooth structure, we believe that Tanyka fed on plants at least part of the time,” says Prof. Juan Cisneros of the Federal University of Piauí in Teresina, Brazil. “This is surprising, since most of its close relatives were carnivorous.”

    Around 275 million years ago, what is now Brazil was part of the southern supercontinent Gondwana, which included much of present-day South America, Africa, Australia, and Antarctica. Fossils from this time and region are relatively rare, making Tanyka an important source of new information about the structure and interactions of ancient ecosystems.

    “The Pedra de Fogo Formation offers one of the few windows into Gondwana’s animal life during the early Permian. Tanyka helps us understand which animals lived there and the ecological roles they played,” says Dr. Kenneth Angielczyk, co-author of the study.
    Tanyka may have reached a length of up to one meter (about three feet) and likely lived in lakes or near rivers. Additional discoveries—especially a skull or articulated skeletal remains—could help researchers more fully reconstruct the animal’s body plan and way of life.


    Original 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


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    Criteria of this press release:
    Journalists
    Biology, Environment / ecology, Geosciences
    transregional, national
    Research results, Scientific Publications
    English


     

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