A newly described species, Tanyka amnicola, is an ancient stem tetrapod from the early Permian of Brazil, notable for a twisted jaw and sideways-facing teeth.

The fossil, dating to about 275 million years ago, is described as an unusually odd jawbone specimen from a dry riverbed near the Amazon in Brazil, prompting initial confusion among paleontologists.

The discovery sheds light on Gondwanan ecosystems, revealing predator–prey dynamics and helping map the structure of early tetrapod communities.

The study detailing the discovery was published in the Proceedings of the Royal Society B on March 4, 2026, with authors including Jason Pardo and Ken Angielczyk from institutions like the Field Museum.

No additional dates beyond the 275-million-year timeframe are required to be included beyond what the article states.

The article places Tanyka within broader discussions of living fossils and ancient lineages that persisted into modern animal groups, drawing comparisons to platypus-like traits among early mammals historically.

Fossils imply the animal lived in lake environments and likely had aquatic tendencies during the early Permian within Gondwana.

Researchers emphasize the need for more fossil evidence to confirm the full anatomy and relationships of Tanyka beyond the isolated jaws.

Based on related species, Tanyka amnicola may have resembled a salamander with a longer snout and could have grown up to about 91 centimeters in length.

The twisted jaw is a natural anatomical feature of the species, not a deformation, a conclusion supported by multiple well-preserved jaws.

Pardo and colleagues published in the Proceedings of the Royal Society B detailing the jaw twist as genuine, supported by eight other similar fossil specimens.

The discovery highlights the unusual evolutionary path of this lineage, noting that most stem tetrapods were carnivorous while Tanyka’s denticle-equipped jaw suggests a distinctive feeding strategy.