This New Species Resembled a Platypus But Had a ‘Weird’ Jaw That Baffled Scientists
A newly discovered 275-million-year-old species found near the Amazon rainforest in Brazil had a jaw unlike anything seen before — and it’s forcing scientists to rethink when an entire lineage of animals went extinct.
The new species is called Tanyka amnicola, a name that roughly translates to “jaw living next to the river.”
It looked something like a salamander and lived alongside the earliest ancestors of modern reptiles and mammals during the Early Permian Period.
According to a study published in the journal Proceedings of the Royal Society B, the animal’s most defining feature was a lower jaw that twisted outward from back to front, with some teeth pointing outward and sideways rather than facing the upper teeth.
The study was led by Jason Pardo, with Martha Richter as co-author.
A Fossil That Confused Its Discoverers
The story behind the identification of Tanyka amnicola is nearly as unusual as the animal itself. Researchers initially found one twisted jawbone during excavations near the Amazon rainforest.
“At first, we wondered if these fossils might be the remains of a fish,” Richter recalled, per the Natural History Museum. “It was only once the fossils were properly prepared in the lab that the true nature of Tanyka was clearly revealed to us.”
Over time, the team discovered eight more jawbones bearing the same twist — nine in total.
The repeated pattern confirmed the twisted jaw was not the result of damage or deformation. It was a natural anatomical feature built into the biology of the animal.
“It’s a really strange animal, and the weird twist in the jaw drove us crazy trying to figure it out. But nine jaws we’ve found have this twist, including the really well-preserved ones, so it’s not a deformation. It’s just the way this animal was,” Pardo added.
How the Twisted Jaw Worked
Most tetrapods — the broad group that includes four-limbed animals — have teeth that face each other in the upper and lower jaws.
This standard arrangement allows animals to slice, cut and grind food. It has persisted across hundreds of millions of years of evolution.
Tanyka’s jaw worked very differently. The lower jaw twisted outward, and the inner jaw contained small grinding teeth called denticles.
If you were to run your tongue over the teeth on your lower jaw, you would feel the tops of your teeth facing up towards the roof of your mouth.
In Tanyka, the twisted lower jaw meant the teeth were pointed out to the sides. The part of the jawbone that normally faces the tongue is pointed upwards.
Researchers believe the denticles in the upper and lower jaws likely rubbed together to grind food.
This suggests the animal may have eaten tough plant material and small invertebrates with hard shells, making Tanyka possibly omnivorous or herbivorous, unlike many of its meat-eating relatives.
Researchers described the species as belonging to a more experimental stage in early animal evolution, a period when nature was still testing out a wide variety of body plans and survival strategies.
Tanyka amnicola Was the ‘Living Fossil’ of Its Time
Tanyka amnicola belonged to a group called stem tetrapods — early relatives of modern four-limbed animals. These creatures eventually gave rise to the ancestors of amphibians, reptiles, birds and mammals.
Most stem tetrapods went extinct long before Tanyka lived. The fact that this species was still around 275 million years ago makes it an extraordinary outlier.
“Tanyka is a little like a platypus, in the sense that it was a member of the stem tetrapod lineage that remained even after newer, more modern tetrapods evolved,” Pardo said, per the NHM. “It was a living fossil in its time.”
“By comparing its anatomical traits to the characteristics of known species from across hundreds of millions of years, we found that this animal was actually a primitive tetrapod after all,” Richter added.
Scientists are uncertain about the full body shape of Tanyka because only jaw fossils have been definitively linked to the species. Researchers believe it likely resembled a salamander-like animal with a longer snout.
Other nearby fossils may belong to the same species, but this has not yet been confirmed. For now, Tanyka is known almost exclusively through its nine jaw fossils.
Rewriting the Timeline of Extinction
The discovery does more than introduce one strange animal. It forces scientists to reconsider an important chapter in Earth’s history.
During the time Tanyka lived, Earth’s land was joined into the supercontinent Pangaea. The climate in the region where the fossils were found was likely hot and seasonally dry.
Scientists long believed stem tetrapods largely disappeared after a major ecological event known as the Carboniferous Rainforest Collapse. That event caused widespread destruction of tropical forests and loss of the humid environments many early tetrapods relied on.
The discovery of Tanyka suggests some stem tetrapods survived much longer than scientists previously thought.
One possible explanation is that species in the southern part of Pangaea may have experienced different climates than those in the north, allowing them to survive after northern populations went extinct.
What Tanyka amnicola represents is a reminder of how much remains unknown about life’s long history on this planet.
The story also highlights the painstaking work of paleontology — from the initial confusion over whether a fossil belonged to a fish, to the moment a ninth matching jawbone confirmed the twist was no accident but a remarkable product of evolution.
BOTTOM LINE: Nine twisted jawbones found near the Amazon are pushing scientists to reconsider how long primitive tetrapods survived — and whether southern Pangaea served as a refuge after their relatives in the north went extinct.
Production of this article included the use of AI. It was reviewed and edited by a team of content specialists.
