Ancient ‘Jaw from the River’ Reveals Evolutionary Oddity
Animals bite, grind, and grab with their teeth – but nothing used its mouth quite like Tanyka amnicola. With its uniquely twisted jaw and sideways-facing teeth, the new species was a relic of an earlier and more experimental time in the evolution of life on Earth.
A Living Fossil Unearthed in Brazil
Fossils discovered in Brazil show that an ancient group of animals survived for much longer than previously thought. Researchers digging near the Amazon rainforest discovered an unusually twisted jawbone, and subsequent finds of eight more confirmed it wasn’t damage, but a new species. The animal has been named Tanyka amnicola, meaning ‘jaw living next to the river.’
How Did Tanyka Eat?
Unlike most tetrapods where teeth in both jaws oppose each other for cutting and grinding, Tanyka’s lower jaw twists outwards, with some teeth pointing sideways. The inside of the jawbone is lined with tiny teeth, or denticles, for grinding. Researchers believe this unique arrangement allowed Tanyka to grind up plants or small invertebrates.
A Survivor from a Lost World
Most stem tetrapods, the group to which Tanyka belongs, were extinct 275 million years ago, replaced by more advanced tetrapods. However, Tanyka’s late survival is surprising. Dr. Jason Pardo, the study’s lead author, compares it to a platypus – a lineage that persisted even after more modern tetrapods evolved. He describes Tanyka as a “living fossil.”
Pangaea and the Persistence of Stem Tetrapods
During the Early Permian Period, when Tanyka lived, most landmasses were united in the supercontinent Pangaea. It was long assumed stem tetrapods died out due to the Carboniferous rainforest collapse, which caused drier habitats. However, Tanyka’s discovery suggests these animals may have survived longer in the southern part of Pangaea, potentially due to differing climates.
The area where Tanyka lived was hot and seasonally dry, suggesting it may have been better adapted to arid conditions than its northern counterparts. Further fossil discoveries from South America, Africa, Australia, and Antarctica are needed to understand why these southern species persisted.
Implications for Understanding Early Tetrapod Evolution
The discovery of Tanyka amnicola challenges previous assumptions about the extinction timeline of stem tetrapods. It suggests that these early tetrapods were more adaptable and geographically diverse than previously believed. This finding opens new avenues for research into the environmental factors that influenced their survival and eventual decline.
Frequently Asked Questions
- What is a stem tetrapod?
- Stem tetrapods are an early group of four-limbed vertebrates that represent a transitional stage in the evolution of amphibians, reptiles, birds, and mammals.
- Where was Tanyka amnicola discovered?
- Fossils of Tanyka amnicola were discovered in Brazil, near the Amazon rainforest.
- What did Tanyka amnicola likely eat?
- Researchers believe Tanyka amnicola likely ate plants or small invertebrates, grinding them up with its unique jaw and teeth.
- Why is Tanyka amnicola considered a ‘living fossil’?
- It’s considered a ‘living fossil’ because it represents a lineage of animals that was thought to have died out much earlier in evolutionary history.
Want to learn more about ancient life and evolutionary discoveries? Explore our other articles on paleontology and prehistoric creatures. Click here to browse our science section.
