The Discovery
Modern amphibians are known for leading a dual existence divided between land and fresh water, but a fossil discovery reveals that an ancient species lived exclusively in the ocean. In the Guizhou Province of southwestern China, researchers analyzed two largely complete fossilized skeletons recovered from deep-sea sediments. The newly classified species, named Gerrothorax maritimus, inhabited saltwater environments approximately 237 million years ago during the Triassic period.
The preserved state of the fossils indicates the creatures died close to their actual habitat, as drifting ocean carcasses usually lose limbs and dry out prior to reaching the seafloor. Additionally, the remains were uncovered alongside an ancient marine reptile known as an ichthyosaur, and testing of strontium proportions within the fossils matched the signature of Late Triassic oceans.
What Scientists Found
Anatomical examinations indicate that Gerrothorax maritimus was a flattened, bottom-dwelling creature measuring around 30 inches long that ambushed prey by sucking it in as it passed. Unlike modern amphibians, it possessed physical traits that allowed it to survive in ocean water:
- Bony Armor: A tough outer covering prevented seawater from extracting fluid from its body through osmotic pressure.
- Salt Filtering: Rather than relying on permeable skin to absorb fluids, the creature drank water through its mouth and filtered out salt using its gills.
Out of more than 8,000 living amphibian species today, none reside in marine environments, and only two percent can tolerate any salt exposure. Because normal amphibian skin allows water to pass freely, swimming in seawater dehydrates modern species. Analysis shows that the closest relative to G. maritimus was G. pulcherrimus, an extinct freshwater amphibian with similar bodily armor. This led researchers to determine that the marine lifestyle was an evolutionary accident made possible by pre-existing anatomical features.
Why It Matters
This discovery demonstrates that the ancient relationship between amphibians and marine environments is significantly more complex than scientists originally thought. Gaining insight into how prehistoric species successfully adapted to salty environments helps researchers better understand amphibian survival mechanisms, especially as modern ecosystems face environmental shifts such as rising sea levels and freshwater salinization.
Source: prehistoric animals new study - BingNews · Published October 30, 2026 · Photo by Blond Fox on Unsplash
