Science & Tech · Science & Environment · 1 hr ago
Fossil shows an amphibian lived entirely at sea 237 million years ago
A fossil from China points to an amphibian that lived entirely at sea about 237 million years ago, during the Late Triassic.
The species, named Gerrothorax maritimus, was about 74 centimetres long and lived on the ocean floor.
Its bones carry a seawater signature, and the fossil site was at least 30 kilometres from land, supporting the conclusion that it grew up in the ocean rather than being washed there after death.
The animal had four legs and gills, and its close relative lived in fresh water.
Researchers think strong body armour may have helped it survive salt water, which is usually dangerous for amphibians because their skin lets substances pass through.
Its broad mouth and neck bone suggest it may have caught prey by suction, waiting on the seafloor to ambush it.
The find is the first evidence of a fully marine amphibian, a way of life not seen in any of the roughly 8,000 amphibian species alive today; the researchers suggest marine reptiles may have limited its chances to diversify.
A fossil from China provides evidence of the first known amphibian to live entirely in the sea.
Named Gerrothorax maritimus, the animal lived about 237 million years ago during the Late Triassic.
The roughly 74-centimetre-long creature had a flattened body covered in bony armour and likely lived on the seafloor.
Researchers used strontium isotope ratios in its bones to find a seawater signature, suggesting it grew to adulthood in the ocean.
- Who
- Gerrothorax maritimus, an extinct amphibian.
- What
- Fossils suggest it was fully adapted to life in the sea.
- When
- About 237 million years ago, during the Late Triassic.
- Where
- In what is now Guizhou Province, China.
- Why
- Its bony armour may have helped it survive in salt water; researchers suggest the armour originally protected its relatives from freshwater predators.
This story does not have two clearly opposing sides.
Gerrothorax maritimus lived in the Late Triassic seas.
Farmers found the fossil in what is now a national geopark in Guanling County, China.
Articles reported the fossil evidence for the fully marine amphibian.
- Species
- Gerrothorax maritimus
- Age
- About 237 million years
- Length
- 74 centimetres in New Scientist; roughly three feet in Popular Science
- Location
- Guanling County, Guizhou Province, China
- Environment
- Marine; the fossil bones showed a seawater isotope signature
- Researchers’ institutions
- University of California, Davis; Peking University; Geological Museum of Guizhou
3 sources
What people are saying
It was a flat animal that lived on the sea floor
This area is part of an ecosystem that we’ve been looking at and trying to reconstruct
They would probably just wait at the bottom and then when prey comes around, they would just suck it in
If not for the marine invasion by many groups of reptiles at the same time, they might have even had a chance at diversifying in this niche, but that clearly didn’t occur