By Basant El-Faramawy
Scientists have uncovered the fossil of Gerrothorax maritimus, the first amphibian known to have lived in a fully marine environment, according to a study published in Nature Ecology & Evolution.
Triassic predator with bony armour
The armoured animal, roughly the size of a modern giant salamander, lived around 237 million years ago during the Late Triassic period. It measured almost 90 centimetres in length and had a flattened, disc-shaped body covered in bony armour.
Suction feeding on the ocean floor
Researchers suggest the creature was a bottom-dwelling suction feeder, waiting for prey and sucking it in, similar to the modern wobbegong shark. Its skull shape and bony armour support this feeding strategy.
Overcoming physiological barriers
Modern amphibians cannot inhabit fully marine environments due to permeable skin that makes salt regulation difficult. The study proposes that Gerrothorax maritimus overcame this through its armour, which reduced water absorption through the skin, and possible gill adaptations for salt excretion.
Evidence from deep-sea sediments
Two nearly complete skeletons were found in deep-sea sediments with fingers and limbs preserved, indicating the animals died near where they lived. Geochemical analysis of strontium isotopes matched Late Triassic ocean signatures, confirming a marine habitat.
