Newly identified Triassic amphibian shows evidence of marine adaptation
Fossils of a heavily armored amphibian from the Late Triassic in China suggest the species may have lived fully in salty seas, a rare trait among amphibians.
Researchers have described two fossils of a primitive amphibian discovered in Guizhou province, China, that date to the Late Triassic, about 237 million years ago. The specimens, provisionally named Gerrothorax maritimus, measured roughly 74 centimetres in length, possessed flattened bodies and were largely covered in bony armor, traits that could have facilitated life in the region's ancient salty sea.
"If this Triassic amphibian, Gerrothorax, really was fully marine, then it is a game-changer," said Steve Brusatte, a palaeontologist and evolutionary biologist at the University of Edinburgh. He added that the find challenges the current understanding that no modern amphibian species inhabits marine environments exclusively.
Ryosuke Motani, a palaeobiologist at the University of California, Davis and co-author of the study, noted that while some amphibians can tolerate higher salinity, they typically manage excess salt by drinking fresh water. The new species may have employed different physiological mechanisms to cope with its marine habitat.
The discovery expands knowledge of amphibian diversity during the Triassic and provides insight into how early tetrapods might have adapted to marine conditions.