The first fully sea-going amphibian has been found — 237 million years after it swam

Amphibians breathe and drink through their skin, which makes seawater a poison to them — so zoologists believed no amphibian, living or extinct, had ever been fully marine. Two nearly complete skeletons unearthed in China's Guizhou Province have just overturned that rule. Gerrothorax maritimus, described in Nature Ecology & Evolution, lived about 237 million years ago, before the dinosaurs: a flat, disc-shaped, armour-plated creature about 75 centimetres (30 inches) long, with a wide mouth built for ambushing prey by suction from the seabed. It was found in rock formed from ocean sediment, near the fossils of a 7-metre ichthyosaur — the apex predator that made all that armour a very good idea. 'The most important finding is that there was an early amphibian that lived in the sea full-time,' said co-lead author Ryosuke Motani of the University of California, Davis.