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Most amphibians shrivel or suffocate in saltwater. But long ago, an oddball armored amphibian may have dwelled deep in the ocean.

Scientists have found evidence that an ancient amphibian with a flattened body and upturned eyes may have once stalked the seafloor. The animal, Gerrothorax maritimus , is the first ever amphibian known to have lived without access to land or freshwater, researchers report October 26 in Nature Ecology & Evolution.

G. maritimus , which lived 237 million years ago, was rather unlike today’s amphibians, which breathe and drink through their porous skin. The creature’s lifestyle was unimaginable for an amphibian, says Ryosuke Motani, a paleobiologist at the University of California, Davis. Of the more than 8,000 amphibians known today, none live solely in saltwater.

Motani and his colleagues inspected two well-preserved G.…