Ancient amphibian fossil found living its whole life in sea
Scientists in China report a fossilized amphibian species that spent its entire existence living within the salty ocean waters.
Geologist Lipin Diao and team present new findings about Gerrothorax maritimus in the journal Nature Ecology & Evolution recently. Two fossils were unearthed by local people in Guanling County within a rock layer about 237 million years old.
The site was completely submerged by seas during the Late Triassic period alongside ichthyosaurs, crinoids, and turtles in that ancient marine ecosystem. Both specimens were found more than 30 kilometers from any possible nearby islands suggesting they never left the water.
Unlike modern amphibians, Gerrothorax possessed a flat body covered in plates of hard armor which prevented water absorption through the skin. Researchers believe the body armor mandated drinking water and absorbing fluids from the gut unlike in most living amphibian species today.
Further analysis of strontium isotopes in their bones offered strong evidence of their marine lifestyle by matching Triassic seawater values. The more complete specimen measures at least 73.7 centimeters along its preserved midline though some tail bones are missing now.