Fossils in China reveal amphibian that may have been the first to live only in the sea
The 237-million-year-old Gerrothorax maritimus had bony armor and gills; none of the more than 8,000 living amphibians is fully marine.
Translated from the Portuguese original by the Panorama newsroom. Read in Portuguese
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An amphibian that lived about 237 million years ago may be the oldest record of an animal of its group to spend its entire life in the sea, without returning to dry land or fresh water. According to g1, the species, named Gerrothorax maritimus, was described in a study published on Monday (26) in the journal Nature Ecology & Evolution.
The researchers relied on two nearly complete skeletons found in Guizhou province, in southern China. The animal had a flattened body covered by a bony armor that protected it from water loss, as well as gills and a digestive system adapted to salt.
Chemical analyses of strontium in the fossils indicated a signature consistent with seawater, and the skeletons were at least 30 kilometers from the ancient islands. With a wide mouth, the creature captured prey by suction on the ocean floor.
The discovery stands out because none of the more than 8,000 living amphibian species is fully marine: frogs, toads and salamanders have highly permeable skin, an advantage in humid environments but a problem in salt water.
Details about the animal's reproduction and internal physiology remain unknown.