Two exceptional fossil skeletons discovered in China have revealed an ancient, heavily armored amphibian that lived entirely in the open ocean approximately 237 million years ago.
The fossils were found within China’s Guizhou Province, inside a zone previously covered by an old sea situated hundreds of miles away from any large landmass, according to Sciencedaily. Researchers identified the creature as Gerrothorax maritimus after examining two nearly complete skeletons preserved in rocks from the Late Triassic Period, which spanned roughly 237 million to 201 million years ago.
Thanks to the exceptional preservation of both skeletons, scientists managed to reconstruct the animal’s physical form and gain deeper insight into its lifestyle. Their findings were published October 26 in Nature Ecology & Evolution. The research received funding from the National Natural Science Foundation of China.
A China-US team has discovered fossils of Gerrothorax maritimus, a new amphibian species from about 237 million years ago—the only known amphibian in Earth’s history able to live entirely in the sea, according to the researchers. 🌊 pic.twitter.com/JtdIqfXGlI
This area is part of an ecosystem that we’ve been looking at and trying to reconstruct,
Ryosuke Motani, study corresponding author and paleobiologist at the University of California, Davis
We’ve been mostly studying marine reptiles and the fish from this place, but now we also have this amphibian, and it’s a sort of very unusual member of the lineage,
Motani added. “Amphibians were always the problem because they did not really follow the rule,” Motani says.
Reaching approximately 70 centimeters in length—comparable to a skateboard—every specimen was covered in protective bony plates. Measuring roughly the same size as a giant salamander, this strange creature featured a wide, flattened shape shielded by bony armor. Its proportions differed significantly from modern salamanders. If you think about today’s amphibians, this animal is unusual because it’s big,
Motani noted.
The first fully marine living species of stem amphibian, Gerrothorax maritimus, has been discovered, based on two nearly complete skeletons measuring at least 737 millimeters from the Late Triassic (about 237 million years ago) unearthed in southwest China's Guizhou Province,… pic.twitter.com/FBE2FhHJkR
Researchers have uncovered signs suggesting that a flat-bodied prehistoric amphibian featuring upward-facing eyes may have prowled the ocean floor to surprise unsuspecting prey.
Saltwater causes most amphibians to dry out or suffocate due to their porous skin, which facilitates oxygen uptake while simultaneously complicating the regulation of internal water and salt concentrations.
A group of international researchers has reported the first fully marine species of stem amphibian, Gerrothorax maritimus, in a recent research article published in the journal Nature Ecology & Evolution. Based on two nearly complete skeletons measuring at least 737 millimeters… pic.twitter.com/Edc3jOVJJU
The researchers also examined whether the remains might have been transported there after death, or if G. maritimus truly lived in the ocean. The specimens appeared nearly identical to their closest relatives, other amphibians that dwelled in freshwater, Motani says. But the fossils’ location was unusual, found in what was once a seabed, roughly 30 kilometers from any ancient land.
To confirm the marine lifestyle, the team performed a chemical analysis. Levels of different forms of strontium in the fossil bones matched those of the Triassic ocean. This telltale sign revealed that G. maritimus ate seafood and drank seawater. That means it lived there,
Motani says.
A group of international researchers has reported the first fully marine species of stem amphibian, Gerrothorax maritimus, in a recent research article published in the journal Nature Ecology & Evolution https://t.co/4ckNmSCnEO pic.twitter.com/ZDE5gxEw7a
Previous work by Lachlan Hart and associates had indicated that a distinct prehistoric amphibian might have traveled across the sea without necessarily inhabiting it. Because they’re amphibians, we would be looking for them in terrestrial freshwater environments,
Hart says. Perhaps there are more amphibians that have gotten their sea legs.
Earlier coverage: New 66-million-year-old amphibian species found in Spain
None of today's 8,000+ amphibian species lives only in the sea. Gerrothorax maritimus, a 74 cm armoured temnospondyl from Guizhou, China, apparently did: strontium isotopes in its bones match Late Triassic seawater, as if it grew up drinking it, far from any land of the time. https://t.co/N3jaJpVDLl
