Newly Named Fossil Salamander, an Ancient Cousin of the Axolotl, Surfaces in Mexico

Paleontologists have described a new species of fossil salamander from central Mexico, an ancient relative of the famous axolotl that lived millions of years before the modern, perpetually youthful amphibian became a scientific and cultural icon. The animal has been named Ambystoma quetzalcoatli, a nod to Quetzalcóatl, the feathered-serpent deity of Aztec mythology.

The fossils were recovered in the state of Hidalgo, in the Santa María Amajac area, from sediments laid down in a now-vanished mountain lake. Researchers estimate the creature lived roughly 4.2 million years ago, during the Late Pliocene epoch. It belongs to the genus Ambystoma, the same group that includes the living Mexican axolotl, Ambystoma mexicanum, which survives in the wild today only in a handful of waterways near Mexico City.

What makes the discovery unusual is the completeness of the remains. The specimens are the first complete and articulated ambystomatid salamanders known — a rarity because the bones of these animals are notably thin and fragile and tend to scatter or disintegrate before they can fossilize. Articulated skeletons, in which bones remain in their natural arrangement, give scientists a far clearer view of anatomy than the isolated fragments that usually represent such soft-boned creatures, allowing for confident comparisons with living relatives.

Beyond its scientific value, the find fills a notable gap in the fossil record. According to the team, Ambystoma quetzalcoatli is the first fossil salamander species ever named from Mexico and the oldest known record of the group in the country, anchoring the deep history of a lineage that is otherwise documented mostly through living species. The naming, too, is a deliberate cultural gesture, tying a uniquely Mexican animal to one of the most important figures in the region's mythology.

The research was published online in the journal Palaeontologia Electronica. The work offers a rare window into the ancestry of the axolotl at a moment when its living relatives are critically endangered, squeezed by habitat loss, pollution and invasive species in the canals of Xochimilco.

By tracing how these salamanders looked and lived millions of years ago, scientists hope to better understand the evolutionary path that produced one of the world's most distinctive amphibians — a creature prized in laboratories for its near-magical ability to regrow limbs and organs. The fossils suggest the lineage has weathered enormous environmental change over millions of years, even as the modern axolotl now teeters on the edge of extinction in the wild.