Ancient Axolotl Fossil in Mexico Redefines Its Deep Evolutionary History
UNAM researchers describe Ambystoma quetzalcoatli, the first formally identified fossil salamander from Mexico and the oldest Ambystoma record in the country, based on scans of specimens from Hidalgo. The fossils show distinctive skull and skeleton features, including an elongated skull opening, a unique palate, and 17 trunk vertebrae, setting it apart from living axolotls. By comparing with 13 extant Ambystoma species and modern CT data, they concluded the species likely exhibited neoteny and lived in a Pliocene-era lake system, expanding our understanding of axolotl evolution and Mexico’s ancient biodiversity.