Researchers at the National Autonomous University of Mexico (UNAM) have identified a new fossil species of axolotl, Ambystoma quetzalcoatli, in Hidalgo state.This discovery, published in Palaeontologia Electronica, highlights the presence of axolotls in Mexico for millions of years.

The fossils, found in Atotonilco el Grande, exhibit significant anatomical differences from modern axolotls, including an elongated skull opening, unique palate structure, and 17 trunk vertebrae—more than modern species.The study used CT scans and comparisons with 13 living Ambystoma species to confirm the new species.The findings suggest neoteny, a trait allowing juvenile characteristics to persist into adulthood, was present in ancient axolotls.This discovery underscores Mexico's deep evolutionary history and the role of ancient lake systems in biodiversity.The research emphasizes the importance of preserving ecosystems and understanding past environmental conditions that shaped current species.