Overview
- UNAM researchers from the FES Zaragoza collection formally described the new fossil species Ambystoma quetzalcoatli in a paper published in Palaeontologia Electronica, a finding reported by multiple outlets this week.
- The specimen lived about 4 million years ago in a mountain lake near present‑day Santa María Amajac, Hidalgo, and was identified after a detailed reassessment of material held in UNAM collections.
- Investigators used CT scans and 3D analysis to compare the fossil with living Ambystoma species and found unique traits, including an opening on the top of the skull, a different palate layout, and 17 trunk vertebrae versus 16 in modern ajolotes.
- The fossil is the first fully articulated ajolote reported in Mexico and the oldest Ambystoma record for the country, a preservation credited to fine lacustrine sediments that protected the fragile bones.
- Researchers say the discovery suggests ajolote lineage and range were broader in the past and could connect to tiger salamanders, but they stress that more specimens and comparative work are needed to test those evolutionary and biogeographic hypotheses.