80-Million-Year-Old Snake Fossil Reveals Complex Early Evolution

An 80-million-year-old fossil discovered in Brazil suggests early snakes occupied diverse habitats, complicating the long-held question of where snakes originated. The remarkably well-preserved specimen, named Tametara mirim, was found in 2020 at a quarry in São Paulo state, in rock dated to 75–85 million years ago. The species name means 'small' in Tupí-Guaraní, and the fossil includes about 60% of the skull and 70% of the vertebral column. High-resolution CT scans revealed a poorly developed vision region, an enlarged inner ear typical of burrowing snakes, and a thick skull, indicating T. mirim lived underground. In contrast, Dinilysia patagonica, an early snake from Argentina dating to around 90 million years ago, had anatomy suited for surface living. Their brain shapes differed substantially from each other and from most modern lizards and snakes, showing significant neuroanatomical diversity early in snake evolution. The study, published July 22 in Nature, was led by Roy Ebel of Museums Victoria Research Institute and Tiago Simões of Princeton University. Evolutionary biologist Michael Caldwell of the University of Alberta called the findings evidence of a dynamic, twisting family tree rather than linear evolution. The research reframes the century-old question of snake origins, suggesting it was never simply a matter of sea or soil.