Brazilian Cretaceous snake fossil reveals early snake evolution

Scientists have uncovered a remarkably well‑preserved snake fossil in the municipality of Presidente Prudente, São Paulo State, Brazil. The specimen, dated to 75–85 million years ago in the Late Cretaceous, belongs to a newly identified species named Tametara mirim and measured about 42 cm (17 in) in length.

The fossil includes roughly 60 % of the skull and 70 % of the vertebral column, allowing researchers to use high‑resolution CT scanning to digitally reconstruct the brain, cranial nerves and inner ear. Anatomical features such as a dense skull roof and reduced visual centers indicate a fossorial, or burrowing, lifestyle.

Published in *Nature*, the study was led by Tiago Simões (Princeton University) together with collaborators from the University of Helsinki, the University of São Paulo and other institutions. The find provides rare insight into the early evolution of snakes, supporting the hypothesis that the earliest snakes were adapted to life underground and offering the earliest known articulated snake skeleton.

Because such complete Cretaceous snake fossils are exceptionally scarce—only a handful of species are known with comparable preservation—this discovery reshapes understanding of snake origins and their early neuro‑anatomy.