Researchers identified Tametara mirim from Brazil as a new stem snake from about 85–75 million years ago, with micro-CT scans exposing unusually detailed cranial nerves, inner ear and brain anatomy.
The scans and skull-bone analysis point to a fossorial, or burrowing, lifestyle, while showing a brain shape unlike both living snakes and another stem snake, Dinilysia.
The specimen is the first articulated Brazilian snake fossil known from the Cretaceous and preserves part of the skull plus 103 presacral vertebrae, giving one of the clearest views yet of early snake anatomy.
Phylogenetic analyses place Tametara among the earliest-diverging stem snakes, close to Najash, and support a Middle Jurassic origin for snakes with crown snakes arising in the early Late Cretaceous.
The findings argue that early snake evolution was not a single march from one habitat, but involved repeated shifts among burrowing, surface-dwelling and marine lifestyles.
How did the brain of a tiny, ancient snake just rewrite the entire story of their evolution?
This ancient snake burrowed with its head. Was this unique adaptation the key to survival or an evolutionary trap?
Fossil Discovery of Tametara mirim Reveals Earliest Specialized Burrowing Snake and Rewrites Snake Evolution in South America
Overview
The report highlights the groundbreaking discovery and publication of a new fossil snake species, Tametara mirim, found in southeastern Brazil and dating back 85–75 million years. What sets this find apart is its exceptional preservation, featuring a three-dimensionally intact skull and braincase. This rare state allows scientists to study the intricate cranial anatomy of ancient snakes in detail, offering new insights into snake evolution. The species name reflects its unique features: 'Tametara' refers to the pronounced sagittal crest, while 'mirim' denotes its small size, making this discovery a significant milestone in paleontology.