Scientists have discovered how snakes lived during the age of the dinosaurs

The new species has been named Tametara mirim. Its remains were found in Late Cretaceous deposits in south-eastern Brazil.

According to the researchers, this is one of the most complete fossilised skeletons of ancient snakes ever found. Using computed tomography, the scientists were able to examine the skull in minute detail without damaging the specimen. They reconstructed the inner ear, the nerve channels and the shape of the cavity that once housed the brain.

It is important to note that this does not refer to the brain itself being preserved as soft tissue. The scientists created a digital model of it based on the internal shape of the skull.

This snake had adapted to life underground

The shape of the interior of Tametara mirim’s skull proved to be unusual. The scientists compared it with data from more than 100 modern snake species whose lifestyles are well known.

The results showed that Tametara was adapted to burrowing and living underground. An independent study of its bone structure led to the same conclusion.

It is likely that this small snake spent a significant portion of its time in the ground or loose soil, and the characteristics of its sensory organs were suited to this way of life.

But another ancient snake lived quite differently

The researchers then studied Dinilysia patagonica — an ancient snake from Argentina that lived during roughly the same geological period.

Its anatomy turned out to be completely different. Analysis showed that Dinilysia was predominantly a terrestrial animal and did not exhibit such a pronounced specialisation for subterranean life.

Furthermore, scientists have long been aware of the remains of Cretaceous snakes found in marine deposits. Taken together, these findings suggest that, even in the early stages of their evolutionary history, different lineages of snakes had already adapted to subterranean, terrestrial and marine environments.

Details

The origin of the snake’s characteristic long, limbless body has been debated for over a century.

One hypothesis suggested that this form evolved in ancestors that burrowed through the ground and moved through narrow underground passages. Another linked the loss of limbs to life in water.

New research shows that the question cannot be reduced to a simple choice between land and sea. Early snakes began to adapt to different environments quite rapidly, and their evolution did not follow a single, straight path.

That said, the study does not prove that the very first ancestor of all snakes lived specifically underground or in water.

According to the authors’ calculations, the ancient common ancestor was most likely not yet narrowly adapted to a single environment and occupied an intermediate position between a terrestrial and a burrowing lifestyle.

One of the most unusual findings relates to the diversity of the sensory organs.

Digital models have shown that the internal structure of the skulls of Tametara and Dinilysia differed markedly not only from one another but also from that of most modern snakes.

This suggests that, tens of millions of years ago, different species were already able to perceive the world around them in different ways and adapt their sensory organs to their respective environments. The authors believe that diversity in brain structure and lifestyle emerged in snakes much earlier than a simpler model of their evolution had suggested.

Why this is important

Today, more than 4,000 species of snakes are known — ranging from burrowing forms to arboreal and entirely marine species. The new study shows that the foundations of this diversity began to take shape as far back as the age of the dinosaurs.

The discovery also demonstrates just how much information can be gleaned even without preserved soft tissues. Modern tomography allows us to peer inside a fossilised skull and, based on its shape, reconstruct the features of the sensory organs of a long-extinct animal.

However, the study does not provide a definitive answer to the question of the origin of the first snakes. Their early history remains very incomplete, so new discoveries may supplement or alter the existing picture.

Source

Study: Tiago R. Simões et al. Exceptional brain and ecological diversity in the earliest snakes.

Journal: *Nature*, 2026.