Early Snakes Didn't Pick One Path: Fossils Show They Were Everywhere at Once

Snakes may owe their long, limbless bodies to no single habitat. A newly described fossil from Brazil, named Tametara mirim, suggests that by around 80 million years ago early snakes had already spread across underground, terrestrial and marine environments — settling a long-running debate over whether burrowing or swimming came first.

The Late Cretaceous snake, described from a well-preserved skeleton, shows a compact skull and sensory features associated with life below ground. Researchers used CT scans and 3D reconstructions to study its internal anatomy without damaging the fossil. Comparing it with Dinilysia patagonica, an older snake from Argentina, they found clear differences: where Tametara was built for burrowing, Dinilysia appears better suited to moving and hunting above ground.

That contrast is the point. Rather than following one evolutionary path, different snake lineages adapted to different habitats surprisingly early in their history — and other fossils, from marine and terrestrial deposits, fill out a picture of a group radiating in several directions at once. The elongated, limbless body plan proved flexible enough to work underground, in forests and in water, provided the skull and senses matched the job.

The findings reframe how scientists think about the origins of one of the most successful body designs in vertebrate history. Snakes today live almost everywhere, and this study suggests the ecological versatility that made that possible was there almost from the start.