Ancient Snake Fossil Reveals Secret to Losing Limbs

Topic: Biology

Scientists found a 80-million-year-old snake fossil in Brazil that helps explain how snakes lost their limbs and started slithering. The fossil, named Tametara mirim, shows that the earliest snakes likely lived underground, using their bodies as digging tools.

Snakes are everywhere in our legends and mythology. Yet for most of us, our blood runs cold whenever we encounter these strangely undulating, scaly tubes of muscle slithering through the leaf litter. The loss of an arm or leg poses a challenge. Yet snakes do perfectly well without all four of them. This makes them suspect. It also leaves us unable to fathom how this radical transition produced one of the most successful vertebrate body plans.

More than 4,000 species of snakes live today, on every continent except Antarctica, from thread-thin burrowers to massive pythons, on land and in the sea. We have studied them since antiquity, and still the oldest question about them has no answer: What turned snakes into snakes?

A new study published in Nature describes a small, exquisitely preserved fossil that brings us closer to an answer than ever before. The fossil, named Tametara mirim, is from roughly 80-million-year-old rock in São Paulo state, Brazil. It's one of the best-preserved early snakes found anywhere on Earth and the first articulated snake skeleton from Brazil.

The researchers found that the lifestyle of the earliest snakes was encoded in their bones, particularly in the skull. Head-first burrowers build denser, thicker bone in this region to consolidate the skull against the strain exerted during digging. Tametara shows exactly this trait combination, suggesting it lived underground and used its body as a digging tool.

Why It Matters

Understanding how snakes lost their limbs can help us learn more about evolution and how different species adapt to their environments. This knowledge can also inspire new technologies for search and rescue missions or environmental monitoring.

Key Facts

• The fossil, named Tametara mirim, is 80-million-years-old and was found in São Paulo state, Brazil.
• It's one of the best-preserved early snakes found anywhere on Earth and the first articulated snake skeleton from Brazil.
• The researchers believe that the earliest snakes likely lived underground, using their bodies as digging tools.
• More than 4,000 species of snakes live today, on every continent except Antarctica.
• The study was published in Nature, a peer-reviewed scientific journal.

Key Terms

vertebrate

An animal with a backbone or spinal column.

burrower

An animal that digs tunnels and holes in the ground.

articulated skeleton

A fossilized skeleton where all the bones are still connected to each other.

Implications

Understanding how snakes lost their limbs can help us learn more about evolution and how different species adapt to their environments. This knowledge can also inspire new technologies for search and rescue missions or environmental monitoring.