Tale of two reptiles

Fossils of an ancient snake wrapped around a dinosaur enraptures scientists

By Tiasa Adhya
Published: Saturday 15 May 2010

one stormy day a snake was hungry. The 3.5-metre-long reptile spotted a half-metre infant dinosaur struggling out of its eggshell. Slithering into its unguarded nest, the snake curled up next to the hatchling ready to strike—something it was not destined to accomplish. A downpour must have impacted a stream nearby and mud went surging out to the nest. Both predator and prey were preserved in a moment of action. About 67 million years later, Dhananjay Mohabey of the Geological Survey of India (gsi) happened to be near the village of Dholi Dhungri in Gujarat, at the spot where the reptiles lay buried. The year was 1984.

When his team struck the remains, Mohabey correctly identified the dinosaur and the egg.

But there was more to the specimen which he could not identify. Intrigued by the report he published, Jeffrey Wilson paid him a visit. A palaeontologist from usa’s Michigan University, Wilson was amazed to find a snake’s backbone.

Peering thr-ough gsi’s archives, the two researchers found another block that contained a set of unidentified bones—the missing piece of the puzzle; it completed the loop of the snake’s coils around the dinosaur.

It then took years of negotiations with the Indian Government before the snake (Sanajeh indicus) could be taken to Michigan and analyzed. “What emerged was extraordinary—an egg and a chain of coiled snake bones with a skull. We hardly have good snake skeletons,” Wilson said. The Michigan University with gsi published the find in PLoS Biology on March 2, 2010.

The study opens a world for palaeontologists, ecologists, and enthusiasts of an era when mammoth creatures roamed the planet. Most of all, it provides insight into the ancient food chain that could help clear the enigma surrounding the evolution of snakes; they are thought to have appeared towards the tail-end of the dinosaurs’ epic reign.

Modern boas and pythons are notorious for their expandable mouths allowing them to consume prey shockingly bigger than their heads. This is because their jaw joints are positioned well behind their skulls. S indicus had a smaller mouth. “Its jaws would have allowed Sanajeh to wriggle, mouth first, over a struggling prey in a side-to-side motion depicting oral mobility familiar to anyone squeezing into a tight pair of jeans,” said Jason Head, biologist from University of Toronto in Canada who led the study.

Neither did Sanajeh have the fixed skulls of primitive snakes, nor could its mouth open as wide as today’s boas. “It must be a connecting link,” said Shanan Peters, geologist from the University of Wisconsin-Madison in usa and co-author of the study. “It points to an interesting evolutionary strategy for snakes to eat large prey,” said Wilson.

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