Coprolites are a subset of the broader field of bromalites, which have equally embarrassing origins, Hunt added.

"There's also fossil vomit," he said. "I've coined those regurgitalites. And sometimes digested food stays in the intestines when an animal dies, and we call those cololites. Those two and coprolites make up the larger field of bromalites."

Having eaten dozens of belemnites, an ichthyosaur would regurgitate their indigestible bullet-shaped shells in much the same way that an owl does after eating a mouse whole, the scientists announced Tuesday. It is these shells that have been discovered in the fossil vomit.

The world's oldest fossilised vomit has been uncovered near the English town of Peterborough.

But far from turning up their noses, palaeontologists are excited by the discovery of "copious quantities" of Jurassic puke, says Peter Doyle of the University of Greenwich. The regurgitations came from the mouths of ichthyosaurs swimming in the waters that covered England 160 million years ago and were found by Doyle in a clay quarry.

"We believe this is the first time the existence of fossil vomit on a grand scale has been proven beyond reasonable doubt," Doyle told New Scientist.