Research reveals storms doomed baby dinos 150 million years ago

By Dean Murray

Violent storms were the cause of death for two baby pterosaurs, according to research by the University of Leicester.

The skeletons of the ancient winged creatures were found mostly intact, but damage to their wing bones suggests they met their demise as a result of powerful gusts of wind rather than a collision with a hard surface.

Ironically nicknamed Lucky and Lucky II by the researchers, the two individuals belong to Pterodactylus, the first pterosaur ever scientifically named, and lived around 150 million years ago.

With wingspans of less than 20 cm (8 inches), the hatchlings are among the smallest of all known pterosaurs.

The University of Leicester said: "Their skeletons are complete, articulated and virtually unchanged from when they died. Except for one detail. Both show the same unusual injury: a clean, slanted fracture to the humerus.

"Lucky’s left wing and Lucky II’s right wing were both broken in a way that suggests a powerful twisting force, likely the result of powerful gusts of wind rather than a collision with a hard surface."

Catastrophically injured, the pterosaurs are thought to have plunged into the surface of a lagoon, drowning in the storm-driven waves and quickly sinking to the seabed, where they were rapidly buried by very fine limy muds stirred up by the death storms.

"This rapid burial allowed for the remarkable preservation seen in their fossils," said the university.

The study, published in the journal Current Biology, details the fossils found preserved in the renowned Solnhofen Limestones, a Jurassic limestone geological formation located in southern Germany.

While Solnhofen has yielded hundreds of pterosaur fossils, nearly all are very small, very young individuals, perfectly preserved. By contrast, larger, adult pterosaurs are rarely found, and when they are, they’re represented only by fragments, such as isolated skulls or limbs.

This pattern runs counter to expectations: larger, more robust animals should stand a better chance of fossilisation than delicate juveniles.

Lead author of the study, Rab Smyth, from the University of Leicester’s Centre for Palaeobiology and Biosphere Evolution, said: "Pterosaurs had incredibly lightweight skeletons. Hollow, thin-walled bones are ideal for flight but terrible for fossilisation.

"The odds of preserving one are already slim and finding a fossil that tells you how the animal died is even rarer.

"The discovery of two baby pterosaurs with broken wings has helped to solve this mystery. These tiny fossils, though easily overlooked, are powerful evidence of ancient tropical storms and how they shaped the fossil record."