Palaeontologists at the University of Leicester have solved a 150-million-year-old puzzle: how two baby pterosaurs met their end. According to a new study published in Current Biology, the young reptiles perished in violent storms, which also created the perfect conditions for their exceptional preservation in stone.

Fragile Creatures in a Fossil World of Giants

The Mesozoic Era, often remembered as the “Age of Reptiles,” is typically associated with giant dinosaurs, marine predators, and vast-winged pterosaurs. However, as in today’s ecosystems, smaller animals were far more abundant. Unfortunately, their delicate skeletons rarely fossilised, leading to an incomplete picture of ancient life.

One rare exception is the Solnhofen Limestones of southern Germany, a world-famous fossil site dating back 150 million years. These lagoon deposits have produced some of the most detailed fossils known, including many pterosaurs. Yet, while hundreds of small, perfectly preserved juveniles have been unearthed, adults are rarely found, and usually only in fragments. This paradox has puzzled scientists for decades.

Breakthrough Discovery: “Lucky” and “Lucky II”

The turning point came with the discovery of two hatchling pterosaurs nicknamed “Lucky” and “Lucky II.” Belonging to the species Pterodactylus—the first pterosaur ever described—each had a wingspan of less than 20 cm (8 inches). Remarkably, their skeletons are almost entirely intact, except for a striking detail: both had broken wings, each fractured in a similar way.

Lead author Rab Smyth, from the University of Leicester’s Centre for Palaeobiology and Biosphere Evolution, explained:

“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 injuries—clean, slanted breaks to the humerus—suggest that the hatchlings were caught by violent gusts, twisted mid-air, and driven into the lagoon below. There, storm-driven waves drowned them before they quickly sank and were buried by fine mud stirred up by the tempest. This rapid burial accounts for their exceptional state of preservation.

A Stormy Explanation for Fossil Bias

The study suggests that these hatchlings were not alone. Many other small pterosaurs from Solnhofen were likely victims of similar storms, even if their bones show no trauma. Unable to withstand the winds, they were swept from nearby islands into the lagoon, where they were buried in sediments.

In contrast, larger, stronger adults were far more likely to survive storms. Those that did eventually die may have floated for days on calm lagoon waters, slowly decaying and leaving behind only partial remains.

“For centuries, scientists believed that the Solnhofen lagoon ecosystems were dominated by small pterosaurs,” said Smyth. “But we now know this view is deeply biased. Many of these pterosaurs weren’t native to the lagoon at all. Most are inexperienced juveniles that were likely living on nearby islands that were unfortunately caught up in powerful storms.”

Co-author Dr David Unwin added:

“When Rab spotted Lucky we were very excited but realised that it was a one-off. Was it representative in any way? A year later, when Rab noticed Lucky II we knew that it was no longer a freak find but evidence of how these animals were dying. Later still, when we had a chance to light-up Lucky II with our UV torches, it literally leapt out of the rock at us – and our hearts stopped. Neither of us will ever forget that moment.”

Summary of Findings

• Two baby pterosaurs (Pterodactylus) were found with broken wings, preserved in Germany’s Solnhofen Limestones.
• Evidence suggests they were killed during violent storms, then rapidly buried in lagoon sediments.
• This discovery explains why juvenile fossils are far more common than adult ones at the site.
• Smaller pterosaurs were likely swept from nearby islands into the lagoon, while adults survived storms but decomposed more slowly, leaving fewer complete remains.

The findings reveal that storms played a critical role in shaping the fossil record of the Solnhofen deposits.

Original Publication
Authors: Robert S.H. Smyth, Rachel Belben, Richard Thomas and David M. Unwin.
Journal: Current Biology
DOI: 10.1016/j.cub.2025.08.006
Article Title: Fatal accidents in neonatal pterosaurs and selective sampling in the Solnhofen fossil assemblage
Article Publication Date: 5-Sep-2025

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