The Mesozoic era is often associated with giant animals, including various sauropods, large marine reptiles, and pterosaurs with wingspans that could rival those of small aircraft. However, ecosystems 150 million years ago also included many small, fragile species. Most of these delicate animals are rarely found in the fossil record, except in unusual circumstances where specific natural events led to their preservation.
A recent study in Current Biology provides fresh details about how two small pterosaurs from Germany’s Solnhofen Limestone beds met their end during intense tropical storms. In examining their bones, researchers found injuries indicating that strong winds likely broke their wings and caused them to fall into the lagoon. This chain of events, from injury to rapid burial in fine sediments, preserved their remains and offers insight into both their deaths and the frequency of juvenile pterosaurs in Solnhofen’s fossil beds.
Meet Baby Pterosaurs “Lucky I” and “Lucky II”
Researchers from the University of Leicester identified two specimens, called “Lucky” and “Lucky II.” Both are members of Pterodactylus, the first pterosaur described by science. With wingspans of less than eight inches, these hatchlings are among the smallest known flying reptiles. Their skeletons were almost completely intact, except for one important feature.
Each showed the same unusual injury: a clean, slanted break to the humerus. Lucky’s left wing and Lucky II’s right wing were fractured in ways that suggest torsional forces, not blunt impact. Lead author Rab Smyth, who led the analysis, believes the breaks were caused by sudden, violent gusts. “Pterosaurs had incredibly lightweight skeletons. Hollow, thin-walled bones are ideal for flight but terrible for fossilisation,” Smyth explained. “The odds of preserving one are already slim, and finding a fossil that tells you how the animal died is even rarer.”
After being injured, the juveniles fell into the lagoon, where storm-driven waves caused their deaths. Fine sediments rapidly covered their bodies, preserving them in the fossil record.
Survival of the Smallest
The Solnhofen deposits are renowned for their history of fossilized discoveries, including the iconic Archaeopteryx. Hundreds of pterosaur specimens have been uncovered there, but nearly all are small juveniles. Adults, when they appear at all, are represented only by fragments.
At first, it may seem that larger animals with stronger skeletons are more likely to become fossils. However, the new study suggests the opposite. Juvenile pterosaurs, being smaller and less experienced, were more likely to be killed by storms. Their bodies sank quickly and were buried by mud, while adults either survived the storms or, if they died, floated and decomposed before they could be preserved.
“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 who were unfortunately caught up in powerful storms.”
Fossil Bias
Co-author Dr. David Unwin recalled the moment Lucky II was illuminated under UV light, revealing its intact skeleton. “It literally leapt out of the rock at us—and our hearts stopped. Neither of us will ever forget that moment.”
This discovery provides new insight into how catastrophic events can not only cause the deaths of certain members of a species, but also influence which species are preserved and documented in the fossil record. The evidence in Solnhofen suggests that violent storms killed the smallest and most fragile pterosaurs, quickly burying them in lagoon sediments. Larger pterosaurs were more likely to survive these storms or perish on the surface, leaving fewer opportunities for their fossils to be preserved.
In addition to addressing a paleontological question, the study shows how environmental forces, such as ancient storms and modern hurricanes, can have a greater impact on young and vulnerable members of ecosystems. Studying these patterns in the past helps scientists better understand both prehistoric life and the biases that influence our interpretation of evolution.
Austin Burgess is a writer and researcher with a background in sales, marketing, and data analytics. He holds a Master of Business Administration and a Bachelor of Science in Business Administration, along with a certification in Data Analytics. His work combines analytical training with a focus on emerging science, aerospace, and astronomical research.