Scientists unearth 150-million-year-old fossil in the oddest place — but it was the cause of death that alarmed them

Fossils discovered in southern Germany revealed intriguing insights about pterosaurs that once existed in the area. Findings regarding these remains have been published in the journal Current Biology. The discoveries reveal how these creatures died and how others of their kind also likely met their ends. The insights also challenged past assertions about the dominance of these reptiles in the area. In total, the remains of two individuals were found at the site. These individuals were named Lucky and Lucky II. Unfortunately, they were not as fortunate as their names, according to the findings.

Discovery of the Juvenile Pterosaurs

Lucky was the first of the lot uncovered in the Solnhofen Limestones fossil, according to Discover Wildlife. Lead author Rab Smyth from the University of Leicester was the one who spotted the remains. "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," Smyth shared. At first, the team believed it could be a one-off instance, but when Lucky II appeared, they were sure that there may be a common cause of death involved, not only for these two but also for others of their kind as well.

Further examinations revealed both fossils to be around 150 million years old. Researchers were astounded to see the remains in such exceptional conditions. Experts associated the cause of death with these two creatures with others of their kind, as fossils of juvenile pterosaurs like them are abundant in this specific region of Bavaria. "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," co-author Dr David Unwin from the University of Leicester shared. 

Similarity Between Lucky and Lucky II

Several features were noted in the remains of these pterosaurs, according to the University of Leicester. Both were just a few days or weeks old at the time of death. These two stood out from other young pterosaurs found preserved in the same way in the Solnhofen Limestones due to their evident skeletal trauma. Both exhibited the same kind of injury, a clean and slanted fracture on the humerus. These creatures were identified to be of the Pterodactylus genus, and had wingspans measuring less than 20 inches. These findings made them some of the smallest of all known pterosaurs. Investigations revealed that the skeletons were whole, articulated, and virtually unchanged from the time of their death. One notable difference was that Lucky's left wing was broken, while in Lucky II's case, the right wing had been hampered. 

Speculated Cause of Death

Researchers believe a powerful twisting force hampered the wings, which is speculated to have been triggered by ancient tropical storms. The theory claims that after suffering injury from a storm, these pterosaurs fell into the lagoon and drowned in the waves. Soon they sank under the seabed, where incoming mud triggered by the storm buried them quickly. The rapid pace of burial facilitated the remarkable preservation of Lucky I and Lucky II. The same quality of preservation can be seen in other pterosaur specimens in the Solnhofen Limestones. Though they have no evidence of trauma, similar preservation quality indicates that they were also affected by storms in their last moments. 

This finding solves the mystery of only juvenile pterosaurs being so common in the Solnhofen Limestones and not adult specimens. The adults possibly withstood the storm and flew to their safety, something which the young ones couldn't. In the past, experts attributed the difference to small pterosaurs dominating Solnhofen lagoon ecosystems. "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," Smyth explained.