According to researcher Smyth, the scarcity of adult specimens in the fossil record from this region can be attributed to two main factors: a higher survival rate for adults and the slower burial process for those that did not survive. In contrast to juveniles, carcasses of adult pterosaurs were likely to remain afloat for an extended period, with decomposition causing parts to eventually settle on the lagoon floor. Juveniles, being smaller, were more quickly buried by sediments, increasing their chances of preservation.
Injuries Identified
The discovery of humerus fractures in the juvenile pterosaurs known as Lucky I and Lucky II is noteworthy, as forelimb injuries are prevalent among current flying vertebrates. The humerus, essential for wing attachment and experiencing significant flight stress, is particularly vulnerable to injury. Most fractures of this bone occur during flight rather than due to impacts with objects like trees or cliffs. These fractures represent the sole skeletal trauma observed in juvenile pterosaur specimens from the Solnhofen region.
Evidence indicating that the injuries occurred prior to death includes the misalignment of bones while still airborne—comparable to fatalities experienced by modern birds and bats during storms—as well as the smooth edges of the bone breaks, indicative of injuries sustained during life rather than after death. No signs of healing could be detected on the fractures either.
Flying creatures at Solnhofen faced significant risks from storm systems, which could knock them down with powerful winds. Among the fossilized remains from this area, many belonged to pterosaurs and early bird species such as Arachaeopteryx. Additionally, flying invertebrates faced similar threats.
Marine life, including fish and invertebrates, also suffered during storm conditions, as turbulent waters brought deeper, saltier, and low-oxygen layers to the surface. Organisms that sank to the bottom were exceptionally preserved due to these harsh circumstances, which deterred scavengers and slowed decomposition. The mud stirred up by storms played a further role in fossilization, quickly burying and protecting these organisms from environmental effects.
“The storms responsible for the burial of these individuals also likely caused their injuries and deaths by transporting the pterosaurs into lagoonal basins,” Smyth concluded.
Despite the unfortunate fate of Lucky I and Lucky II, the remarkably well-preserved skeletons have provided crucial insights into their demise, allowing researchers to solve a mystery that remained unsolved for over a hundred thousand years.
Current Biology, 2025. DOI: 10.1016/j.cub.2025.08.006
