A recently uncovered pterosaur fossil is providing valuable insights into the evolutionary path of these ancient flying reptiles. This well-preserved specimen, named Skiphosoura bavarica, reveals important information regarding the shift from smaller early pterosaurs to their later, much larger counterparts. By studying the distinctive traits of Skiphosoura, paleontologists are able to chart the gradual evolution of pterosaurs, focusing on alterations in head dimensions, neck length, wing structure, and tail size. This significant discovery enhances our understanding of how these extraordinary creatures navigated the skies of the prehistoric era.
Pterosaurs, now extinct, were flying reptiles that coexisted with their close relatives, the dinosaurs. While the largest pterosaurs had wingspans of up to 10 meters, early varieties were typically around 2 meters. This new research, led by paleontologist Dr. David Hone from Queen Mary University of London and published in the journal Current Biology, introduces a new pterosaur species that elucidates this crucial evolutionary transition.
The newly identified species, Skiphosoura bavarica, translates to ‘sword tail from Bavaria’, reflecting its origin in southern Germany and its unique short, stiff, pointed tail. This specimen is notable for being virtually complete and preserved in three dimensions, a rarity since most pterosaur fossils are flattened. In its living state, it would have boasted a wingspan similar to that of large birds, such as golden eagles, measuring about 2 meters.
For over two centuries, scientists have categorized pterosaurs into two primary groups: the early non-pterodactyloids and the later, considerably larger pterodactyloids. The early types were characterized by short heads and necks, along with long tails and a distinct bone structure in their wrists and feet. Conversely, pterodactyloids featured larger heads and necks, along with shorter tails and toes. However, the exact changes occurring between these two classifications remained unclear.
In the 2010s, a variety of transitional species known as darwinopterans was identified, showcasing the shift in head and neck proportions preceding changes in the rest of the body. These findings illustrated a key evolutionary link, but gaps in knowledge about what transpired before and after these developments persisted.
The discoveries associated with Skiphosoura fill in these gaps. Evolutionarily speaking, it falls between the earlier darwinopterans and the pterodactyloids. Skiphosoura exhibits a head and neck similar to the pterodactyloids, but possesses a longer wrist and shorter toe and tail than its darwinopteran predecessors—though not as developed as those in pterodactyloids. This study also presents a revised evolutionary family tree for pterosaurs, highlighting the placement of Skiphosoura and indicating that a Scottish pterosaur named Dearc occupies a mirror position between early pterosaurs and the first darwinopterans.
This means we now have a complete evolutionary sequence from early pterosaurs to Dearc, progressing through the first darwinopterans to Skiphosoura and ultimately to the pterodactyloids. While not every fossil is entirely intact, we can now clearly observe the gradual increases in head and neck size, wrist elongation, and reductions in toe and tail length across multiple groups. This represents a remarkable illustration of a lineage whose evolutionary transitions had previously been unclear.
Both Dearc and Skiphosoura were relatively large for their respective time periods, suggesting that the adaptations enabling pterodactyloids to achieve massive sizes were already emerging in these intermediate species.
Dr. David Hone from Queen Mary University of London remarked, “This is an incredible find. It really helps us piece out how these amazing flying animals lived and evolved. I hope this study serves as a foundation for future research into this critical evolutionary transition.”
Adam Fitch from the University of Wisconsin-Madison noted, “Pterosaurs have long represented the unique prehistoric life. Skiphosoura is a significant new piece for understanding the evolutionary relationships of pterosaurs and how this lineage developed and transformed.”
René Lauer from the Lauer Foundation explained, “The specimen was found disarticulated with bones of varied quality often overlaying one another. Utilizing digital photography in both visible and UV light greatly assisted in identifying these parts and analyzing finer details that were not obvious in typical daylight.” Bruce Lauer from the Lauer Foundation added, “The Lauer Foundation is proud to contribute this important specimen to scientific research and enhance our understanding of pterosaur evolution.”
Stefan Selzer, a contributor to the project who prepared the specimen, stated, “In my work as a preparator, I have handled more than 60 pterosaur specimens from the Solnhofen limestone. During the final preparations, I observed that this fossil exhibited features that combined characteristics from both major pterosaur groups, with the shortened tail being the most distinctive trait.”
