An unusual Rhamphorhynchus fossil is actually an oversized adult of a known species.
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| As Rhamphorhynchus muensteri (depicted in the reconstruction) aged and grew larger, its needle-like teeth gradually broadened and became more blade-like, possibly suggesting a shift in diet later in the pterosaur’s life. Mark Turner/Alamy |
One pterosaur species underwent a remarkable transformation as it matured.
For over a century, scientists have debated whether a large, anatomically unusual flying reptile fossil belonged to a separate species from its smaller counterparts. However, a study published on January 2 in PeerJ suggests otherwise. Researchers argue that the Jurassic “giant” is simply an oversized example of the same species. These findings shed light on how these extinct fliers may have changed both physically and ecologically throughout their lives.
Rhamphorhynchus, a snaggle-toothed pterosaur, soared over parts of what is now Europe and Africa during the Jurassic Period, around 150 million years ago. It’s among the best-known pterosaurs, with over 100 fossil specimens documented.
However, one nearly complete fossil unearthed in the mid-1800s from limestone deposits in southern Germany stood apart from the rest. While most adult Rhamphorhynchus had a modest 1-meter wingspan—similar to a crow—this particular fossil was much larger, boasting an eagle-like wingspan. Initially classified as a separate species, a 1995 study proposed that all known Rhamphorhynchus fossils belonged to a single species, R. muensteri.
Still, the unusually large specimen raised doubts. “This thing is big and weird,” says David Hone, a paleontologist at Queen Mary University of London. “Maybe this is a different species, and we’ve not really looked at it properly.”
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| Silhouettes illustrate reconstructed sizes and wingspans of Rhamphorhynchus fossil specimens. Arranged counterclockwise from the top left: A represents the smallest known individual, C depicts a “typical” adult, D shows the second-largest specimen discovered, and B features the largest, “giant” individual. D.W.E. Hone and S.N. McDavid/*PeerJ* 2025 |
Paleontologist David Hone and independent researcher Skye McDavid conducted an in-depth analysis of the mysterious skeleton, examining its unusual features in detail.
By meticulously measuring the skull and body of the fossil and comparing them to other Rhamphorhynchus specimens, the researchers uncovered several distinctive traits. The fossilized pterosaur had an impressive 1.8-meter wingspan—over 60 percent larger than all but one of the largest known Rhamphorhynchus specimens. Its eye sockets were proportionally smaller, while the skull openings behind the eyes were noticeably larger.
Despite these differences, the researchers argue that such proportional changes align with the gradual shifts seen in pterosaurs and other animals as they grow. The Jurassic giant, they suggest, represents the fully matured form of R. muensteri.
“It’s a very cool specimen,” says Natalia Jagielska, a paleontologist at the Lyme Regis Museum in Dorset, England. “I’m glad it has finally been described in detail, rather than just mentioned in passing.”
The diet of larger R. muensteri may have included more terrestrial prey, such as lizards or small mammals. As a result, these older individuals might have spent less time near the ocean, instead venturing inland along rivers and estuaries. According to David Hone, this type of ecological separation by age would have been almost inevitable for pterosaurs and dinosaurs, as they started life as tiny hatchlings and likely grew continuously throughout their lives.
“Every single stage of life is a slightly different animal,” says Natalia Jagielska, a paleontologist at the Lyme Regis Museum.
However, not everyone agrees with the idea that the larger individuals changed their diet or habitat. Dave Unwin, a paleontologist at the University of Leicester, argues that the anatomy of R. muensteri is “wholly unsuited” for terrestrial foraging. He believes that the skeletal and dental differences in the larger specimens are simply adaptations to their increased body size rather than evidence of ecological shifts.
Regardless of the debate, studies like this contribute to a better understanding of pterosaur growth and development, says Rudah Duque, a paleontologist at the Federal University of Pernambuco in Brazil.
“For many years, pterosaur species were sometimes described without solid criteria, often due to a lack of comparative material, leading to an overabundance of taxa that likely represent individuals of the same species at different ages or sexes,” Duque explains. Recent fossil discoveries spanning various life stages have improved scientists' understanding of pterosaur biology, though much remains to be uncovered.
Citation:
D.W.E. Hone and S.N. McDavid. "A giant specimen of Rhamphorhynchus muensteri and comments on the ontogeny of rhamphorhynchines." PeerJ, published online January 2, 2025. doi: 10.7717/peerj.18587.