A partial wing bone from a huge, Jurassic pterosaur has been unearthed south of Oxford. The Abingdon pterosaur discovery suggests that some Jurassic pterosaurs had wingspans in excess of three metres. The fossil bone (specimen number EC K2576) was found when strata representing the Upper Jurassic was exposed on the floor of a gravel quarry. The fossil bone is not complete. It consists of three pieces but from this single bone, a size of the overall wingspan can be estimated. The wing bone is believed to be around 148 million years old (Tithonian faunal stage of the Late Jurassic).
Left wing phalanx 1 of a pterodactyloid pterosaur from the Kimmeridge Clay Formation of Abingdon, Oxfordshire. The specimen number is EC K2576. Original specimen (A) and B, simplified interpretive drawing. Scale bar = 10 mm. Picture credit: University of Portsmouth.
The Abingdon Pterosaur Discovery
In the early summer of 2022, geologist Dr James Etienne came across the well-preserved specimen when exploring temporary exposures of the Kimmeridge Clay Formation. Numerous other fossils were found including ammonites and bivalves that acted as biostratigraphic markers, helping to confirm the edge of the deposits. In addition, fossils of sharks and a vertebra from a marine crocodile were found. Several bones from ichthyosaurs and plesiosaurs were also identified.
Researchers from the universities of Portsmouth and Leicester collaborated with Dr Etienne and a scientific paper outlining this discovery has been published. The wing bone has been assigned to an adult ctenochasmatoid (Ctenochasmatoidea clade). This clade of pterosaurs was globally distributed. They tended to have slender wings, long hind legs, elongate and narrow jaws lined with bristle-like teeth. Their fossils are associated with aquatic environments. The three pieces of bone that have been found represent the first phalanx from the left wing.
A life reconstruction of the Abingdon pterosaur based on a typical ctenochasmatoid pterosaur. Picture credit: Hamzah Imran.
The picture (above) shows a life reconstruction of a typical ctenochasmatoid pterosaur. It was drawn by University of Portsmouth student Hamzah Imran.
Co-author of the scientific paper, Professor David Martill (University of Portsmouth), stated:
“When the bone was discovered, it was certainly notable for its size. We carried out a numerical analysis and came up with a maximum wingspan of 3.75 metres. Although this would be small for a Cretaceous pterosaur, it’s absolutely huge for a Jurassic one!”
Map showing locality of the newly discovered pterodactyloid pterosaur wing phalanx EC K2576 from the Kimmeridge Clay Formation. Picture credit: University of Portsmouth.
Professor Martill added:
“This fossil is also particularly special because it is one of the first records of this type of pterosaur from the Jurassic period in the United Kingdom.”
The Size of Jurassic Pterosaurs
Whilst many of the Cretaceous pterosaurs were gigantic, most Jurassic and Triassic pterosaur genera were much smaller. Most early Mesozoic pterosaurs had wingspans of around one or two metres. However, this Abingdon pterosaur discovery, suggests that some Jurassic flying reptiles could grow much larger.
With an estimated wingspan of around 3.75 metres, this gives the Abingdon pterosaur a wingspan comparable to the largest living, volant birds. The pterosaur has not been formally named, but the researchers nicknamed the pterosaur “Abfab”.
Co-author of the paper, Dr Dave Unwin (University of Leicester), explained:
“Abfab, our nickname for the Abingdon pterosaur, shows that pterodactyloids, advanced pterosaurs that completely dominated the Cretaceous, achieved spectacularly large sizes almost immediately after they first appeared in the Middle Jurassic right about the time the dinosaurian ancestors of birds were taking to the air.”
A Reappraisal of the Size of Dearc sgiathanach
In early 2022, a paper was published (Jagielska et al) that described a large pterosaur from the Isle of Skye. This pterosaur was named Dearc sgiathanach. These fossils represent the most complete skeleton of a Middle Jurassic pterosaur ever found in the UK. Wingspan estimates for Dearc vary, with estimates ranging from 1.9 to 3.8 metres. As part of the analysis of the Abingdon ctenochasmatoid phalanx the researchers re-examined the wingspan calculations for Dearc sgiathanach.
Dearc is geologically much older than the Abingdon specimen. It is also a very different type of pterosaur. It is a rhamphorhynchine. The humerus of Dearc is substantial. It measures 112 mm in length. It is one of the largest Jurassic pterosaur humerus fossils known, but larger humeri, most notably from the geologically younger Solnhofen Limestone deposits of Germany have been described.
To read Everything Dinosaur’s blog post about the scientific description of Dearc sgiathanach: Fantastic Pterosaur Fossil from the Isle of Skye.
Challenging Conclusions Made in the 2022 Dearc sgiathanach Paper
The research team challenged the conclusions made by Jagielska et al in their 2022 paper. They contest that the calculation of wingspan size for Dearc sgiathanach was based on a close comparison with the highly derived rhamphorhynchine Rhamphorhynchus. Rhamphorhynchus had a long forelimb and relatively elongate wing-finger. However, phylogenetic analysis suggests that Dearc was not closely related to Rhamphorhynchus. It was more closely related to basal rhamphorhynchines such as Angustinaripterus. Comparing the wing bones of Dearc to more closely related pterosaurs (Angustaripterini) led this research team to conclude that Dearc was still a sizable Jurassic pterosaur, but its wingspan was probably around two metres.
A selection of outlines of large Jurassic pterosaur wingspans. Left pterodactyloids, right ‘rhamphorhynchoids’. Dual silhouettes indicate the lower and upper end member estimates on wingspan based on comparative morphological analysis. Dearc sgiathanach based upon revised wingspan estimate in this study. Picture credit: University of Portsmouth.
The Abingdon Pterosaur Discovery Represents one of the Largest Jurassic Flying Reptiles Known to Science
Professor Martill commented on the Abingdon pterosaur discovery:
“This specimen [specimen number EC K2576] is now one of the largest known pterosaurs from the Jurassic period worldwide, surpassed only by a specimen in Switzerland with an estimated wingspan of up to five metres.”
Everything Dinosaur acknowledges the assistance of a media release from the University of Portsmouth in the compilation of this article.
The scientific paper: “A ‘giant’ pterodactyloid pterosaur from the British Jurassic” by James L. Etienne, Roy E. Smith, David M. Unwin, Robert S.H. Smyth, and David M. Martill published in the Proceedings of the Geologists’ Association.
The Everything Dinosaur website: Dinosaur and Prehistoric Animal Models.
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