Paleontologists have discovered and described a new ctenochasmatid pterosaurian mandible from the Late Jurassic Portland Limestone Formation of southern England.
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Life reconstruction of the ctenochasmatid pterosaur Gladocephaloideus jingangshanensis. Image credit: Zhao Chuang.
“Pterosaur remains are rare in the Upper Jurassic layers of the United Kingdom, consisting mostly of isolated bones or fragments of bones,” said University of Portsmouth paleontologists Roy Smith and David Martill.
“Many records of Late Jurassic pterosaurs in the United Kingdom are of little more than historic interest, and include named species now regarded as nomina dubia.”
“Nonetheless, some material is diagnostic, and several species have stood the test of time.”
“By far the majority of Upper Jurassic pterosaurs in the United Kingdom have come from the Kimmeridge Clay Formation of southern England, with just a few occurrences from the Oxfordian part of the Oxford Clay Formation of southern and eastern England, and a single occurrence from the Kimmeridge Clay Formation of Scotland.”
“Despite this dearth of material, there have been some occurrences of associated material and the near complete skull of Cuspicephalus scarfi at the type locality of the Kimmeridgian stage.”
The new pterosaurian specimen is a mandible with at least two, possibly three teeth.
The fossil dates back to the Tithonian age of the Late Jurassic epoch, approximately 147 million years ago.
It represents the geologically youngest Jurassic pterosaur from the United Kingdom.
“The specimen is an isolated mandible lacking most of the postsymphyseal parts of the rami,” the paleontologists said.
“It is identified as pterosaurian on account of its very thin compacta and elongate form of the mandible.”
The new specimen was found in the Portland Limestone Formation of Dorset, southern United Kingdom.
It represents the first pterosaur skull material to be documented, described and figured from this formation.
“The specimen was likely first found when a quarryman split the stone using the standard ‘feather and wedge’ procedure,” the researchers said.
“This resulted in damage to the middle part of the specimen, whilst splitting of the jaw along its length also damaged the specimen. The counterpart appears not to have been recovered.”
A lack of diagnostic features prevents the fossil’s referral to a known or new species but it can be confidently assigned to the pterosaur clade Ctenochasmatoidea.
“Ctenochasmatoids are a diverse group of pterosaurs with most genera notable for elongate, slender teeth closely spaced in long, sometimes dorsally curved jaws,” the scientists said.
“Indeed, one form, the South American Pterodaustro, has among the longest teeth in terms of length-diameter ratio of any tetrapod.”
“The basal euctenochasmatian Pterodactylus antiquus and ctenochasmatoid Ardeadactylus longicollum, both of Tithonian age, have short conical teeth with a wider alveolar spacing than those of their ctenochasmatid allies.”
“The elongate slender mandible and numerous closely spaced alveoli suggest it is a member of Ctenochasmatidae.”
“A faint median ridge on the occlusal surface between two grooves, converging into a median groove anteriorly, and the lack of a distinct premaxilla suggest the specimen is part of the symphysis of the mandible.”
“This is the first documented record of a pterodactyloid from the Portland Group of England.”
The findings were published this month in the Proceedings of the Geologists’ Association.
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Roy E. Smith & David M. Martill. A ctenochasmatid pterosaur from the Portland Limestone Formation (Late Jurassic, Tithonian) of southern England. Proceedings of the Geologists’ Association, published online March 11, 2025l doi: 10.1016/j.pgeola.2025.101100
