Pterosaurs were the first vertebrates to conquer the airspace, at the time of the dinosaurs they dominated the sky. Palaeontologists in Bavaria have now discovered the fossil of one of the largest known pterosaurs of the Jurassic era. The animal, which was almost perfectly preserved in the Solnhofen limestone, had a wingspan of 2.10 meters but was not yet fully grown. When fully developed, it may have surpassed in size all previously known pterosaurs from this period. The fossil, dubbed Petrodactyle wellnhoferi, also had an unusually large bony head crest, the team reports. The pterosaur’s teeth and anatomy indicate that it could wade in the water and ate small fish and aquatic animals.
The first pterosaurs flew over primeval landscapes as early as 228 million years ago. During the Jurassic and the Cretaceous they produced an impressive variety of forms. Some of them reached almost gigantic dimensions with wingspans of more than twelve meters, other, early forms were only as big as a seagull. A particularly large number of pterosaurs from the Jurassic period were discovered in the fine-grained Solnhofen lithographic limestone of the Franconian Jura, the rock formation in which the first Archeopteryx fossils were also found. The German finds include a pterosaur that used its more than 450 thin, rat-like teeth to filter the water, but also several specimens of the pterodactylus. In 1784 he was the first pterosaur whose fossil was ever described and named.
“Elvis” fossil from the quarry
Now a research team led by David Hone from Queen Mary University of London has identified another pterosaur in the limestone of the Solnhofen Formation. It is a fossil that was discovered in 2010 in the Schaudberg quarry near Mülheim in Bavaria. “The specimen was found in a quarry that produces scientifically important fossils and provides further insight into Late Jurassic pterosaurs,” explains Hone. Because of its large, pompadour-like bony crest on its head, which was already recognizable at the time, it was initially nicknamed “Elvis”. Since then, Hone and his team have studied the 145-million-year-old, well-preserved fossil in detail and classified it phylogenetically. Many details of the pterosaur skeleton only became apparent when analyzed under ultraviolet light. “The use of digital UV-induced fluorescence photography made it possible to detect fine structures of small bones and provided additional information about the structures of the bone crest, which helped in the interpretation and conclusions about this unique new species,” explains co-author René Lauer from the Lauer Foundation.
The investigations revealed that the pterosaur fossil belongs to a new species within the Ctenochasmatoids, a subgroup of short-tailed pterosaurs that were characterized by long, toothed jaws. The filter feeders and Pterodactylus anticuus discovered earlier in the Solnhofen Formation also belong to this group. The new fossil was named Petrodactyle wellnhoferi, which translates as “Wellnhofer’s stone finger,” in honor of German paleontologist Peter Wellnhofer, who devoted his career to studying pterosaurs. The new species is unusually large with a wingspan of 2.10 meters. “It is considerably larger than most taxa known from Solnhofen and similar formations,” report the paleontologists. Some skeletal parts that have not yet fully ossified also suggest that the fossil was not a fully grown specimen. “It is therefore likely that this animal was still growing and potentially would have reached an even larger size,” the researchers said. This makes Petrodactyle wellnhoferi one of the largest known pterosaurs of the late Jurassic era.
Wading piscivore with bone crest
Also unusually large is the bony crest that the animal wore on the top of its long snout. This premaxillary crest, which decreases backwards, is 3.20 centimeters high and 10.4 centimeters long in this fossil. Thus Petrodactyle wellnhoferi had by far the largest known bone crest of all ctenochasmatids, as the paleontologists report. During the lifetime of these pterosaurs, these bony crests probably served as a sexual characteristic, possibly they played a role in the choice of a mate. “As large as this crest is, we know that these pterosaurs had skin-like appendages attached to it, so Pterodactyls must have had an even larger crest when they were alive,” says Hone.
The newly discovered pterosaur 145 million years ago probably lived on the shores of shallow water, wading in the water snapping at small fish or shrimp. This is indicated by the short but sharp teeth of Petrodactyle and a broadened muscle attachment point at the back of the head. The paleontologists conclude from this that the animal must have had relatively strong jaw muscles and a correspondingly strong bite. “This bite was probably important for petrodactyls to catch small fish, but also cephalopods, small crabs and even newly hatched terrestrial vertebrates,” explain Hone and his colleagues. “This shows an ever-increasing range of adaptations in these pterosaurs,” adds senior author Frederik Spindler from the Dinosaur Museum Altmühltal. The young Petrodactyle wellnhoferi preserved in the Solnhofer Plattenkalk thus once again testifies to the rich diversity of these first flying vertebrates on our planet.
Source: David Hone (Queen Mary University of London) et al., Paleontologia Electronica, doi: 10.26879/1251