Scaphognathus: the short-headed long-tailed pterosaur

Scaphognathus crassirostris was a long-tailed pterosaur from the Late Jurassic lithographic limestones of Bavaria. Several skeletons preserve a short, high skull and large, widely spaced teeth. The holotype also retains impressions of a wing membrane and hair-like covering, but these traces do not provide a complete colour reconstruction.

Georg August Goldfuss described the first specimen in 1831 as Pterodactylus crassirostris. Its tail is missing or very incomplete, which contributed to an early mistake about its relationships. A second, younger but more complete skeleton preserved the long tail and showed that the animal was not a short-tailed pterodactyloid.

Evidence note

Scaphognathus is unusually informative because bone and soft-tissue traces occur together. Its exact colour, adult growth pattern and individual hunting behaviour are not preserved.

Quick facts

The first skeleton and the missing tail

Goldfuss described the type material from Bavaria's lithographic limestone in 1831. The slab and counterslab, IGPB Goldfuß 1304a and 1304b, preserve the skull, neck, trunk and much of the limbs, but not a clear complete tail series. He compared the animal with pterodactyls then known and named it “thick-snouted” for its robust head.

Later, a second skeleton with a long tail showed that Scaphognathus belonged among the long-tailed pterosaurs. The discovery changed the interpretation of the first specimen: absence of a structure in the holotype was not evidence that the living animal lacked it. Goldfuss's reconstruction also gave it four clawed free fingers, whereas pterosaurs had three free fingers and an elongated fourth finger supporting the wing. His observations of membrane and hair-like impressions, however, were substantially borne out by later study.

A short skull and widely spaced teeth

The skull was shorter and taller than that of Rhamphorhynchus, with separated external nostril and antorbital openings. The large eye socket and the rear of the skull provided room for jaw muscles. An updated description counted sixteen teeth in the upper jaw. Earlier counts were higher because replacement teeth had been treated as additional positions.

The crowns were large, slightly curved and widely spaced. Lower teeth fitted between the upper row as the mouth closed. This arrangement could grip discrete prey, unlike the closely set teeth associated with filtering in some other pterosaurs. Fish and large insects fit the mechanics, but no stomach content securely tied to Scaphognathus establishes the diet. It is safer to say its food remains uncertain than to call it exclusively piscivorous.

Skeleton, growth and flight

Several smaller specimens have unfused bones and proportions consistent with younger animals. One articulated juvenile helped clarify the number of neck vertebrae and the proportions of the limbs. Differences from the larger holotype may reflect growth and should not automatically be used to name separate species.

The forelimb carried a wing membrane supported by a greatly elongated fourth finger; the three shorter fingers ended in claws. The hind legs were developed, and the tail was long with strengthened vertebrae. A tail vane is better known in related pterosaurs than in Scaphognathus, so its exact shape in reconstructions is uncertain.

Modern imaging under ultraviolet and changing light has confirmed membrane traces noted by Goldfuss. Actinofibrils, fine fibres within the wing, helped reinforce and shape the membrane. Hair-like impressions are interpreted as pycnofibres, the pterosaur's own body covering rather than mammalian hair. They are consistent with insulation, but their length and density may have varied over the body.

The fossils do not preserve original colours, spots or stripes. Hair-like fibres are not proof of complex branching feathers across the whole body. A reconstruction can show a soft covering where traces support it, while leaving colour and exact pattern open.

The Solnhofen environment

The thin lithographic limestones formed in lagoons across an archipelago on the margin of the Tethys Sea. Restricted water exchange and oxygen-poor bottom conditions slowed decay, preserving articulated skeletons, membranes and small bones that are usually lost.

Scaphognathus shared the region with other pterosaurs, fish, marine reptiles, invertebrates and small dinosaurs. Burial in lagoon sediment does not prove that it fed over open water. It could have used islands, shorelines and airspace over shallow lagoons. Other Jurassic long-tailed pterosaurs show varied head and tooth proportions, but comparison alone cannot reveal the animal's hunting behaviour.

The pterosaur catalogue sets Scaphognathus beside other forms while keeping the distinction between its preserved soft tissues and reconstructed flight scene clear.