Arthurdactylus

In 1994 Eberhard Frey and David Martill named Arthurdactylus conandoylei, the first known pterosaur from the Lower Cretaceous Crato Formation of northeastern Brazil. The species is named for Sir Arthur Conan Doyle, author of the 1912 novel “The Lost World,” which recounts an expedition that discovered living dinosaurs and pterosaurs in the same region of Brazil. 

The species is known from a single partially articulated specimen missing its head, neck, and tail. The wings are extremely long, even for soaring pterosaurs, with a wingspan of 4.6 m (15 feet), but a torso only 22 cm (9 inches) long. The scapulae are relatively short and were perpendicular to the vertebral column. Their distal ends articulated with the notarium, a ridge of bone on the back formed from several fused neural spines. 

The legs were roughly 50 cm (20 inches) long, lightly built with a reduced or absent fibula and especially short feet. Its pelvis is distinctive, with a prominent elliptical notch between the pubis and ischium. This specimen appears to be nearly fully grown, but the sacral ribs were not fused to the illia. This feature may be linked to laying eggs, indicating that this individual may have been a female. 

When Frey and Martill first named Arthurdactylus in 1994 they tentatively assigned it to the Ornithocheiridae. A more recent review of Crato Formation pterosaurs published by David Unwin and David Martill in 2007 confidently linked it to that family. They note that the combination of scapulae perpendicular to the spinal column, extremely long and narrow wings, a short torso, and short hind-limbs are only found in ornithocheirids. 

These pterosaurs were aerial fishers and were common in Early Cretaceous marine environments with several species now known in the Crato and overlying Santana Formation of northeastern Brazil. Most ornithocheirids had long tapering jaws lined with dozens of sharp teeth. Many had semi-circular crests at or near the tips of their jaws, and it’s possible Arthurdactylus did too.