Footprints of pterosaurs discovered in Crayssac, in the south of France, show that, after all, these flying dinosaurs were good hikers.
Although the first pterosaur fossils were discovered more than two centuries ago, scientists had no evidence of how this group of flying reptiles, from the Triassic and Jurassic, walked the earth.
But now, the magazine advances Scientific American, the first known footprints of these creatures, discovered at Plage aux Pterosaures (Praia dos Pterossauros in Portuguese), in Crayssac, in the south of France, give the first clues.
Although more than 30 locations worldwide have fossilized pterosaur footprints, all have been left by pterosaurs known as pterodactyls – a common group in the Upper Jurassic and Cretaceous. These more recent pterosaurs, such as Pteranodon and Quetzalcoatlus, had short tails and toothless jaws, with some reaching the size of small aircraft.
Until recently, experts considered that non-pterodactyl pterosaurs – such as the Rhamphorhynchus – lived in trees and were unable to walk on the ground. However, excavations carried out between 2010 and 2014 by these scientists show alternating footprints of the front and rear legs.
At first glance, the footprints discovered appeared to be of pterosaurs. But when they realized that they had five fingers on their hind legs, the researchers realized the meaning of what they had found – pterodactyls had only four fingers, while non-pterodactyls had five.
According to the same magazine, the footprints also revealed that the front legs of these first pterosaurs had toes turned forward, instead of being twisted to the side, as had been seen in those of their later relatives.
“Although they are morphologically very different from the traces of pterodactyls, these new footprints clearly showed that non-pterodactyls were quadrupeds and good walkers,” explains Jean-Michel Mazin, the paleontologist responsible for the discovery and whose study was published in January in the scientific journal Geobios.