Sailing Ancient Seas

Did Pterosaurs sail, as well as fly?

Tapejara wellnhoferi

Computer rendering shows how Tapejara wellnhoferi might have sailed, catching the wind with its head crest and wings.

Environment: Joe Sharkey; model rendering courtesy Sankar Chatterjee

Paleontologists have long noted that pterosaur wings were like sails, being membranes that could flex in either direction. The resemblance may prove to have been more than passing: preliminary research suggests the piscivorous reptiles sailed the seas as well as the skies during their extended reign from 220 million to 65 million years ago.

Sankar Chatterjee, a paleontologist at Texas Tech University in Lubbock, and three colleagues (one an aeronautical engineer) studied fossils of the crow-size pterosaur Tapejara wellnhoferi. They reconstructed the animal and made a series of models to examine its range of motion, then analyzed its aero- and hydrodynamics with a biomechanical computer simulation.

Landing at sea, a foraging pterosaur could raise its wings to catch a breeze, the team thinks. Strong collagen fibers—much like sail battens—maintained the wings’ shape in the wind. T. wellnhoferi, like many pterosaurs, possessed a huge membranous head crest that the team likens to a jib. And the reptile’s sternum and legs would have contacted the water much as a trimaran’s hulls do. Rigged thus, the team reasons, pterosaurs could skim  across the surface with minimal effort, probably for short distances between bouts of fishing.

The researchers plan to test their ideas with wind-tunnel experiments next year. In fact, they’re developing a robotic drone based on T. wellnhoferi that they expect will be able to fly, walk, and sail. (Annual meeting of the Geological Society of America)