The New York Times Trilobites column has a story about pterosaur origins. Paleontologists have long wondered about the evolutionary ancestors of pterosaurs as the animals were most likely small and thus less likely to fossilize.  A paper in the journal Nature proposes that Scleromochlus taylori is one of the missing ancestors.  It lived about 237 million years ago in what is now northern Scotland.  The fossils, which are encased in hard sandstone, were found in the early 1900’s.

Few creatures were built to soar like pterosaurs. Tens of millions of years before the earliest birds, these Mesozoic reptiles had pioneered flight with sail-shaped wings and lightweight bones. Eventually pterosaurs the size of small planes would take to the sky, pushing the boundaries of animal aviation.

But the origins of these reptiles have remained murky because of a lack of fossils from the earliest fliers. “The oldest pterosaur we have already had wings and were capable fliers,” said Davide Foffa, a paleontologist at Virginia Tech, which makes it difficult to chart their aerial evolution.

For decades, paleontologists have postulated that the earliest pterosaurs dwelled in trees and experimented with gliding before flying. But Dr. Foffa and his colleagues may have discovered a more ground-bound origin for these ancient aviators. In a study published Wednesday in the journal Nature, the researchers reanalyzed a cache of fossils and concluded that the earliest pterosaur relatives were off to a running start long before they took off.