A 160-Million-Year-Old Pterosaur and Its Egg Are Discovered

Scientists have found a 160-million-year-old preserved fossil of a pterosaur, along with one of its eggs. Pterosaurs were flying reptiles of various sizes that successfully coexisted with dinosaurs from the late Triassic period to the Cretaceous period.

(Details of the egg preserved in association with an adult Darwinopterus. The scale bar is 10 mm.)

Although other specimens of this species of pterosaur, Darwinopterus, have been uncovered before, this particular fossil, bought from a farmer in China, provides important information.

“In almost none of the previous collections can we tell what the gender of the fossil is,” said David Unwin, a paleobiologist at the University of Leicester, in England, and one of the study’s authors. “This is the first association of an egg with an adult, so we can identify it as a female.”

The finding, which appears in the journal Science, provides evidence for what scientists had previously hypothesized: that female pterosaurs had larger hips than males and no crest on the skull. Male pterosaurs had large crests.

The study also provides information about how the pterosaurs reproduced. The egg appears to be soft-shelled, more similar to the type of eggs laid by crocodiles than to the hard-shelled eggs laid by birds.

This implies that, like crocodiles and other reptiles, pterosaurs probably buried their eggs in the ground, rather than incubating them by sitting on them, as birds do.

Dr. Unwin said that the fossil has provided a good preliminary picture of pterosaur biology.

“What we now need to do,” he said, “is to look at lots of pterosaurs and look at other things such as size: Were males typically bigger or smaller than females? And other really fundamental kinds of things that we know for living species, we can now look at in pterosaurs.”

NYTimes