Pterosaurs, like their dinosaur relatives, didn't wait until they were fully grown to have sex, a new study suggests. Researchers examined microscopic tree ring-like growth markings in hundreds of bones from a species of the extinct flying reptiles discovered in central Argentina in the 1990s. The Pterodaustro guiñazui bones came from multiple individuals, including an embryo inside an egg and adults with wingspans between 1 to 8 feet (0.3 to 2.5 meters). P. guiñazui lived during the mid-Cretaceous, about a hundred million years ago. "It is quite amazing that even after millions of years, the microscopic structure of the bone...