Although their fossil remains are infrequently found, pterosaurs were probably the most abundant winged, backboned animals of the dinosaurian era (230 to 65 million years ago).
Pterosaurs were the first group of vertebrate animals to adopt an aerial lifestyle. They had no competition in the air for about 90 million years, until the evolution of birds in the Late Jurassic Period.
Considerable controversy exists over how well these featherless creatures could fly and how they could take off, but the fossil remains of dozens of pterosaurs have been found in marine sediments hundreds of kilometres from what would have been the nearest coast. With huge wings (compared to body size), walking would have been difficult, but pterosaur trackways have been found, and researchers are sorting out how they moved about when not in the air.
The largest pterosaur, Quetzalcoatlus, had a wingspan of up to about 11 m (36 ft.). Quetzalcoatlus was the largest flying creature of all time. The structure of giant pterosaurs suggests that they were adapted to flying in an atmosphere that was denser than it is now.
Pterodaustro guinazui was one of the most peculiar flying reptiles known, thanks to its unusual abundance of teeth. Its lower jaws were lined with hundreds of long slender teeth, about 1000 in total. These were apparently used to filter small crustaceans and other organisms from the water. The upper jaws had blunt, short teeth to crush and chop the small animals trapped by the lower jaws. It probably did not scoop water as it skimmed over the surface, but more likely stood in the shallows to sieve its prey.
Other filter-feeding pterosaurs are known, such as those in the genus Ctenochasma, but Pterodaustro had hundreds more teeth than Ctenochasma and the other pterosaurs that fed in this manner.
Remarkably, Pterodaustro is also one of the best known, because complete skeletons are known from individuals of several life stages, including a spectacularly preserved embryo found inside an egg. The wingspan of Pterodaustro guinazui was about 1.33 m (4.5 ft).
Its scientific name means "southern wing", but Pterodaustro is sometimes called the "flamingo pterosaur", after the large, brightly coloured wading bird that also filter-feeds in shallow waters on plankton and crustaceans. Like the flamingo, Pterodaustro may have had a pink colour due to ingestion of aqueous bacteria and beta carotene from its food supply.
The earliest pterosaurs, found in Italy, were quite small. Fossil remains of the last one known, the giant Quetzalcoatlus, were found in Texas, in terrestrial deposits dating to the very end of the Cretaceous Period. Pterodaustro remains have been excavated in some abundance from 110 to 100 million year-old (Early Cretaceous) freshwater lake deposits in central Argentina and Chile. Ctenochasma fossils have been found in the Late Jurassic deposits of Solnhofen, Germany.