Researchers have reported the discovery of hundreds of prehistoric eggs in China that were laid by pterosaurs, the world's first flying vertebrates that appeared before the birds and bats.
The winged reptiles were fearsome-looking creatures that thrived with the dinosaurs during the Lower Cretaceous period. This species is believed to have a wingspan measuring up to 13 feet and likely fed on fish using their large and teeth-filled jaws.
Scientists have been studying these prehistoric creatures for over 200 years but their eggs were only discovered in the early 2000s. Now, researchers find themselves lucky to find a cache of hundreds of well-preserved eggs of the pterosaur species called Hamipterus tianshanensis.
In a study published in the journal Science, Chinese Academy of Sciences researchers reported finding at least 215 well-preserved eggs in one sandstone block. Most of these eggs kept their shape over a long period of time and 16 still have embryonic remains.
Study Of Pterosaur Eggs Sheds Light On Development Of Prehistoric Flying Reptiles
Analysis of the eggs using osteohistology, computed tomography scanning and micropreparation showed that in some potentially late-term embryos, the bones lack extensive ossification, which suggests that the hatchlings may have been flightless and less precocious than previously believed. The embryonic bones showed that the hind legs of the baby Hamipterus developed faster than crucial wing elements such the humerus bones.
"Our conclusion is that a baby Hamipterus can walk but can't fly," said study coauthor Shunxing Jiang, from the Chinese Academy of Sciences.
Lived In A Colony Near A Lake
Jiang and colleagues think that the prehistoric reptile lived in a bustling colony near a freshwater lake. The females gathered together when they lay their eggs in nesting colonies and returned over the years to the same nesting site.
"The geological context, including at least four levels with embryos and eggs, indicates that this deposit was formed by a rare combination of events, with storms acting on a nesting ground," researchers reported in their study. "This discovery supports colonial nesting behavior and potential nesting site fidelity in the Pterosauria."
Researchers think that the eggs, some juveniles, and adult individuals were washed away from a nesting site during a storm and into the lake where these were preserved and then fossilized.
''The work is a crucial advance in understanding pterosaur reproduction,'' said Charles Deeming, from the University of Lincoln. ''Hopefully additional finds of equally spectacular fossils will help us answer such questions for pterosaurs and allow us to paint an increasingly complete picture of reproduction in these extinct species.''