This video says about itself:
30 November 2017
They were known to rule the skies in the Jurassic and Cretaceous periods, but it seems that pterosaurs had a slow start in life. A new study has revealed that the giant reptiles had a two year incubation and couldn’t fly when they hatched. The findings suggest that young pterosaurs were ‘less precocious than previously assumed.’ The researchers analysed 215 eggs of the pterosaur species Hamipterus tianshanensis found in China.
Hundreds of fossilized eggs shed light on pterosaur development
November 30, 2017
An invaluable collection of more than 200 eggs is providing new insights into the development and nesting habits of pterosaurs.
To date, only a small handful of pterosaur eggs with a well-preserved 3-D structure and embryo inside have been found and analyzed — three eggs from Argentina and five from China. This sparse sample size was dramatically increased upon the discovery of 215 eggs of the pterosaur species Hamipterus tianshanensis from a Lower Cretaceous site in China.
Xiaolin Wang et al. used computed tomography scanning to peer inside the eggs, 16 of which contain embryonic remains of varying intactness. The most complete embryo contains a partial wing and cranial bones, including a complete lower jaw. The samples of thigh bones that remain intact are well-developed, suggesting that the species benefited from functional hind legs shortly after hatching.
However, the structure supporting the pectoral muscle appears to be underdeveloped during the embryonic stage, suggesting that newborns were likely not able to fly. Therefore, the authors propose that newborns likely needed some parental care. Based on growth marks, the team estimates one of the individuals to be at least 2 years old and still growing at the time of its death, supporting the growing body of evidence that pterosaurs had long incubation periods.
Lastly, the fact that a single collection of embryos exhibits a range of developmental stages hints that pterosaurs participated in colonial nesting behavior, the authors say. Denis Deeming discusses these findings in a related Perspective.
Romania now gets its third pterosaur from the Haţeg Basin region of Transylvania, an area known for its rich vertebrate fossil deposits. Though the researchers did not give the poor guy a name, it joins the giraffe-sized Hatzegopteryx and the smaller but by no means diminutive Eurazhdarcho: here.