|Hundreds of pterosaur bones laying on the surface, demonstrating the richness of these sites. |
Photo: Alexander Kellner (Museu Nacional/UFRJ)
The largest clutch of pterosaurs eggs ever discovered suggests that the extinct flying reptiles may have gathered together in vast colonies to lay their eggs.
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.
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.
The research is published in the journal, Science.