Abstract
We calculated water vapor conductance (a product of eggshell porosity) from the first definitively identified sauropod egg (Megaloolithus patagonicus) from the Auca Mahuevo locality in Argentina. We then compared the results with those from M. siruguei (an egg type long associated with sauropod dinosaurs) from the Pinyes locality in Spain. The 14-cm Auca Mahuevo egg has a thinner eggshell and 47 times fewer pores than the 22-cm M. siruguei specimen. The resulting water vapor conductance (