The conservative structure of the ornithopod eggshell: electron backscatter diffraction characterization of Guegoolithus turolensis from the Early Cretaceous of Spain

The Spheroolithidae oospecies Guegoolithus turolensis, putatively attributed to non-hadrosauroid styracosterns was first described in the Barremian of the Iberian Basin, and later reported in the Valanginian–Hauterivian of the Cameros Basin, with both occurrences separated by a few hundred kilometres but by over 10 million years. Here we apply electron backscatter diffraction to search for crystallographic and ultrastructural differences between...