The taxonomically (titanosaurid) identified eggs and eggshells of Auca Mahuevo (Patagonia, Argentina) provide an opportunity to compare and identify orphan megaloolithid eggs found elsewhere. Previous investigation determined that the oological material from Neuquén (Megaloolithus patagonicus) and Peru (M. pseudomamillare) are related to titanosaurid dinosaurs. Examination of an egg and several (megaloolithid) eggshell fragments from the Upper Cretaceous Marilia Formation strongly suggests, as oological characters are at least genus specific, that the same group of titanosaur dinosaurs, which lived in the Neuquén Basin during the Late Campanian, were also present and reproducing in the Cretaceous Bauru Basin (Brazil). Furthermore, it has been suggested that these titanosaurs, based on the site of Auca Mahuevo, demonstrated colonial nesting and nesting fidelity. These reproductive behaviors would advocate that similar nesting sites should exist in the Upper Cretaceous formations of the Bauru Basin and remain to be discovered, as the present Peiropolis locality represents a secondary deposit where fossils have been transported by high-energy fluvial system.
titanosaurid eggs; Bauru Basin; Auca Mahuevo; eggshell structure; dinosaur paleobiology
