An international team of paleontologists, led by scientists from CONICET (Argentina's National Scientific and Technical Research Council), has just published a study that revolutionizes our understanding of Gondwanan dinosaurs. The research focuses on the nearly complete skull of a Gasparinisaura cincosaltensis, a small ornithopod that inhabited Patagonia approximately 83 million years ago, during the Late Cretaceous (Campanian stage).
The fossil, known as holotype MUCPv 208, was discovered in the Anacleto Formation, near Cinco Saltos, Río Negro province. It is the third best-preserved skull of its group worldwide and the only one from a non-hadrosauriform ornithopod in the southern hemisphere. The analysis, performed using medical computed microtomography (µCT), allowed researchers to create a 3D model without damaging the fossil and study its internal deformations.
A Skull That Changes History
The study, published in the scientific journal Cretaceous Research, reveals that Gasparinisaura belongs to the Elasmaria lineage, within the family Dryosauridae. But the most striking finding is the definition of a new subfamily of Gondwanan dinosaurs: Dysalotosaurinae.
This subfamily includes Dysalotosaurus lettowvorbecki (Late Jurassic of Tanzania) and Leaellynasaura amicagraphica (Middle Cretaceous of Australia). The new classification is based on unique anatomical features, such as the separation between one of the internal walls of the head and the roof of the skull.
Enormous Eyes: An Adaptation to Darkness?
One of the most surprising discoveries is that the enormous eyes of Gasparinisaura were a characteristic of adults, not juveniles. The size of the eye sockets modified the shape of the skull bones, shifting them backward and elevating the snout bones.
This great visual capacity, supported by previous studies of L. amicagraphica, would explain the success of dysalotosaurines in high latitudes, where periods of darkness could last for months. Acute vision allowed them to find food and navigate in low-light conditions.
An International Team and a Tribute
The research was carried out by an international team with participation from the Institute for Research in Paleobiology and Geology (IIPG, CONICET-UNRN) in General Roca, the Institute for Biodiversity and Environment Research (INIBIOMA, CONICET-UNCOMA) in Bariloche, the Bariloche Paleontological Museum, the University of La Laguna (Spain), and the Aragosaurus-IUCA Team at the University of Zaragoza.
Key researchers include Paul-Emile Dieudonné (CONICET, IIPG), Ariana Paulina-Carabajal (CONICET, INIBIOMA), and Penélope Cruzado-Caballero (University of La Laguna). The work pays posthumous tribute to paleontologist Jorge Calvo, who passed away in 2023 and was director of the Lago Barreales Paleontological Center (Neuquén).
This discovery not only expands knowledge about the diversity of Patagonian dinosaurs but also demonstrates how evolution can adapt species to extreme environments—a legacy that continues to astonish science.