Blasisaurus is a genus of lambeosaurine hadrosaurid dinosaur from the Late Cretaceous. It is known from a partial skull and skeleton found in late Maastrichtian-age rocks of Spain.[1] The type species is Blasisaurus canudoi, described in 2010 by Penélope Cruzado-Caballero, Xabier Pereda-Suberbiola and José Ignacio Ruiz-Omeñaca, a group of researchers from Spain.
The generic name refers to the Blasi 1 site where the fossil was found. The specific epithet honours paleontologist José Ignacio Canudo.[1] The holotype, MPZ99/667, is housed in Huesca. It was found in a layer of the Arén Formation dating from the upper Maastrichtian, about 66 million years ago.[1] It consists of a skull with fragmentary lower jaws.[1]
Blasisaurus was a medium-sized ornithopod. Its describers identified two distinct features: the cheekbone has a rear projection with a hook-shaped upper edge and the lower sleep window is narrow and D-shaped.[1] From the same formation is Arenysaurus, a related species. They are distinguished by the shape of the teeth and missing secondary ridges. Blasisaurus also differs from Koutalisaurus by a downward bent front edge of the lower jaw.[1]
Blasisaurus discoverers performed an exact cladistic analysis to determine its phylogenetic position, which placed it as the sister taxon to Arenysaurus.[1] Together they form a tribe, the Arenysaurini, that is more derived than Tsintaosaurus and Jaxartosaurus.[1] Blasisaurus confirmed the hypothesis that, in the Late Cretaceous, different hadrosaurids from Asia and Europe migrated across land bridges.[1] Where in Lambeosaurinae Blasisaurus and Arenysaurus belong is disputed. Some put them in the tribe Lambeosaurini[2] at the base of the lambeosaurin-parasaurolophin split,[1] some in Parasaurolophini.[3] Below is the most recent cladogram including Blasisaurus and Arenysaurus, published by Penélope Cruzado-Caballero et al. in 2013:[3]