ornithopods, the elasmarians. See also Timeline of hadrosaur research Alamosaurus – a titanosaur whose ancestors may have crossed into North America at the same time the ancestors of Secernosaurus crossed into South America Huallasaurus Kritosaurus References Saurolophines Maastrichtian life Late Cretaceous dinosaurs of South America Cretaceous Argentina Fossils of Argentina Los Alamitos Formation Golfo San Jorge Basin Fossil taxa described in 1979 Ornithischian genera