Saurolophinae

Saurolophinae is one of the two major subfamilies of hadrosaurid dinosaurs, alongside the hollow-crested Lambeosaurinae. It gathers the solid-crested and crestless duck-bills long grouped as the "hadrosaurines," including such genera as Saurolophus, Edmontosaurus, Gryposaurus, Kritosaurus, Brachylophosaurus, and Maiasaura, and is further divided into tribes such as Brachylophosaurini and Kritosaurini. Which name applies depends on where Hadrosaurus falls: Saurolophinae is used for the sister clade of Lambeosaurinae only when Hadrosaurus foulkii lies outside it, and the older Hadrosaurinae when it lies inside (Madzia and colleagues, 2021). Where its members bear cranial ornamentation at all, it takes the form of a solid crest built mainly from the nasal bones rather than the inflated, hollow nasal passages seen in lambeosaurines. Saurolophines were a diverse radiation of the Late Cretaceous, ranging across North America and Asia and reaching South America, where an endemic group of southern kritosaurs is thought to have arrived by island-hopping and rafting around 85 million years ago.