During the the Cretaceous, hadrosaurs, the "duck-billed dinosaurs", were common in Eurasia, a continent which produced such monsters as Shantungosaurus.  The Asiatic duckbills were reduced to just two lambeosaurine species after the K-T calamity and, after a brief comeback, were hit again during the Late Eocene. After this time, competition from other ornithischians combined with increasing nest predation from innovative new kinds of mammals and the spread of grasslands pushed these herbivores out of their accustomed niches. At the end of the Oligocene, the last of the old-endemic Asian duckbills died out leaving Eurasia devoid of hadrosaurs. This situation lasted until the Miocene when the livebearing ungulapedes invaded from Africa. A more recent influx of duckbills took place during the Pleistocene when "old-fashioned" North American hadrosaurs migrated across the Bering Land Bridge.
(Text by Daniel Bensen and Brian Choo)
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