For a century, scientists wrongly pictured duck-billed dinosaurs wading in swamps
Duck-billed dinosaurs were among the most successful plant-eaters of the Late Cretaceous, grinding their food with stacked batteries of teeth. Yet from the 1850s until 1964, experts insisted they lived half in water, nibbling soft pond weeds. A dinosaur mummy with apparent webbed hands only deepened the mistake.
The name Hadrosauridae means stout lizard, and the family includes familiar genera such as Edmontosaurus and Parasaurolophus. They descended from earlier iguanodontian dinosaurs and dominated herbivore niches in Asia and North America before some lineages spread into Europe, Africa and South America near the end of the Cretaceous. Their flattened snouts give them the duck-bill nickname. Instead of simple teeth, they packed many into dental batteries that worked like grinding plates. Young animals of some species walked mainly on two legs, while adults mostly went on all fours.
Two main branches are recognised. Lambeosaurines carried hollow crests or tubes on their heads; saurolophines, called hadrosaurines in most work before 2010, lacked hollow crests, though some had solid ones, and tended to be bulkier. The family probably arose in North America and soon reached Asia; later, lambeosaurines from Asia colonised the island that is now France and Spain, and one lineage went on into North Africa.
Discovery began with teeth and bones collected near Montana's Judith River between 1854 and 1856, the first dinosaur fossils recognised in North America, which Joseph Leidy named in 1856. In 1858 he described Hadrosaurus foulkii from bones a New Jersey farmer had dug up about twenty years before, and suggested the animal was amphibious. Edward Drinker Cope, who coined the family name in 1869, argued the teeth were too fragile for anything but soft water plants. The idea stuck, reinforced by a remarkably complete Edmontosaurus found in Wyoming in 1908 by Charles Sternberg and his sons, with skin impressions preserved; Henry Osborn called it the dinosaur mummy.
The turning point came in 1964, when John Ostrom examined their climate, companion species, anatomy and fossil stomach contents and concluded they were capable land animals. Interest surged again in the 2000s, and a 2011 symposium at the Royal Tyrrell Museum drew more than fifty presentations, many later collected in a 2015 book.
Source: Hadrosauridae
