Long-held assumptions regarding the geographic range of duck-billed dinosaurs have been called into question by the discovery in Chile of the remains of a type of herbivorous dinosaur that was previously unknown in the southern hemisphere. Gonkoken nanoi, a species that could grow to be four metres (13 feet) long and weigh a tonne, inhabited what is now Chilean Patagonia 72 million years ago. "These were slender-looking dinosaurs, which could easily adopt a bipedal and quadrupedal posture to reach the vegetation at height and at ground level," said Alexander Vargas, director of the paleontological network of the University of Chile and one of the authors of the study published by the journal Science Advances and presented in Santiago. The discovery proved that ancient species of hadrosaurs, a type of duck-billed dinosaur prevalent in North America, Asia, and Europe between 145 and 66 million years ago, sought sanctuary in Chilean Patagonia. Their presence in the remote southern lands surprised scientists, who will have to "understand how their ancestors got there," Vargas said. Gonkoken nanoi, the fifth species of dinosaur discovered in Chile, was actually found in 2013, kicking off a decade-long investigation. The name Gonkoken comes from the Tehuelche language, the first inhabitants of the region, and means "similar to a wild duck or a swan."