It is distinguished by the absence of a characteristic hadrosaur head crest. Scientists from Japan and the United States believe that this discovery forces us to reconsider the ideas about the migration of duck-billed dinosaurs, which did not move from North America to Asia, but vice versa.
Hadrosaurs are the most common type of dinosaur. They had flattened snouts, were herbivorous, and lived more than 65 million years ago. These animals are well adapted to chewing plant food: they had many small and closely spaced teeth, which eventually wore out and fell out, replaced by new ones.
Fossilized remains of duck-billed dinosaurs are found almost all over the world: in Asia, Europe, Africa and North America. A new species of hadrosaur, whose bones were discovered in 2004 in the Kita-ama formation in southern Japan, was named Yamatosaurus izanagii. Scientists from the University of Hokkaido (Japan) and Southern Methodist University (USA) have studied these remains only now.
So it was possible to discover a new species of hadrosaur that lived on the territory of modern Japan 71-72 million years ago, when it was part of the east coast of Asia. Thus, the Japanese islands were connected to the mainland at that time. Scientists have found that these dinosaurs crossed into modern-day Alaska using the Beringian Bridge, once connecting Eurasia and North America.
To make such journeys, Yamatosaurus izanagii even developed shoulder and forelimbs, which helped to transition from bipedal walking to quadrupedal walking. In addition, the lizard did not have a characteristic hadrosaur crest (or it was very small). Yamatosaurus, according to scientists, is the first type of dinosaur from the Late Cretaceous period to be discovered in Japan.
The article is published in the journal Scientific Reports
Image-Reconstruction of Yamatosaurus © Masato Hattori
Source: naked-science.ru, sci-dig.ru