National / Science & Health

Scientists unveil Japan's largest dinosaur yet, a herbivore that lumbered along coasts of Hokkaido


Japanese scientists have identified a new species of dinosaur from a nearly complete skeleton that was the largest ever discovered in the country, measuring eight meters long.

After analyzing hundreds of bones dating back 72 million years, the team led by Hokkaido University concluded the skeleton once belonged to a new species of hadrosaurid dinosaur, a herbivorous beast that roamed the Earth in the late Cretaceous period.

A partial tail was first found in Mukawa, Hokkaido, in 2003 and later excavations revealed the entire skeleton. It was classified into the Hadrosaurus herbivorous dinosaur family in 2013.

In an article published Friday in the British journal Scientific Reports, the team made up researchers from Hokkaido University and other institutions said that it has given the dinosaur, called mukawaryu in Japanese, the scientific name Kamuysaurus japonicus, which means Japanese dragon god.

It is the eighth new dinosaur species found in Japan that has been given a scientific name.

Its scientific name is “appropriate for a dinosaur discovered in Hokkaido,” said team leader Yoshitsugu Kobayashi, noting that the word “kamuy” in kamuysaurus means “god” in the language of the prefecture’s indigenous Ainu people.

They believe the dinosaur was a nine-year-old adult and would have weighed either 4 tons or 5.3 tons — depending on whether it walked on two legs or four.

“The fact a new dinosaur was discovered in Japan means there was once an independent world of dinosaurs in Japan or in East Asia, and an independent evolution process,” Kobayashi said.

Kamuysaurus japonicus probably lived in coastal areas, a rare habitat for dinosaurs at that time, and the fossils also provide valuable insights into their environment.

The research raises the possibility that some species of dinosaurs “preferred to inhabit areas near the ocean, suggesting the coastline environment was an important factor in the diversification” of the dinosaurs in their early evolution, the university said.

“I found only part of the skeleton,” said Mukawa resident Yoshiyuki Horita, 69, who discovered the skeleton. “It is Kobayashi’s conviction that has brought us this far.”

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