Scientists confirm fossils discovered 17 years ago in Japan belong to hitherto unknown dinosaur

© Masato Hattori
An artist’s rendering of Yamatosaurus, left, and Kamuysaurus, which is believed to have lived in Hokkaido.

Dinosaur fossils discovered on Awaji Island in Hyogo Prefecture 17 years ago have been confirmed as belonging to a new species of herbivorous dinosaurs, according to a group of scientists from Hokkaido University; the Museum of Nature and Human Activities, Hyogo; and other academic organizations.

The group decided the scientific name of the dinosaur would be “Yamatosaurus izanagii,” a reference to a Japanese creation myth in which the island was the first Japanese terrain created.

This is the ninth time a new dinosaur species discovered in the country has been given a scientific name. A paper about the dinosaur was published in a British science journal on Wednesday.

The fossils were discovered in 2004 by amateur fossil enthusiast Shingo Kishimoto, 72, from Himeji in the prefecture, among others. In the city of Sumoto on the island, they excavated 23 pieces of fossils, including part of the dinosaur’s lower jaw measuring about 50 centimeters long and about 20 centimeters tall, from a late Cretaceous stratum formed about 72 million years ago.

The fossils were analyzed in detail by Prof. Yoshitsugu Kobayashi of Hokkaido University and other researchers. They were convinced that the tooth alignment and dentary bones of the fossils showed unique characteristics not found in the fossils of other herbivorous dinosaurs from the same period. The scientists came to the conclusion that the dinosaur was a new species belonging to the Hadrosauridae family.

The Yomiuri Shimbun
A fossil of the lower jaw of Yamatosaurus, which was discovered on Awaji Island in Hyogo Prefecture in 2004

The dinosaur is believed to have been bipedal with a body length of about 7 to 8 meters, weighing about 4 to 5 tons.

“This is an important specimen to shed light on the evolution of herbivorous dinosaurs in East Asia,” said Yoichi Azuma, an honorary professor of Fukui Prefectural University.

Fossils of Kamuysaurus, which also belongs to the hadrosaurids, were also excavated from a stratum of the same period in Hokkaido.