A fossil found last May by a boy in Kuji, Iwate Prefecture, has been confirmed as the toe bone of a Coelurosauria, a carnivorous dinosaur that lived in the latter part of the Cretaceous period around 85 million years ago, a researcher said Friday.

The find is rare. More than 10 fossils linked to carnivorous dinosaurs have been found in Japan, but most were just teeth.

"It is uncommon that a toe bone, which is easily worn away, was found in such good condition," said Ren Hirayama, a Waseda University professor who examined the fossil, which is just 3 cm long and 1 cm in diameter.

Judging from the bone, which came from the left back foot, the dinosaur was probably 1 to 2 meters tall, Hirayama said.

The discoverer was Takato Sasaki, a 13-year-old junior high school student from Aomori Prefecture.

"I first thought it was a small branch, but it was more amazing than that," said the boy, who likes to collect minerals.

Sasaki was visiting the Kuji Amber Museum with his family when he found the fossil at an amber mine site on the premises. Fossils have been found in the past near the museum.

Masateru Shibata, a researcher at the Fukui Prefectural Dinosaur Museum, said the finding "will be significant in studying the evolution and migrations of dinosaurs in Japan."