Armored Dinosaur Tooth Fossil on Nagasaki Peninsula

A fossil believed to be a tooth of an armored dinosaur (Thyreophora - Ankylosauria) was found in the 81-million-year-old (Late Cretaceous) Mitsuse Formation on the west coast of the Nagasaki Peninsula in Nagasaki City. This was a joint investigation by the Fukui Prefectural Dinosaur Museum and the Nagasaki City Board of Education.

The tooth fossil, 9.8 mm wide and 9 mm high, had the large cusps characteristic of Ankylosauria teeth.
Although identifying the species is difficult, it is estimated to have been 5-8 meters in total length.

About 20 species of Ankylosauria have been reported in Asia to date.
In Japan, Ankylosauria fossils have been found in Yubari, Hokkaido, and Mifune Town, Kumamoto Prefecture.

Teeth believed to be from a small carnivorous dinosaur (theropod) and a femur from a hadrosaurid (ornithopod) have also been found in the same formation, suggesting that the Nagasaki Peninsula may have been home to a diverse range of dinosaurs during the Late Cretaceous.