"The findings show there was an ecosystem led by tyrannosaurs in Nagasaki, which was connected to the Asian continent by land at that time," says Kazunori Miyata, the museum's chief researcher. While the teeth were found in the same place, it's not known if they both belonged to one creature, and the specific species hasn't yet been determined. The largest tooth is 8.2cm (3.2in) long, and while the second is damaged, it could have been even bigger when attached to the dinosaur, the museum says.