KOBE (Kyodo) The fossilized teeth of a carnivorous dinosaur believed be an ancestor of the greatest of its kind, the tyrannosaurus, have been found in Tamba, Hyogo Prefecture, museum officials said Saturday.

The dinosaur, whose teeth were exhumed from strata dating back to between 140 million-136 million years ago, may have been about 5 meters long, according to the Museum of Nature and Human Activities in the prefecture.

The teeth are much larger than those of other 1- to 3-meter-long dinosaurs found in similarly old strata in Japan and worldwide, the museum said.

Since the era of the strata is tens of millions of years earlier than the age of the over 10-meter-long tyrannosaurus, the creature was in the course of evolving, it added.

"If the dinosaur belongs to the same era as the strata, the tyrannosaurus could have started to grow larger much earlier than thought," said curator Haruo Saegusa.