Researchers at a museum in Nagano Prefecture possess fossils at least 5 million years old belonging to a cetacean species known as right whales, making them the oldest fossilized remains of the mammal in the world, officials said.
The researchers believe the fossilized skull bones and jaw of the right whale on display at Shinshushinmachi Fossil Museum date back 5 million to 6 million years, museum curator Ken Narita said earlier this week.
The oldest right whale fossil previously found was uncovered in Italy and dates back about 4 million years, Narita said.