Japanese scientists say they have identified a new species of whale — a remarkable discovery if confirmed.

The animal is a type of baleen, the family of whales that strain tiny plankton and other food from seawater, the researchers say.

“Can you imagine? An animal of more than 10 meters was unknown to us even in the 21st century,” said Tadasu Yamada of Tokyo’s National Science Museum, the senior author of the study that appears in this week’s issue of the journal Nature.

Most baleens grow to enormous proportions, like the blue whale, which at 75 feet long and more than 100 tons is believed to be the largest animal that has ever lived.

By comparison, the new species is on the small side, about 30 feet long — about the size of a motor home — and slender.

While new species of smaller creatures such as insects, birds and amphibians are discovered every year, it is very unusual for scientists to identify a new mammal, particularly one so large. Most whale species were described during the 18th and 19th centuries when commercial whaling drove many to the brink of extinction.

Scientists currently recognize 70 whale species, including as many as 12 types of baleen whales. But little is known about the subtle differences among many types of whales that are seldom seen by humans.

The Japanese researchers made their discovery through DNA analysis of nine adult whale carcasses. It could take additional studies over several years before other biologists accept the new whale species.

According to the Nature study, the new species shows several differences from fin whales, including external features, bone structure and DNA. The researchers named the new species Balaenoptera omurai in honor of the late Japanese whale researcher, Dr. Hideo Omura.