The first new river dolphin species in almost 100 years has been discovered in Brazil.
Scientists have named the new breed - only the fifth known of its kind in the world - 'Araguaia', after the river where it was found.
Writing in the journal Plos One, researchers claim it evolved from other South American river dolphin species more than TWO MILLION years ago.
There are thought to be 1,000 of the rare creatures alive.
Experts say there there are only four known species of river dolphin, and three of them are on the 'Red List', meaning they are critically endangered.
These dolphins are distant relations to sea-dwelling dolphins - and have long beaks which let them hunt for fish in the mud at the bottom of rivers.
They are the first new species to be discovered since 1918.
One of the best known species, the Yangtze river dolphin or baiji is believed to have gone extinct in about 2006.
South America though is home to the Amazon river dolphin, also known as the pink dolphin or boto, said to be the most intelligent of all the river species.
Lead author Dr Tomas Hrbek, from the Federal University of Amazonas, said: ""It was something that was very unexpected, it is an area where people see them all the time, they are a large mammal, the thing is nobody really looked. It is very exciting."
The scientists say there are some differences in the number of teeth and they suspect the Araguaia river species is smaller, but most of the clues to their separate nature were found in their genes.