New River Dolphin Found in Brazil

New River Dolphin Found in Brazil

A suspected new river dolphin species has emerged in Brazil, and scientists warn that it is highly endangered.

The scientists in Brazil observed about 120 of the new dolphin’s relative, the Araguaian dolphins over 12 weeks. They estimate that as few as 600 of the animals could live in the entire river basin.

The scientists warn that all river dolphins face many threats, including dam construction, which can cut off the animals from others of their kind, limiting their reproduction opportunities. They are sometimes killed by local fishermen, who fear that they compete with them for fish, and they end up ensnared and killed by fishing gear.

River dolphins are among the rarest, and most endangered, dolphins in the world. Three of the four known species are listed as "threatened" by the International Union for Conservation of Nature (IUCN).

Scientists in Manaus, Brazil, announced the existence of the proposed new species of river dolphin. Discovered in the Araguaia River Basin in central Brazil, the animals were isolated from other dolphins in the adjacent Amazon Basin to the west by a series of rapids and a small canal. As a result, the scientists suggest calling the new species the Araguaian dolphin, or Inia araguaiaensis.

In the study, the Brazilian team concluded that the DNA of the Araguaian river dolphins is sufficiently different from that of other dolphins to warrant designation as a new species. The degree of difference suggests that the Araguaian dolphin most likely separated from other dolphin species more than two million years ago. Physical and genetic differences from other dolphins, they write, represent "strong evidence that individuals from the Araguaia River represent a distinct biological group." 

The newly proposed species marks the first new discovery of a true river dolphin since 1918, when researchers identified Lipotes vexillifer, the Yangtze River dolphin or baiji, in China. The baiji was declared "functionally extinct" in 2006 after scientists failed to find even one individual.