The Amazon’s Biggest Freshwater Dolphin Species Now Extinct

The Amazon basin was once home to freshwater dolphins that grew up to 3.5 meters long, making them the largest river dolphin known to science.

Researchers say they made this surprising discovery during a 2018 expedition to Peru Aldo Benitez Palomino at the University of Zurich, Switzerland. When the research team saw the animal's fossilized skull sticking out of the river bank, they immediately knew it was a dolphin. Closer analysis confirms that this giant skull is unlike anything previously discovered.

Researchers named this new species Pebanista Yacluna. The name pays homage to the mythical aquatic people, Yacuruna, who are believed to live in underwater cities in the Amazon basin.

The 16 million-year-old fossils were unearthed in an area that was once covered by a “very large lake, almost like a small ocean in the middle of a jungle,” Benitez Palomino said. He says, based on the small eye sockets and large teeth of ancient dolphins. P. Yacluna It was probably a predator with poor eyesight. They relied heavily on echolocation to find fish. “We realized that it was really living in muddy water because its eyes started to get smaller,” Benitez-Palomino said.

Because the fossil was found in the Amazon basin, researchers expected the fossil's closest living relative to be the modern Amazon river dolphin.Instead, they found P. Yacluna It was more closely related to the river dolphin of South Asia. Like them, this ancient species also has a raised crest on its skull that enhances its echolocation abilities.

P. Yacluna Benitez-Palomino said it may have been driven to extinction amid broader ecological changes. “About 11 to 12 million years ago, this huge wetland system began to drain, making way for what is now the Amazon. At that moment, many species became extinct, which is why this giant dolphin Maybe it was fate.”