Remains of extinct giant river dolphin found in Amazon region, researchers say

March 20 (UPI) -- An international team of researchers found the remains of a giant freshwater dolphin that is about 16 million years old and the largest river dolphin species ever found, the University of Zurich announced Wednesday.

The newly discovered species is named Pebanista yacuruna after a mythical group of aquatic people thought by some to have inhabited the Amazon basin long ago.

"After two decades of work in South America, we had found several giant forms from the region, but this is the first dolphin of its kind," Marcelo Sanchez-Villagra, director of the paleontology department at the University of Zurich said.

Researchers discovered the dolphin's remains in the Peruvian Amazon area and say it measured between 10 feet to 11.5 feet in length with a long, toothy snout for catching and eating prey.

They said the newly discovered but extinct species was part of the Platanistoidea group of dolphins that existed between 24 million and 16 million years ago and likely was an ocean-going species that entered the Amazon region due to its abundance of food sources.

"The Peruvian Amazonia looked very different from what it is today [when] much of the Amazonian plain was covered by a large system of lakes and swamps ... stretching across what is today Colombia, Ecuador, Bolivia, Peru and Brazil," said lead researcher Aldo Benites-Palomino of the University of Zurich's paleontology department.

The giant dolphins thrived in the area until about 10 million years ago, when the modern Amazon River began to emerge from the extensive aquatic environment and deprived the giant dolphins of their habitat and food sources.

The researchers said they expected to find close relatives of the current Amazon river dolphins but, the Pebanista yacuruna are cousins of river dolphins found in South Asia.

Finding fossils in the Amazon rainforest only is possible during the dry season when the river levels are low enough to reveal fossil-bearing rocks that could be swept away by rising waters and lost forever.