Researchers have come across the preserved cranium of an enormous river dolphin from a species that is believed to have escaped the sea and taken shelter in the Amazonian rivers of Peru around 16 million years ago. This extinct species was estimated to be as long as 3.5 meters, making it the biggest river dolphin ever documented.

The recent identification of Pebanista yacuruna as a new species brings attention to the growing dangers faced by the world’s remaining river dolphins. According to the main researcher of a new study published in Science Advances today, Aldo Benites-Palomino, all these dolphins are at risk of extinction within the next 20 to 40 years. Benites-Palomino stated that this species is a member of the Platanistoidea family, which was prevalent in oceans between 24 million and 16 million years ago.

According to him, the river dolphins that managed to survive were the only remaining members of once diverse marine dolphin groups. These dolphins were believed to have transitioned to freshwater rivers in search of different sources of food.

Rivers serve as a release mechanism for the prehistoric remains we discovered, just as they do for all present-day river dolphins.

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In 2018, Benites-Palomino uncovered a fossil in Peru while he was still studying as an undergraduate. Currently, he is pursuing a doctorate in the department of paleontology at the University of Zurich and states that the publication of his research paper was postponed due to the pandemic.

While on a walk with a colleague, the researcher noticed a fossil fragment of a jaw. Upon recognizing it and seeing the teeth sockets, he exclaimed, “This is a dolphin!” Both of them were astounded.

The speaker stated that they eventually discovered the animal was not connected to the pink dolphins of the Amazon river. They had come across a massive creature with its closest living relative located 10,000km away in south-east Asia.

Director of the paleontology department at Zurich University, Marcelo R Sánchez-Villagra, expressed curiosity about the discovery. He stated, “Despite decades of studying South America, we have come across numerous large species from this area, but this is the initial encounter with a dolphin of this type.”

According to Benites-Palomino, the fossil was noteworthy due to its large size and the absence of any connections to present-day river dolphins found in the same area.

River dolphins, including their closest living relatives who reside in the Ganges and Indus rivers, are facing a common issue of potential extinction. According to experts, urban development, pollution, and mining are the main factors contributing to this risk. As a result, the Yangtze river dolphin has already become extinct due to these same causes.

Source: theguardian.com