Researchers have unearthed the preserved head of an enormous river dolphin, believed to have migrated from the sea to take shelter in Peru’s Amazonian waterways approximately 16 million years ago. This now-extinct type of dolphin would have reached lengths of up to 3.5 meters, earning the title of the biggest river dolphin ever documented.
Aldo Benites-Palomino, the lead author of a study published in Science Advances, explains that the recent identification of a new species, Pebanista yacuruna, brings attention to the pressing dangers faced by river dolphins worldwide. These dolphins, belonging to the Platanistoidea family, are at risk of extinction within the next 20 to 40 years, similar to other species in this group that lived in oceans between 24 million and 16 million years ago.
According to him, the current population of river dolphins are the only remaining members of a previously diverse group of marine dolphins. It is believed that these dolphins migrated from the ocean to freshwater rivers in search of nourishment.
“Rivers serve as a release mechanism for the prehistoric fossil that was discovered, and this holds true for all contemporary river dolphins.”
In 2018, Benites-Palomino discovered a fossil in Peru while he was still a college student. He is currently pursuing a doctorate in paleontology at the University of Zurich and mentions that the pandemic has caused a delay in the research paper.
While on a walk with a colleague, he came across a portion of a fossil that appeared to be a fragment of a jawbone. As soon as he identified it, he noticed the sockets for teeth and exclaimed, “This is a dolphin!” Both of them were in disbelief.
“We soon discovered that it was not connected to the pink Amazon river dolphin,” he explained. “We had come across a massive animal with its closest living relative living 10,000km away in south-east Asia.”
According to Marcelo R Sánchez-Villagra, who is in charge of the paleontology department at Zurich University, the discovery is quite fascinating. He mentioned that although they had come across numerous large species in South America over the course of 20 years, this particular dolphin is unique.
According to Benites-Palomino, the fossil was noteworthy due to its large size and lack of connection to modern river dolphins found in its previous habitat.
One major issue that affects river dolphins, as well as their closest living relatives in the Ganges and Indus rivers, is the threat of extinction. According to the source, the main reasons for this are urban development, pollution, and mining, which have already led to the extinction of the Yangtze river dolphin.
Source: theguardian.com
