Lime – A 16-million-year-old skull found deep in the Peruvian Amazon revealed that The largest river dolphin in history was more than 3 meters long and inhabited this area that, barely explored, awaits mysteries of reptiles and giant mammals.
The fossil, which is in Natural History Museum of the National University of San Marcos in Limawas found in an exploration carried out in 2018 by a group of researchers in the Napo River, close to the Amazon border with Ecuador.
“We have estimated a body size of 3 to 3.5 meters long, making it the largest river dolphin that has been documented to date.“, the paleontologist and head of the expedition, Rodolfo Salas, explained to EFE.
In addition to the mammal's skull, A Spanish citizen accidentally found a fragment of the jaw of this species at a market in the Amazonian city of Satipo, which he donated to the museum. and which shows that the aforementioned dolphin called 'pebanista yakuruna' measured 13 to 15 feet long.
“This animal could have grown larger and that is very interesting because the size is a reflection of the amount of resources that were available at the time and the size of the habitat in which it lived,” he noted, adding that millions of years ago the Amazon may have been an even richer place.
According to the shape and composition of the fossil, it is known that this species fed on enormous fish..
“Due to its long, thin but very robust snout and its very robust conical teeth, we think that it fed on armored fish. In the Amazon at that time, just as today, there were many species of catfish, also carachamas, which are armored fish that are typical of the area.”Salas added.
The period to which this new dolphin belongs is defined by the paleontologist as “a key moment in the history of the planet” because there was a climatic optimum in which temperatures were very high and similar to those that will be reached on Earth in a few hundred years“so it was important to know what the fauna was like at that time.”
Amazing expedition
“Our surprise was that Instead of finding fossil crocodiles, which was what we were looking for, we found dolphin skulls and one of them, the largest we found, is the 'pebanista yakuruna', an animal that is not related to the Amazon pink dolphin, but to the platanista, a dolphin that currently lives in the rivers of India,” explained Salas. .
Salas, professor of the Cayetano Heredia Universityargued alongside the fossil that they hoped it could be related to the Amazon pink dolphinbut upon studying and analyzing its anatomy they saw that it had rostral ridges on its face that are only present in the platanista that inhabits the Asian continent.
“We know that the platanista and the pebanista were probably distributed throughout the ocean. Then, they ventured into river environments in both the Amazon and India. And this is how these two closely related animals were living in very distant areas,” he indicated, adding that these studies have been carried out by the Peruvian paleontologist Aldo Benítez, who is training in Switzerland.
During this 2018 expedition in the depths of the Loreto department they were able to collect many animal and plant fossils.and assured that in the coming months numerous publications will emerge about these findings.
Expectant future
Salas maintains that This remote area of the Napo River had only been explored by a fellow French geologist, who told him about the possibilities of finding interesting fossils.so, after six years, the paleontologist will return again in August to continue discovering its secrets.
Furthermore, it indicates that The Amazon River erodes the banks a lot and, if it does not leave constantly, the fossils that appear on the surface will be carried away by the current. and the next year they are at the bottom.
“We can never fully know what we may find this time. We didn't know a dolphin of this size or these characteristics existed and look what we found, so we could find a land crocodile that we know lived at that timeit could be some other form of dolphin or some crocodiles that we have not yet documented or mammals,” he concluded, stating that it is fascinating to think about everything that is waiting to be discovered.