Not all dolphins stay in the salty ocean. While uncommon, some river dolphins stay and eat in freshwater and are greatest identified for his or her sweet coloured hues. Now, paleontologists have uncovered a fossilized skull belonging to a 16-million-year-old extinct river dolphin species in Peru named Pebanista yacuruna. It may develop to about 10 to 11 toes lengthy and is the biggest identified species of river dolphin identified to science. Pebanista is described in a research printed March 20 in the journal Science Advances.
The title Pebanista yacuruna is impressed by the Yacuruna, a legendary aquatic those who legends say inhabit underwater cities in the Amazon basin and are just like the god Neptune in Greek mythology. The fossilized skull was discovered in the Peruvian Amazon and belongs to the group Platanistoidea. This group was a typical animal in the Earth’s ocean between 24 and 16 million years in the past. The workforce believes that their primarily salt water dwelling ancestors invaded the prey-rich freshwater ecosystems of the early Amazon and discovered to adapt to this new surroundings.
“Sixteen million years ago, the Peruvian Amazonia looked very different from what it is today,” Aldo Benites-Palomino, a research co-author and paleontologist on the University of Zurich in Switzerland, mentioned in an announcement. “Much of the Amazonian plain was covered by a large system of lakes and swamps called Pebas.”
[Related: Eavesdropping on pink river dolphins could help save them.]
This panorama stretched throughout current day Colombia, Ecuador, Bolivia, Peru, and Brazil and included quite a lot of ecosystems in its lakes and swamps. About 10 million years in the past, the Pebas system started to provide technique to the floodplain that Amazonia appears like right this moment. Pebanista’s prey started to vanish because the panorama started to alter, driving these big dolphins to extinction. With Pebanista out of the image, the family of right this moment’s Amazon river dolphins referred to as Inia had a possibility to sneak in.
While these pink dolphins might look just like the extinct Pebanista, they aren’t straight associated. Pebanista’s closest residing family of this newly found species are literally discovered in South Asia.
“We discovered that its size is not the only remarkable aspect,” says Benites-Palomino. “With this fossil record unearthed in the Amazon, we expected to find close relatives of the living Amazon River dolphin–but instead the closest cousins of Pebanista are the South Asian river dolphins (genus Platanista).”
Both Pebanista and Platanista have extremely developed facial crests that assist them with echolocation. That is once they emit high-frequency sounds and hearken to their echoes in order to “see” their prey by means of sounds.
“For river dolphins, echolocation, or biosonar, is even more critical as the waters they inhabit are extremely muddy, which impedes their vision,” research co-author and University of Zurich paleontologist Gabriel Aguirre-Fernández mentioned in an announcement.
[Related: This dolphin ancestor looked like a cross between Flipper and Moby Dick.]
Pebanista’s elongated snout with many enamel means that it ate up fish the way in which different river dolphins do. Modern Amazon river dolphins referred to as boto are thought of critically endangered and their major threats embody habitat loss and degradation and getting entangled in fishing gear.
The Amazon rainforest stays a really tough place for paleontological fieldwork. Fossils like these are solely accessible in the course of the dry season, when water ranges drop low sufficient to reveal historical layers of bedrock. If the fossils usually are not collected in time, they are often swept away in the course of the wet season.
The specimen was discovered in 2018 in an expedition led by Peruvian paleontologist Rodolfo Salas-Gismondi, who accomplished his postdoctoral work on the University of Zurich. The workforce traveled greater than 180 miles of the Napo River in northeastern Peru and picked up dozens of different fossils. The dolphin skull is now housed on the Museo de Historia Natural in Lima.