Scientists discovered the fossils of an ancient “river” dolphin species which used to swim in the ocean. Moreover, those who dug for the fossils were Smithsonian scientists.
They conducted the excavation in Panama. The fossil was brought back to the National Museum of Natural History. It turned out to be a new species of ancient dolphin, which would swim in the Earth’s waters 6 million years ago.
The new dolphin species was scientifically named Isthminia panamensis. This particular species, which actually lived in the ocean, would resemble modern river dolphins, according to the research team. There are currently four species of river dolphins, which have been labeled as endangered. Moreover, the Chinese river dolphin might have become extinct.
Scientists said that the species followed an evolutionary path, as they started exhibiting paddle-like flippers, long snouts and flexible necks which made them properly adapt to river waters.
Whales and dolphins initially evolved from mammals that would live on land, but they did become amphibious approximately 50 million years ago, when they started migrating to the ocean. After millions of years passed, river dolphins came back to their initial ecosystem.
So, Isthminia panamensis was the ocean-bound ancestor of river dolphins, as the area where it was found suggested it lived indeed in the ocean, even though its features are correlated with modern river dolphins. Scientists claim the newly-discovered species may be a cousin of the river dolphin.
Nicholas D. Pyenson, leader of the study and curator of fossil marine mammals at the Smithsonian’s National Museum of Natural History, stated that this new species was discovered among marine rocks
“and many of the features of its skull and jaws point to it having been a marine inhabitant, like modern oceanic dolphins.”
Moreover, a staff scientist at the Smithsonian Tropical Research Institute in Panama, Aaron O’Dea reported to the press that while whales and dolphin became marine mammals, river dolphins were the species which returned to freshwater, therefore, it was a reverse movement.
Pyenson’s research team assumed that river dolphins invaded the Amazon river approximately 6 million years ago, and this feature could provide clues to how modern animals adapt in different ecosystems.
Photo Credits sciencecodex.com