A team of researchers identified a new genus and species of river dolphins thanks to the discovery of an ancient fossil in 2011.

According to The Washington Post, Nick Pyenson, a paleobiologist at the Smithsonian's National Museum of Natural History in Washington D.C., discovered the fossil of what he thought was a shark-toothed dolphin off the coast of Panama four years ago.

Published in the journal PeerJ, Pyenson and his colleagues detailed Isthminia panamensis as a close in appearance to Amazon river dolphin, but with the ability to live in the open ocean.

"We discovered this new fossil in marine rocks, and many of the features of its skull and jaws point to it having been a marine inhabitant, like modern oceanic dolphins," Pyenson, the study's lead author, said in a press release. "Many other iconic freshwater species in the Amazon, such as manatees, turtles and stingrays have marine ancestors, but until now, the fossil record of river dolphins in this basin has not revealed much about their marine ancestry. Isthminia now gives us a clear boundary in geologic time for understanding when this lineage invaded Amazonia."

Pyenson told The Post the researchers think the dolphin they discovered "lived in the channel that connected the Atlantic and Pacific oceans before the isthmus of Panama formed."

"My hope is that by reviewing deep evolutionary evidence about river dolphins, we can guess what their, and maybe our, future will be," he said.

Having this study may come in handy in case sea levels continue to rise the way they have and are projected to. The study indicated the dolphin moved to the channel due to increased sea levels.

"Isthminia is actually the closest relative of the living Amazon river dolphin," study co-author Aaron O'Dea, staff scientist at the Smithsonian Tropical Research Institute in Panama, said in the release. "While whales and dolphins long ago evolved from terrestrial ancestors to fully marine mammals, river dolphins represent a reverse movement by returning inland to freshwater ecosystems. As such, fossil specimens may tell stories not just of the evolution these aquatic animals, but also of the changing geographies and ecosystems of the past."