Scientists have recently discovered a new dolphin species that lived 25 million years ago.
The species is said to be extinct. Scientists were able to describe the animal using re-examination of the specimen locked up in a museum collection since 1951.
They believe that this species is closely related to the endangered South Asian river dolphin, and it may offer clues to the evolution of the modern species.
The discovered fossil was a partial skull about 22 cm long, and was found in southeastern Alaska by geologist Donald J. Miller.
Since then, it belonged to the decades-old collection of the Smithsonian Museum of Natural History in Washington DC.
After their analysis, they found that the dolphin swam in the sub-arctic marine waters 25 million years ago. Study authors Nicholas Pyenson and Alexandra Boersma named the species Arktocara yakataga.
Based on the nearby rocks on the fossil, Arktocara may have lived in the late Oligocene epoch. They compared the skull of the dolphin to all other species, living or extinct, and found that it is somehow related to the South Asian river dolphin Platanista – which is the last surviving species of the once-populated group.
Furthermore, the skull confirmed the theory that Platanista belongs to the oldest lineage of toothed whales that are still alive today.
“One of the most useful ways we can study Platanista is… by looking at fossils that are related to it to try to get a better sense of where it’s coming from,” said Boersma.
“Exactly how that once diverse and globally widespread group dwindled down to a single species in Southeast Asia is still somewhat a mystery, but every little piece that we can slot into the story helps.”
The study was published in the open access journal PeerJ.