The most lovable marine animal dolphin were swimming the ocean six million years earlier than previously thought, a thrilling research reveals.
Modern dolphins like the bottlenose dolphin have ancient ancestors that went back up to 13 million years.
"This is six million years further back than the first dolphins were thought to be alive," researchers said.
The oldest dolphin species has been named Eodelphis kabatensis.
"Eodelphis kabatensis informs us about the morphology of early dolphins," lead Japanese author Mizuki Murakami was quoted as saying.
The skull of Eodelphis was collected from a small tributary of the Oshirarika River in Hakkaido, Japan.
Researchers narrowed its age to the late Miocene period, 13 to 8.5 million years ago, making it the earliest true dolphin species described.
The new study has been published in the Journal of Vertebrate Paleontology.