Researchers have discovered the oldest fur seal fossil, which could be the missing link to fill the 5-million-year gap in the evolutionary history of sea lions and fur seals.
Paleontologists, Robert Boessenecker, a Ph.D. student at the University of Otago, and Morgan Churchill from the University of Wyoming found the fossil while going through the fossil collection at the John D. Cooper Archaeological and Paleontological Center in California. Boessenecker said that they could instantly tell that the fossil belonged to an ancient fur seal.
The researchers have named the new genus and species of fur seal as Eotaria crypta. The meaning of genus name Eotaria is ‘dawn sea lion’.
Boessenecker said, “This was very exciting as fur seals and sea lions — the family Otariidae — have a limited fossil record that, up until now, extended back to about 10 to 12 million years ago. Yet we know that their fossil record must go back to around 16 to 17 million years ago or so because walruses — the closest modern relative of the otariids — have a record reaching back that far.”
According to the researchers, Eotaria crypta wasn’t recognized from the beginning. When it was discovered in the past, the paleontologists believed that is was a walrus fossil. The remains actually are a piece of a jaw and some teeth and it has been found in a rock formation in Southern California. The date that has been calculated gives a partial temporal expression to the fossil. It is believed to be 15-17 million years old. Also, the rock is not a recent discovery, but one of the 1980s, even if the information hasn’t been put together until now.
The researchers have now spotted the teeth of this newly identified fur seal fossil, which makes it the key transitional piece. According to the researchers, the fossil belongs to the middle ground between the teeth of today’s sea lions and the complex “bear-like” teeth that were seen in the earliest pinnipeds, scientific name of the group of seals.
The findings were published in the journal Biology Letters.