After a few decades of believing an ancient fossil belonged to a sea walrus, a postdoctoral student in New Zealand discovered the fossils actually belonged to the oldest fur seal. This could be the missing link to fill the 5-million-year gap in evolutionary history of fur seals and sea lions.
Robert Boessenecker, a Ph.D. student at the University of Otago, and Morgan Churchill from the University of Wyoming discovered the fossil while going through the fossil collection at the John D. Cooper Archaeological and Paleontological Center in California. Boessenecker said they were instantly able to determine the fossil belonged to a fur seal, the Tech Times reported.
“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,” said Boessenecker.
The fossil was first discovered a few decades ago but was misidentified as the remains of a walrus species. Boesseneckerr said that the fossilized part of the jaw, which has some well-conserved teeth, was actually recovered at a Southern California rock formation that extends back to about 15 million to 17 million years ago.
However, this discovery suggests that the fossil belongs to a tiny fur seal, which may have been similar in size to a youth New Zealand or southern fur seal and slightly bigger than an otter.
The researchers said they have named the new species of fur seal Eotaria crypta. The researchers also say that it is still a mystery that only one fossil of the early seal exists on record because fossil excavations at similar rock formations in California have been an extensive process.
The study was published in the journal Biology Letters.