London, April 21 (Inditop.com) Scientists have stumbled on the first fossil boreholes of the worm Osedax that consumes whale bones on the ocean floor.
A team led by Steffen Kiel of Christian-Albrechts University in Kiel in Germany has concluded that “boneworms” are at least 30 million-years-old.
Six years ago Osedax was first described based on specimens living on a whale carcass in 2,891 metre depth off California. Since then paleontologists have been searching for fossil evidence to pin down its geologic age.
Researchers at the Institute of Geosciences at the Christian-Albrechts-University found 30 million-year-old whale bones with holes and excavations matching those of living Osedax in size and shape.
The evidence of the boreholes and cavities made by the living worms was provided by Greg Rouse (Scripps Institution of Oceanography), one of the original discoverers of Osedax.
To produce accurate images of the fossil boreholes, the bones were CT-scanned by the scientists.
The fossil bones belong to ancestors of our modern baleen whales and their age was determined using so-called co-occurring index fossils.
“The age of our fossils coincides with the time when whales began to inhabit the open ocean,” explains Steffen Kiel, who has been working on the evolution and fossil history of deep-sea ecosystems for many years.
Only from the open ocean dead whales could sink to the deep-sea floor where they served as food for the boneworms.
“Food is extremely rare on the vast deep-sea floor and the concurrent appearance of these whales and Osedax shows that even hard whale bones were quickly utilised as food source,” Steffen Kiel explained.
The ancient bones were found by the American fossil collector Jim Goedert. He has been collecting fossil along the American Pacific coast for more than 30 years and is well known in the scientific community.
Kiel says: “I got to know Jim when I was a PhD student, when he visited Hamburg University. We kept in touch ever since.”
By now, Kiel has done several field trips with Goedert to the US Pacific coast, a geologically active area where fossil-rich sediments are continuously uplifted by plate tectonic processes, says a Christian-Albrechts release.
This result was published in the current issue of the Proceedings of the National Academy of Sciences.
