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New worm species found in unusual habitat: Dead whale carcasses

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Living whales may seem scarce in the world's vast oceans—and their carcasses even more rare. But to animals and bacteria that feed on these graveyards, they are a rich source of life. And to one doctoral researcher in Sweden, they proved to be a source of several new species. 

In her dissertation for the University of Gothenburg, Helena Wiklund describes nine new species of polychaete worms found living in whale carcasses and other nutrient-rich areas off the coast of Sweden, Norway and California.

A whale carcass can bring as much nutrition to the seafloor as would otherwise take some 2,000 years to filter down. Wiklund and her coauthors note that although the worms seem to be especially adapted to live in environments such as whale falls, where they feed off the bacteria that cover the bones, they seem to also be thriving in bacteria-rich areas of waste resulting from human activity, such as below fish farms and even pulp mills.

One of the new species—the Vigtorniella ardabilia, a chrysopetalid annelid—was described in a paper published earlier this week in the Zoological Journal of the Linnean Society, and three others—of the Ophryotrocha genus—were described earlier this month in Zootaxa.

To find the worms, Wiklund and her team used a remotely operated vehicle (ROV) to collect whalebones from the sea for sampling. By using genetic analysis back at the lab, the researchers were able to establish more new species than met the eye—and even the microscope. Several cryptic—or sibling—species that looked like one another, in fact, had a much different genetic makeup. She was also able to compare genetic differences and find that two cryptic species—of the Vigtorniella genus—appear to have diverged about 29 million years ago, more than 20 million years after early whales began to appear in the oceans.

"Without the use of DNA data," Wiklund writes in her dissertation, "cryptic species pairs would probably be reported as one single cosmopolitan species, and we would not only underestimate the true biodiversity, but also miss the opportunity to gain an important understanding of evolution and specification in these organisms."

Image [above] of the Ophryotrocha craigsmithi worm curtosey of Helena Wiklund; image [right] of whale skeleton courtesy of Craig R. Smith