Friday, July 30, 2004

Deep sea adaptations - whale bone-eating worms!


'Announcing the discovery of two new species of worms, Osedax rubiplumus and Osedax frankpressi that feed on the bones of dead whales. No eyes, legs, mouths, or stomachs, but colorful feathery plumes and green "roots."

The roots infiltrate the bones of dead whales, digesting the fats and oils inside with the help of symbiotic bacteria, the first time that a lipid-degrading bacteria has been observed in a symbiotic relationship.

The plumes extend into the water and act as gills. Connected to a muscular trunk, the plumes are retractable.

At the other end of the trunk embedded inside the whale bone, the body widens to form a large egg sac. The greenish roots, branching off from the egg sac, are filled with bacteria that break down oil in the whale bones.

Most of the females worms have dozens of microscopic male worms living within their bodies. The male worms looked neotenous, with bodies still containing bits of yolk but also copious quantities of sperm. After a whale skeleton has been consumed, the worms die off, presumably after releasing enough eggs or larvae to colonize another whale carcass.

Key portions of the worms' DNA suggest the worms are closely related to the large tube worms found at deep-sea hydrothermal vents and cold seeps. Both types of worms obtain nutrition with the help of symbiotic bacteria.

The two new worm species' most recent common ancestor lived roughly 42 million years ago, about the same time whales themselves first evolved.'

Read the comnplete story at Monterey Bay Aquarium Reseach Institute.

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