Researchers have recently added two new species to the five existing species of bone-eating worms, National Geographic reports. The new species are named Osedax antarcticus and O. deceptionensis and are likely just a few of many new species of bone-eating worms yet to be discovered in Antarctica, says marine biologist Thomas Dahlgren, a co-author of the study.
Bone eating worms survive by eating the skeletons of whales on the seafloor of the Antarctic continent and several species have been known to feed on a single whale, leading the scientists to conclude that there are likely many more species of bone-eating worms yet to be found.
“Previously research had suggested that Osedax had diverged from groups that inhabited sulphidic hydrothermal vents and cold hydrocarbon seeps,” said Adrian Glover from London’s Natural History Museum in an interview with the BBC. “But was we added in more taxa and more genetic evidence, it implied that they are more closely related to these mud-dwelling ‘beard’ worms. And that makes sense that the ancestor should be a sediment-dweller given what we think about the distribution of whale bones on the sea floor.”
Until now, similar organisms had been discovered in warmer latitudes, but not in the icy waters of the Antarctic. The Latin name for their genus is Osedex, meaning bone devourer. The worms survive by growing root-like structures on the whale. The female worms lack a digestive track and the male worms attach to the females. Researchers conducted a thorough investigation of what happens on the Antarctic seafloor, leading them to discover the worms. To do so, they sunk a whale carcass into the frigid waters off the West Antarctic Peninsula. At two sites, the scientists sunk parts of the whale as well as wood to see what would grow on it. At a third site they sank white bones only, and did not sink the bones to the depth that they did at the other two sites, Nature.com reports.
The landers were brought to the surface about a year later to see what, if any, impact living on the sea floor had had on the bones. The bones of the whales were carpeted with pink-hued worms that had never been seen before. On the other hand, the wood came back in what the scientists described as “pristine condition.” In warmer waters, wood is usually rapidly infested with “shipworms” after being sunk, but there was no noticeable damage to the wood in the Antarctic waters, suggesting that the shipworms prefer a warmer climate. This revelation suggests that ships of previous Antarctic explorers that sank might still be in good condition. Scientists are fascinated by the abundant presence of the bone-eating worms and the entire lack of the wood-eating species. Andrew Thurber, an oceanographer at Oregon State University, explains that the Antarctic Circumpolar Currant is thought to have prevented the passage of species into the Antarctic waters. The presence of the bone-eating worms suggests that they might have crossed the current during their evolutionary history.