zombie worms
April 15, 2015

Zombie worms may have significantly altered fossil record

Chuck Bednar for redOrbit.com - @BednarChuck

Deep-sea scavengers known as zombie worms have been around for approximately 100 million years, and may have had a tremendous impact on what types of fossils remain today, according to new research published Wednesday in the journal Biology Letters.

In the study, researchers from Plymouth University explain that they discovered bore-holes that were indicative of these bone-eating annelids in a fossilized plesiosaur flipper and in the rib and shell of an ancient sea turtle, and suggesting that they may have consumed much more.

The deep-sea scavengers predate whales

Zombie worms are members of the genus Osedax and were first discovered by researchers from the Monterey Bay Aquarium Research Institute using an autonomous submarine off the coast of California in 2002. They have been found in depths of up to 2.5 miles (4 kilometers).

According to BBC News, the worms are about the same length as a human finger, and they do not have a mouth or a digestive system. Instead, they use root-like tendrils to burrow into bone, then feast on fatty molecules to survive. Previous research suggested that the creatures evolved along with whales, but the new research suggests that they have been around much longer.

In fact, Dr Nicholas Higgs of the Plymouth University's Marine Institute and his colleague Dr. Silvia Danise from the School of Geography, Earth and Environmental Sciences concluded that zombie worms must have been around 100 million years ago, before plesiosaurs died out.

“Our discovery shows that these bone-eating worms did not co-evolve with whales, but that they also devoured the skeletons of large marine reptiles that dominated oceans in the age of the dinosaurs,” Dr. Higgs explained to the BBC. “Osedax, therefore, prevented many skeletons from becoming fossilised, which might hamper our knowledge of these extinct leviathans.”

Did zombie worms prevent bones from becoming fossils?

Using CT scans to compare the shape of different holes created by the worms, the study authors found evidence that Osedax species were responsible for creative cavities in a plesiosaur corpse. They created 3D scans of two bore holes left in the creature’s flipper bone, as well as four from the sea turtle skeleton, and found that they closely match those found in modern whales.

The findings imply that the zombie worms might have gobbled away at the bones of plesiosaurs and that they may have even consumed entire skeletons before they became fossilized. Not only do the creatures bore holes in bones, but they may have created a gaping one in the fossil record itself, Dr. Higgs and Dr. Danise explained to the British media outlet on Tuesday.

“The increasing evidence for Osedax throughout the oceans past and present, combined with their propensity to rapidly consume a wide range of vertebrate skeletons, suggests that Osedax may have had a significant negative effect on the preservation of marine vertebrate skeletons in the fossil record,” said Dr Danise. “By destroying vertebrate skeletons before they could be buried, Osedax may be responsible for the loss of data on marine vertebrate anatomy and carcass-fall communities on a global scale.”

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