Sat, Jan 23, 2021 page2

• Fossil divers discover lair of prehistoric giant worm

  RE-EMERGED: A National Taiwan University professor and others found 319 up to 20 million-year-old burrows, possibly of a creature related to today’s Bobbitt worms

  • The Guardian
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  The undersea lair of a giant worm that ambushed passing marine creatures 20 million years ago has been uncovered by fossil hunters.

  Researchers believe the 2m-long burrow found in ancient marine sediment housed an prehistoric predator that burst out of the seabed and dragged unsuspecting animals down into its lair.

  The creature may have been similar to the ferocious Bobbitt worms of today, which lie in wait in sandy seafloor burrows with antennas protruding to sense passersby.

  Although soft-bodied, the worms possess sharp and powerful jaws that can slice a fish in two.

  “After 20 million years, it’s not possible to say whether this was made by an ancestor of the Bobbitt worm or another predatory worm that worked in more or less the same way,” said Ludvig Lowemark, a professor at National Taiwan University’s geosciences department. “There’s huge variation in Bobbitt worm behavior, but this seems very similar to the shallow water worms that reach out, grab fish and pull them down.”

  Bobbit worms, or Eunice aphroditois, take their names from the John Wayne and Lorena Bobbitt case, in which the latter — after years of physical and sexual abuse — cut off the former’s penis with a kitchen knife.

  Lowemark and his colleagues discovered the fossilized lair and others like it while studying 20 million-year-old sedimentary rock on the northeastern coast.

  The burrows are strengthened with mucus and are more resilient to weathering, meaning they sometimes protrude from the fine sandstone rock faces.

  The research team was initially mystified by the fossils, but gradually converged on a likely suspect.

  At the top of the 3cm-wide burrows they noticed a distinctive pattern that looked like several inverted funnels stacked on top of each other. This gave the opening of the lair a feathered appearance in cross-section.

  Having ruled out other burrowing creatures, such as shrimp, and marks left by stingrays that blast the seabed with water jets to expose cowering prey, the scientists concluded that the feathered entrance to the lair was caused by a hunting strategy similar to the Bobbitt worm’s.

  When the worms pull their prey down into their lair, the top of the burrow collapses and the worms have to rebuild it before ambushing their next meal.

  “This results in the stack of cone-in-cone structures that form the ‘feathers’ around the uppermost part of the tube,” Lowemark said.

  In an article in Scientific Report, the researchers describe 319 such shallow water burrows preserved in 20 million-year-old sandstone in New Taipei City’s Yehliu Geopark and on the nearby Badouzi promontory, suggesting that the local seafloor was colonized with the beasts.

  The trace fossil burrows, named Pennichnus formosae, are vertical for the top meter, then run horizontal for another meter or so, perhaps because deeper sediment is harder to burrow into, and the water there is less oxygenated.

  Bobbitt worms breathe by absorbing oxygen through their skin.

  The researchers hoped the burrows might contain fossilized remains of prey or the worms themselves, but have found none so far.

  One possible reason is that burrowing worms often inject their feces into the water and let it drift away, spreading bone fragments from past meals far and wide, Lowemark said.

  Lowemark harbors a dream to one day study Bobbitt worms in the wild.

  “They are impressive animals,” he said. “You don’t necessarily want to snorkel too close if you find one.”
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