Researchers discover some big, bad ancient worms
`Monster burrow' off Taiwan coast measures two metres in length
OK, they aren't the size of the giant worms that produced the spice on fictional Dune, but they're whoppers, nonetheless.
Simon Fraser researchers have found evidence of underwater ambush worms that are two metres in length and 20 million years old, ancient relatives of today's Bobbitt worms.
Bobbitt worms have no eyes or brains, thus their status as sitand-wait hunters, but they do have slicing jaws to grab their prey and pull it underground. If you were around in 1993, you'll get where the name Bobbitt comes from.
The findings, based on trace fossils of ancient worm burrows off the coast of Taiwan that are no longer under the sea, were published in Scientific Reports on Thursday, with an SFU earth sciences doctoral student, Yu-yen Pan, the lead writer.
“I was fascinated by this monster burrow at first glance,” Pan said. “Compared to other trace fossils, which are usually only a few tens of centimetres long, this one was huge.”
Two metres long, in fact, and a just-as-impressive three centimetres in diameter.
“When I first saw the trace fossil I thought, `This is so cool, it's gigantic!'”
Pan, who was completing her master's degree at the time, and an SFU earth sciences professor, Shahin Dashtgard, were part of an international team that named the burrows Pennichnus formasae. It means beautiful feather footprint, after the feather-like grooves at the top of the burrows. The work was supervised by Ludvig Lowemark at the National Taiwan University in Pan's native country.
They investigated 319 specimens preserved in early Miocene strata from 22 million to 20 million years ago, when the area was deep under the ocean.
Predatory marine worms have existed for at least 400 million years, but their soft tissue bodies decay, leaving little direct evidence of their existence behind. Pennichnus formasae is distinct because it is believed to be the first known trace fossil produced by a subsurface ambush predator, Dashtgard said.
The burrows gave researchers a rare opportunity to learn more about the ancient sand-striker's behaviour through trace fossils: clues left behind by creatures without bones, circumstantial evidence that, just as in a court of law, can be used to prove something if
enough is found to reasonably support the proof.
Things such as fossilized footprints, trails and, yes, burrows.
“The size of the structures was bigger than anything we'd seen in the past,” Dashtgard said.
“You don't normally see worms getting in the order of an inch in diameter. These are some of the first large-scale predator worms that have been found.”
The professor encouraged Pan and the others to reach out to marine biologists and photographers, aquarium keepers, even an uncooperative BBC for a video shoot for the series Blue Planet, to compare the burrows to biological analogs.
“That enabled us to reach the conclusion that this trace fossil was produced by giant, ambush-predatory worms,” Pan said.