Tens of millions of years in the past, large predatory worms so long as an grownup human terrorized the ocean. The fearsome creatures hid below the ocean ground, ready to grab unwitting prey with their slicing jaws and drag them underground to be consumed — like they do immediately, not too long ago found fossils recommend.
The fossils are “very, very distinctive,” stated Shahin Dashtgard, a professor of earth sciences at Simon Fraser College in Burnaby, B.C., who co-authored a brand new examine describing them.
“They’re like nothing we have ever seen earlier than within the rock file.”
In contrast to conventional fossils which might be often shaped from the onerous elements of an animal’s physique, resembling its bones or shell, the worm fossils are “hint fossils” consisting of non-biological traces resembling footprints or, on this case, a burrow. The fossils are described in a study published this week in the journal Scientific Reports.
Dashtgard famous that as a result of worms have delicate our bodies, they’re not often fossilized.
“So, the burrows they make is actually the one file we now have of what the ecosystem would appear like and the way various the ecosystem was.”
Evoke the monsters of science fiction
The researchers suggest that the traditional worm was much like the modern-day Bobbit worm or sand striker, a marine predator that lives in tropical and subtropical seas within the Indo-Pacific Area and grows as much as three metres lengthy. It hides in underground burrows with simply its head uncovered, putting and grabbing prey, resembling fish or shellfish with sharp, scissor-like jaws and dragging them into its burrow.
Bobbit worms are named for the slicing skill of their jaws, which was likened to the slicing that abused wife Lorena Bobbit did to take away her husband’s penis in 1989. They have additionally been in comparison with sand crawling monsters in science fiction worlds resembling Star Wars, Dune and Tremors.
Bobbit worms and their relations are thought to have existed for a really very long time. Fossil jaws of what’s considered the oldest Bobbit worm have been found in a 400 million year old rock formation in Ontario.
However as a result of they’re delicate, worms are not often discovered within the fossil file.
That is why researchers have begun on the lookout for hint fossils of soft-bodied marine animals. Ludvig Löwemark, a professor of geosciences at Nationwide Taiwan College and Masakazu Nara, a professor of organic sciences at Kochi College in Japan, two co-authors of the examine, had been on the lookout for hint fossils of one other historical animal once they got here throughout one thing uncommon in a 20 million-year-old sandstone formation in Taiwan.
Determining what it was grew to become the mission of Yu Yen Pan, a grasp’s scholar working with Löwemark who’s now a PhD scholar at Simon Fraser College.
Key piece of the puzzle
The rock the place the fossils had been initially discovered, Badouzi promontory, was an historical continental shelf about 30 or 40 metres under the floor of the ocean, stated Pan. It was seemingly much like the atmosphere discovered off the coast of Taiwan immediately. Different fossil proof exhibits that it was seemingly a coral reef populated by animals resembling stingrays and different fish, sea urchins and crustaceans resembling shrimp and lobsters.
The primary fossils had been largely fragments left behind by erosion, so the researchers determined to search for related fossils in one other a part of the identical rock layer far away in an space referred to as Yehliu Geopark.
It wasn’t lengthy earlier than Löwemark referred to as Pan over. He had discovered a whole fossil, beginning with a funnel on the high that narrows to a cylindrical tube about three centimetres in diameter, descending straight into the bottom for 70 or 80 centimetres, earlier than bending horizontally into an L-shape, reaching a complete size of about two metres
“We had been tremendous excited,” Pan recalled. “This actually might assist us to attach the puzzle collectively and make the story extra full.”
In complete, the researchers discovered 319 fossil specimens on the two websites. A chemical evaluation of the fossils discovered they had been excessive in iron, which is typical of burrows made by soft-bodied animals. That is as a result of they have an inclination to stabilize their burrows with mucus that pulls microbes that enrich the sediment with iron.
The truth that the tunnel was L-shaped additionally advised that it was made by a soft-bodied animal, as such animals cannot dig too deep earlier than the bottom will get too onerous and compacted for them to proceed, and they should begin digging horizontally.
The burrows had been completely different in dimension and form from burrows constituted of different animals, resembling eels or razor clams.
However when the researchers in contrast the fossil burrows to the burrows of contemporary Bobbit worms, which inhabit trendy ecosystems not a lot completely different from people who the fossil was present in, they appeared very related.
Dashtgard suggests meaning the worms have been dwelling in an analogous atmosphere for fairly a very long time — about 20 million years.
‘Feathery footprint’ from Taiwan
The researchers named their new fossil Pennichnus formosae. The primary a part of the title refers back to the feathery (“penna” in Latin) “footprint” (“ichnus” in Latin) left within the high “funnel” of the burrow by the best way the sediments had been disturbed when the animal pulled its prey inside. “Formosae” after Formosa, a former title for Taiwan, honours the place it was discovered,
Pan stated the fossil is notable as a result of it offers clues about looking behaviour of an historical invertebrate, one thing that’s fairly uncommon.
David Rudkin was one of many researchers who studied the Ontario Bobbit worm jaw fossils however was not concerned within the hint fossil examine. Rudkin, a retired assistant curator on the Royal Ontario Museum and a retired lecturer on the College of Toronto, stated whereas he is not an knowledgeable in hint fossils, he discovered the interpretation within the new examine “fairly convincing.”
“The kicker, after all, can be discovering a direct affiliation within the type of both ‘jaw’ components or soft-body bits throughout the burrows, left after the animal died in place,” he stated in an e-mail.
Sadly, the situations that protect burrows and people who protect our bodies are usually fairly completely different, so that they’re not often discovered collectively, he stated.
“Below the circumstances,” he stated, “I believe the authors have accomplished a pleasant job of constructing the case for these being Bobbit burrows!”
Extra burrows more likely to be discovered
Murray Gingras is professor on the College of Alberta who research traces made by trendy animals and compares them to the fossil file. He wasn’t concerned within the new examine however has gone to Australia to review the burrows of contemporary Bobbit worms as a part of his personal analysis.
One problem with hint fossils, he stated, is that many animals could make very related traces and determining which one any given hint got here from requires some interpretation. However on this case, he thinks the researchers’ interpretation is affordable and effectively argued.
“I believe it is a enjoyable discovery,” he stated.
He stated he is shocked such fossil burrows have not been discovered earlier than given how widespread Bobbit worms are and the way conspicuous their burrows are.
He suspects that many extra will probably be discovered now that different researchers know what to search for, and that may assist uncover the animals’ actions and distribution over the previous 20 million years.