The Predatory sand Bobbit Worm can grow up to 3 meters in length.
Hidden around coral reefs under the seafloor, giant Bobbit Worm(s) wait until an unsuspecting fish swims close enough for them to nab and pull back into their sandy burrows with their jagged, agile jaws. The worms have earned the reputation of sand strikers for these quick, deadly attacks.
In the now, recently found fossilized burrows detailed in the journal Scientific Studies suggest that in what is now northern Taiwan, variants of these voracious sea worms were possibly snacking on unsuspected fish around 20 million years ago.
In 2013, when he found a collection of unusual burrows, Kochi University biologist Masakazu Nara searched 20 million-year-old rocks in Taiwan for fossil impressions of stingray feeding behavior. It seemed at first that these L-shaped burrows were made of ancient shrimp, says Ludvig Löwemark, a paleontologist at the National Taiwan University and co-author of the report.
“The fact that nobody had seen something similar convinced us that this is a new trace fossil species,” Löwemark says. “It’s not one feature that convinced us this burrow was made by a worm,” Löwemark says, “but the combination of features.” The tops of the burrows seemed to have collapsed and left feather-like impressions in the rock, suggesting they were used over and over by an animal moving in and out. “The funnels indicate a violent event,” Löwemark adds.