Fossil hunters discovered the lair of a giant undersea worm that ambushed transient marine creatures 20 million years ago. Taiwan.

Researchers believe that the two-meter-long burrow found in ancient marine sediments once housed a prehistoric predator that exploded from the sea floor and pulled unsuspecting animals to its lair.

This creature may be similar to today’s ferocious „Bobbit worms“ that wait in sandy sea floor burrows with prominent antennae to sense bystanders. Although soft-bodied worms have a sharp, powerful jaw that can split the fish in two.

„After 20 million years, it is not possible to determine whether this was done by the ancestors of the Bobbit or another predatory worm that worked roughly the same way,“ said Professor Ludvig Löwemark, a sedimentologist at National Taiwan University. „There is a lot of variation in the behavior of the Bobbit, but this looks very similar to the shallow water worms stretching it and catching the fish and pulling it down.“

Bobbit worms, or Eunice Aphroditus, Take their names from The Case of John and Lorena Bobbitt, Where the latter – after years of physical and sexual abuse – cuts off the former’s penis with a kitchen knife.

Löwemark and colleagues discovered the fossil cache and the like while studying a 20-meter-old sedimentary rock on Taiwan’s northeast coast. The burrows are strengthened with mucus and are more weather-resistant, which means they sometimes protrude from delicate sandy rock faces.

Scientists were at first baffled by the archaeological excavations, but gradually they met up with a potential suspect. At the top of the 3 cm wide burrows, they noticed a distinct pattern that resembled several upturned paths stacked on top of each other. This gave the den hatch a feathered appearance in cross-section.

After excluding other burrowing creatures such as shrimp, and stingrays left marks that burst into the sea floor with water jets to expose lonely prey, the researchers concluded that the entrance of the feathers into the cache resulted from a hunting strategy similar to that of a bobbitt worm.

When the worms drag their prey into their lair, the top of the burrow collapses and the worms have to rebuild it before they ambush their next meal. “This results in a pile of conical structures that form ‚feathers‘ around the top of the tube,” said Löwemark.

Writing for Scientific ReportsResearchers described 319 shallow burrows in shallow water preserved in the 20-meter-old sandstone of the Yehliu Geopark and on the nearby Badouzi outcrop, indicating that the local sea floor was colonized by monsters. Traces of fossil burrows, named Beautiful Piniknos. Vertically up to the upper meter, then run horizontally for another meter or so, perhaps because deep sediments are difficult to dig, and the water there is less oxygenated. Bobbit worms breathe by absorbing oxygen through their skin.

Researchers hope the burrows will contain fossilized remains of prey or the worms themselves, but they haven’t found any yet. One reason, Löwemark said, is that burrowing worms often inject their feces into the water and let them wash away, spreading bone fragments from previous meals on a massive scale.

Löwemark dreams of studying Bobbit worms in the wild one day. He said, „They are wonderful animals.“ „You don’t necessarily want to dive in too soon if you find one.“