Giant predatory sea worms that lived about 20 million years ago planted their prey by jumping from underground tunnels into the seabed, revealing new fossils from Taiwan.
These monstrous worms may have been the ancestors of modern ruined Bobbit worms (Eunice aphroditois), which also hide in holes under the ocean floor and can reach a length of 3 meters. Based on fossil evidence from Taiwan, the holes in the ancient worms were L-shaped and were about 7 feet (2 meters) long and 0.8 to 1.2 inches (2 to 3 centimeters) in diameter, researchers recently reported. new study.
The soft bodies of such ancient worms are rarely preserved in fossils. But scientists have found fossilized footprints, also known as traces of fossils left by worms; some of these scars were probably made while pulling the prey to their doom. Researchers have collected hundreds of these impressions to reconstruct the worm tunnel, the earliest known trace of fossils of an ambush predator, according to the study.
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Bobbit worms are polychaetes or bristle worms that have existed since the early years Cambrian period (About 543 million to 490 million years ago), and their hunting habits are fast and “spectacular,”
Researchers have examined 319 fossilized traces of tunnels in northeastern Taiwan; from these traces they have reconstructed long, narrow burrows that resemble those made by long-lived modern Bobbit worms. And the preserved details in the rock further suggest how many ancient predatory worms could use these dens, according to the study.
“We hypothesize that about 20 million years ago, on the southeastern border of the Eurasian continent, ancient beaver worms colonized the seabed in anticipation of an ambush for transient food,” the study said. The worms “exploded” from their holes as the prey approached, “grabbing and dragging the prey down into the sediment. “Under the seabed, the desperate prey escapes to escape, which further disrupts the sediment around the hole,” the scientists wrote.
As the ancient worms retreat deeper into their tunnel with the shaking prey, the struggle moves the sediment, forming “separate feather-like structures that are preserved in the fossil record.” Researchers have also found iron-rich pockets in disturbed areas near the tops of tunnels; they probably appeared after the worms reinforced the damaged walls with layers of sticky mucus.
Although no fossilized worm remains were found, scientists have identified a new genus and species, Pennichnus nice; to describe ancient animals based on the distinctive shapes of their holes.
The probable behavior that created the tunnels “records a life-and-death struggle between a predator and prey and indirectly preserves evidence of [a] a more diverse and healthy paleo-ecosystem than can only be interpreted from fossil and trace fossil records, ”the study authors said.
The findings were published online on January 21 in the journal Scientific reports.
Originally published in Live Science.