Henry David Thoreau: I wished to live deliberately

An international team of scientists, led by the researchers Yu-Yen Pan, Ludvig Löwemark, and Masakazu Nara, have found trace fossils from gigantic ambush-predatory marine worms. The authors of the report believe that these worms were up to 3 meter-long. They were hunting by bursting out at their preys and dragging them into their underground lairs below the seafloor.

Pennichnus formosae

The scientists found 319 large, L-shaped burrows on the northeast coast of Taiwan. These burrows are trace fossils, which means that they are not parts of an organism's body, but rather something like footprints or the marks likely made when the ancient worms while dragging prey to their death. The fossils are up to roughly 2 meters long and 2 to 3 centimeters wide. Their shape suggests that these were the lairs of Pennichnus formosae – the Latin name that the researchers gave to the ancient monster worms. They may have been the ancestors of modern Bobbit worms (Eunice aphroditois), which are also burying themselves into the sand to wait for their prey.

Trace fossils

Marine worms have existed since the early Palaeozoic, but because they are invertebrates and have no bones, there are rarely preserved. The discovery of these trace fossils could lead to new methods and further explorations of similar ancient creatures. This study provides scientists with priceless information about the nature and the behavior of these sea animals, which lived beneath the seafloor. These newfound fossils are among the first to hint that invertebrates fed on vertebrates, Löwemark noted. "Usually vertebrates such as fish feed on invertebrates such as worms," he said. "Here, the table has been turned!"

The findings were published online Jan. 21 in the journal Scientific Reports.