A species of subaqueous worm unseen for decades has reappeared. LiveScience reports that what was previously the one and only specimen of a type of acorn worm, the Glandiceps abyssicola, was lost to a bombing in World War II. That was the last it was seen of until 2009, when a small, yellow fragment was found in a sample of sediment gathered from the Atlantic Ocean in equatorial South America. Researchers led from UC San Diego have since performed a genetic study on the sample, and in a paper published last month revealed that it came the from the body of a Glandiceps abyssicola worm — making it seemingly the second one ever found and identified.

The Glandiceps abyssicola likely hasn't been seen for decades because of its fragile makeup, reports LiveScience. Traditional dredging techniques for acquiring specimen from the ocean are reportedly very rough, which makes it hard for the body of a Glandiceps abyssicola to stay together. The worm is located deep in the ocean as well, where it crawls around and feeds on detritus. That may make it just as hard to come by a third specimen, as one researcher told LiveScience the best method for collection would be a small underwater vehicle capable of delicately picking them up.